Another productive weekend of tuning the engine and the transmission. The transmission tune has been a little challenging because of the torque converter and camshaft (for different reasons). Mike says because it's a little 'loose', that we need higher RPM to keep some of the chugging down (it would shift into third, then we'd feel this odd shake that Mike thought was the TCC locking up in error, it wasn't). Changing the shift points has alleviated most of those issues. Downside is 4th gear won't come on till about 65 (for now), and the TCC won't kick in till about 70. If we still get shuddering with the TCC, he'll just leave it turned off for now, until we can send in the torque converter to get it adjusted. This also means my MPG is going to suuuuuuuuck.
Engine tuning for driveability is pretty much done. We gradually raised the RPM cutoff, and upped the boost a tiny bit (capped at 7psi right now). Startups are still an issue, but we noticed something odd when we were tuning for that. When starting it, I had to give it a little gas (RPM up to around 1800) for it to stay running. The FAST was reading 0-1% for the TPS! That's not right...
Here's where it gets stranger, after about 30 seconds I slowly let up off the pedal... as I do, the TPS reading creeps up! No pedal, FAST things the TPS is at 2-3%. When driving it, TPS seems to read correctly!! So this is what I think right now.
I know we replaced the IAC. I thought we had replaced the TPS as well once already because the original one wasn't sending a signal to FAST at all. So next weekend we're going to ohm out the TPS wires. If they're all good, I'll buy a FAST TPS to see if that solves that oddity.
We also did some testing and tuning with the brake proportioning valve. After that was done, Mike did a brake launches in a deserted parking lot. He was surprised when the rear tires broke loose and did a burnout, given we have those z06 wheels and Nitto 555 tires on there, and all the weight sitting over the axles. So he's curious to see how tough it'll be to get it to hook and launch well at the track as we turn the boost up. I might have to get a set of slicks sooner than expected. He tried explaining to me that most of your 1/4 mile or 1/8 mile time is made in the first 60'. If you don't do well in that space, it's hard to make up for it.
I also have a few videos I need to get off my phone so I can post them. This isn't the montage that Mike was working on, that isn't done yet. Just stuff I recorded while in the passenger seat.
The new FAST TPS went on, we did the TPS learn sequence, and immediately saw some improvements with cold and warm starts. Hot starts are still a little twitchy, but it's much closer now.
We noticed a behavior Mike called "trailer hitching" at certain RPMs when keeping an even speed. We then did more transmission tuning, and it's running much smoother now. We reconnected the wire for the torque converter lockup, and didn't feel the shuddering we had before, but we didn't get on the highway much today. We also turned up the boost a little more, we're around 8psi now.
Mike is fairly happy with the brakes. He took the car out to an empty spot and tested heavy braking to see how the car would behave - he was worried about the rear end swinging around. He did have to do a little corrective steering, and said he wanted to look into options to increase the braking for the rear. So I'm going to look into brake caliper upgrades the Corvette guys run. Given that I have the S10 brake booster upgrade already, I hope those two things will work out well. And we have the adjustable proportioning valve if the new rear calipers are too much.
We have work to do up front to push more air through the radiator. I have a tendency to think farther ahead and get caught up in my own concerns, so I had bounced my ideas off FieroGuru who pointed out some ideas. When I brought them up with Mike, turns out he hadn't overlooked it, just had it a little further down his list since the engine was staying at stable temps right now. I was thinking ahead to what would happen once we have the air-to-water running and A/C. For under the car Mike wants to setup a hinged plate with rubber sides, so if I bottom out on anything, it won't be as likely to get ripped off the car or permanently smashed upwards. The rubber sides will let it 'flap' on the hinge and settle back into it's proper spot.
We also noticed the intake has some resonance, very similar to what my last intake was doing (the whoooshing sound goes away when Mike put his hand on it with a little pressure, same behavior that FieroGuru chased down on my SBC and solved with a clever internal mechanism). So I might see about attaching some kind of bushing to the underside of the decklid so it puts a little pressure on it.
I remember reading about them before and being a little surprised at the price difference. I am about 80% sure that's what I bought. At least once. I say that because I've found like, 4 orifice tubes as I've cleaned up and organized things in my garage. I need to check the part numbers.
This weekend we didn't get much done on my car thanks to the weather, Mike having an A/C issue for his house, and he was installing a motor into one of his other Grand National projects that needs to be done and ready to go within the next few weeks.
He did finish what he calls the "hater pipe". The single outlet tube at the replaces the mufflers at the v-band. It's to remove exhaust restrictions for the track. You can definitely hear more of the cam-chop when that is on.
I'm glad I have a few of the headlight control modules. I think mine died. Or the janky headlight switch in the beat-up instrument cluster we stuck in there for now died. CowsPatoot is going to be out there way in June before Carlisle, I asked if he would help with some of the stock Fiero stuff, since he knows a bunch of this stuff by heart. So I'll be asking him to help with stock internal wiring (like the headlight situation, the "power trunk release / emergency brake" safety feature (the donor was a manual), and working with Mike to get a few more gauges working (like the speedometer) before Carlisle if possible.
Cold start up tune is getting closer! Sometimes it won't quite stay running on the first attempt, but will on the second. Some more cold tuning is still required, if you put it into gear right after it starts up, the load is enough to make the engine stumble and die. Which is frustrating. Still tuning shift points. We thought we had it all ironed out, then the TCC started doing silly stuff again. So we need to see what we missed.
Good news on the headlights, the module isn't dead. When that motor is winding up, it moves fast enough that it "tightens" itself at the top. This past weekend we were doing some testing with it, and when the light didn't go down, I went to turn the adjustment knob, it was pretty stiff. Once it was loosened, it ran down on it's own. If anyone has thoughts on that, please let me know.
Also still dealing with the start-up-single-swish-phantom-wipe. Chug was out visiting and figured it was the turn signal assembly, but I told him we replaced it and using the turn signals never triggers the phantom wipe, only once during start up.
We got the horn working - sort of. The new relay was put in, fuse under the dash replaced, put the spring and pin under the horn button (I'm apparently missing some plastic piece? If anyone has an extra one to sell or a part number, please let me know. We got it to work, but it's a band-aid). When we hit the horn, the relay buzzes, then one of the horns buzz, there's a delay of up to a few seconds, then the horns sound off. Voltage at the horn relay when the key was off was only around 10.5v. Reading at the battery had us at 12.1v. New Relay on the way. Again if anyone has any thoughts, please let me know.
Mike is working on routing the hose for the intercooler and placing the motor. This upcoming weekend we need to make sure the wheel well covers won't interfere with where he wants to put it. We're repurposing an old electric water pump that was on my last Fiero, so I'm sure there are smaller options out there if we need something different. He also bought a different heat exchanger for me in trade for the one I originally purchased a few years ago, we just don't have the 'stacking space' for it. This one is shorter. It might still be a challenge. We're looking at creative options. Hey, if Bugatti can cram like, 16 radiators into the Veyron, we'll figure this out.
I reminded Mike that I wanted to get all the A/C hoses done and connected so we can make sure there are no vacuum leaks before we fill the intercooler system, just so we're not draining it later and potentially having to move the car around to get it to a dry patch of workspace.
Also! I found my directions that came with Danyel's 3rd Brake Light LED. I'll scan them if anyone needs a copy. I didn't see the instructions for installing it on his sale thread. To install it not only requires breaking/disassembly of a stock bulb then soldering wires (both are no issues), the panel mounts in the housing using hot glue... that part I was a little disappointed in. So I might sell it and buy one of the LED options from SuperbrightLEDs.com (where I had gotten the LED bulbs for my last Fiero's brakelights and they were awesome. There is a side-by-side picture someplace. Speaking of which, I need to find those.)
Anyone want to give any feedback on long term use of Danyel's LED main brakelight kit? I have that too, also not installed. I really liked the look of it, but not sure if it also is hotglued into place. Also wanted to see if anyone has had any issues with individual LED burnout or anything. I really don't want to install them with my restored originals or with either of my Keith Goodyear sets and then have it start to have issues after a year or two - requiring unsealing the assembly, and removing the (possible) glue along with the LEDs).
My only major concern with driving it to PA right now is getting the airdam done in time. All materials we should need have been bought. It won't stop me from getting up there, but might require additional stops while I give the electric pump and fan time to cool things down. When the outside temps were cooler, we were pushing around 210-215 degrees after being on the highway for just about an hour. Not great stuff.
OH! Last question. Can anyone educate me on how to adjust the sunroof lever? On my last Fiero, when you pushed it into the 'up' position, it stayed there and required clear intentional effort to bring it back down. This one, we hit a bump and it flops down.
Good news on the headlights, the module isn't dead. When that motor is winding up, it moves fast enough that it "tightens" itself at the top. This past weekend we were doing some testing with it, and when the light didn't go down, I went to turn the adjustment knob, it was pretty stiff. Once it was loosened, it ran down on it's own. If anyone has thoughts on that, please let me know.
The Storm Trooper left headlight does that on the "down" end of travel. It hits the stop hard enough that, if it's been sitting for a while, I need to manually crack the knob loose before it will drive itself the rest of the way up.
I was told there was some sort of internal limit switch on the 2nd gen motors that could be set to tell the relay when they were at the end of their travel. When I installed rodney's motor upgrade/rebuild parts, I don't recall seeing any such mechanisms. Is this possible? I thought that was only with the first gen motor/setup?
This weekend we worked on mounting the heat exchanger (Mike called it an "after cooler"). It required reworking some mounts up front, and moving the transmission cooler, so we need to remake some of the lines going to the transmission cooler. Even though it looks low in this picture, it's not lower than the radiator, and the front cradle is still the lowest point up front. It does mean I need to watch for sharp transitions when going down a hill, though. There's one gas station here I'll need to be careful with! lol
We're running the intercooler hose behind the rocker panels on both sides. Some pictures to help illustrate the rest:
As it comes out of the rocker up front, it's following the heater tube for a little bit before routing a different path.
Is then runs down under the rocker panel. We took off the rivets and it fits in there nicely. There is a metal lip in there that is easy to cover up. We cut a hole in the plastic near the front and it will be closed up with a snug rubber grommet and a little RTV if needed.
It then comes out of the rocker in the back, and will go up over the wheel well cover. Same as in the front, the hole we cut in the rocker will be sealed up with a grommet and if needed, a touch of RTV.
The intercooler cage holds the intercooler about 5 inches off the floor of the trunk. So we put holes in the side of the trunk where the hose will run in and out, and again grommets will be used.
When it comes back out, it'll circle around behind the bumper, it'll follow the "tunnel" on the bumper, where that red line is, then over the wheel well cover again, and through that rocker panel pocket, etc etc.
After we finish getting this setup, we're going to move onto the air dam!
And cold start is getting closer. Not *quite* there, but getting closer. Warm start is kind of pain still. Hot start is great.
[This message has been edited by Trinten (edited 06-02-2024).]
Intercooler is all setup. With the routing of the hose and the various heights of things, bleeding the air out of it all was a little tough. Overall it took us way longer to get that done today than we thought it would. So we have not been able to start on the air dam yet. I also replaced the orifice tube before we put the reservoir back in.
We took it for a drive, and on the highway it gets dangerously warm, and this is just cruising around without A/C. We are also still having an issue with the trapdoor in the fuel tank sticking. At around 3/4 of a tank, the pump started making it's "I'm out of gas" sound. So we pulled off the road before it died (with only a few seconds to spare, thankfully we weren't on the highway).
We managed to coast to an orientation where the nose was higher, to let gas push back against the trapdoor. After a few minutes the car would start, but die within seconds, so it wasn't pushing the door open. I went across the street and bought a 5 gallon gas can, filled it up to about 4.5, and walked back over and started filling it up. This filled the tank up completely (with maybe a few pints of fuel still in the can). The extra weight of the gas coming in (it goes into the center section, behind the trapdoor), knocked it open, as the car started up without any issues right after that and we got back to Mike's.
I don't know if he'll have time to drop the tank and try to figure out a solution for the trapdoor. For the next tank revision I suggested to use a non-moving "sieve" as the trap door. The viscosity of the fuel slapping up against a bunch of tiny holes will likely slow it down enough and keep some fuel at the back until forces change and gas is being driven to the back of the tank again. Mike didn't comment on this idea, so I don't know if it's a good idea or not. I also suggested trimming up my 'lower wedge' (the ~1" that comes off the bottom of the tank on an inward angle, making it more of a trapezoid shape when looking at it from the back), and making that go from the 'wedge' to an upward angle towards the nose to help push gas back. It'd reduce the capacity by maybe a quarter of a gallon. Again no comment from him on the idea. That usually means he's at least considering it.
I did discover I ordered the wrong bushings today to put around the hoses going into/out of the trunk. We worked up a temp solution, but It's not great, so I need to order the right stuff.
Will the car still go to Carlisle? I'm not as optimistic right now. If we finish the air dam, we still have the trapdoor getting stuck. Granted I have a 5 gallon metal "jerry can" that I was going to put in the trunk anyway, but I've got a fear of being on a stretch where there isn't a gas station for longer than I can make it if the tank acts up, even with the emergency fuel.
I am going to price out a car hauler. I can drive it around locally once it's up there, so it'll get to the show under it's own power.
To end on a positive note, Mike got the cold start dialed in. Today each time we needed to start it when it was cold, it fired right up on it's own. Still need to work on the 'warm start', that's still a little twitchy.
[This message has been edited by Trinten (edited 06-08-2024).]
Mike spent a few days after work mocking up and testing out an air dam. The throat started below the bumper 'nostrils' to be able to grab more air, and then went back, boxing everything up. He took it for a drive and we have mixed results.
Cruising on the highway is now stable (though the ambient temps were still only in the low 80s). However when coming off the highway, if needing to come to an immediate stop, the heat soak from not moving caused the temps to climb up to 240. Once he was moving, they'd drop back down.
Currently the main fan and the water pump are set to run at 100% all the time. This is because I've had a tough time getting the controller for the BMW pump to accept the custom program I was trying to put in (BMWs ramp up their pump speed as needed. I wasn't happy with any of the preset options. For example some had the pump only running at 5% until a certain temperature was reached. Well, the heat sensor is in the front, engine is in the back... I wanted the pump to start at 20% flow, then ramp up to 100% by the time the coolant hit 180 degrees). The company's tech support was really responsive in trying to help me figure out why it wasn't setting correctly. Since I want to get a second one, they said they would pre-program the setting for me.
I digress. Mike and I talked about next steps. The headlight flaps are currently still off, so hot air has an easier time escaping. After Carlisle we'll likely cut a window in the hood in the radiator area. I'm also going to talk to him about moving the secondary transmission cooler. There are units out there that come with their own fans, we just need to find a place to package it (and run another key-on circuit). The where is going to be the toughest part. We're out of room in most of the obvious places. The ones that have some room left are in or right next to the engine compartment, which is a boiler room. Maybe under the front bump on the passenger side? Basically opposite of the headlight control module. It'd mean cutting some breathers into the bumper, but eventually I'm getting a bunch of new body work done, so I'm not concerned about that.
Last option is to pull the current radiator and ship it to one of those places that do custom radiators, with explanations of what can and can't be changed (for example, some 'depth' can be added, if they make it a little shorter, but all plumbing points have to stay in their current spot). See if they can come up with something that has a better cooling capacity. I will also ask Mike about cutting a few pass-through holes in the metal shroud holding the fans on the back of the radiator. That way at highway speeds, the air will have more channels to push through.
I did call AFCO and asked them if they had a better fan/shroud solution for that radiator (it all came together) they said they didn't. The guy I talked to asked for some details and I think at first he thought I was kidding when I told him what we had done. I told him I wasn't the only one jamming LS4s and turbochargers into Fieros. It was a fun conversation.
We also haven't had time to figure out how to mount and power my "exhaust fan" for the engine compartment. I have a Spal fan that will fit on the underside of the vent. Mike needs to modify the vent (likely welding on some nuts) so we can mount the fan to it... and of course, get some Key-on power to it. I figure something that's actively pulling air up/out of the engine compartment is going to help.
If anyone has any other cooling ideas, please let me know!
Holy crap it's been practically two months since I last posted. I'm sorry guys. June was getting ready for Carlisle, and since getting back life has just been... a lot.
Carlisle was great, but SO DAMN HOT. We brought cases of water, bags of ice and contributed our cooler to the community club tent for everyone (as did many others. It's a great club). It also meant on voting day not many people wanted to walk the whole line of cars, which was a little sad.
Boomtastic had this amazing cleaning product that he let me use to clean up the Z06 wheels... yes I know, as ugly as the rest of the car is, it was like sprinkles on a turd, which is why it was so damn funny to me. I also had fun with the club members that did come by that hadn't seen the car in past years, and get to ask them "how do you like my strut tower mod?" and they would do a double take and freak out.
I found hot pink duct tape and put a piece on the underside of the deck lid, and wrote on it "If you can't find my strut towers, you must pick me for best engineered!" I didn't win anything this year, I apparently forgot to check the "WIP" box, and another guy with a stretched Fiero with a Lambo-tribute body and longitudinal engine setup won. And I don't fault him for that - that's a lot of damn work!
I did see another car there that was running the 4T80 Transmission though, and not on a Caddy engine!! I tried to find the owner a few times, no luck. I keep forgetting to send the guys name to Jen to see if she or someone in the club can pass my contact info along. I wanted to pick his brain on his TCM setup. From his workbook he had in the engine area, it looks like he tracked his car. Had a great little reference book there, bookmarks, notes, very thorough guy.
Onto work since then:
One of the things we really needed to address was the sticking trap door in the fuel tank. Which understandably bugged Mike, but this was a prototype tank, things are bound to happen. After we drained and dropped the tank, he did the 'rocking test'. On the tank he made for his Grand National, he can rock the car and you can hear the trap door 'slap', even with it in the car. That wasn't happening with my tank, even after taking it out.
So we let it it air out for a few weeks, then flushed it with water to be sure, then after much consternation at the ordeal, he cut open a section of the tank so we could get to the trapdoor. Sure enough, it just didn't want to play nice. We don't know when it decided to stop playing nice. It could have been the heat from the welds sealing up the last of the tank made the piano hing flex just that much, since it was moving freely during initial assembly.
We discussed options, including getting another stainless piano hinge and strategically removing ... teeth? Whatever you want to call them, to reduce binding points. Or to try to find a "loose tolerance" hinge. In my searches, I found this! - https://behrents.com/parts/atlks145.asp
I found some other options too. In addition to some homebrew ideas. Mike decided to get that ATL part a shot.
Additionally, we swapped out the BMW CWA200 pump for the Craig Davies 150 pump. Originally we were going to go with the CWA400 pump. Way more flow, more pressure, and only a 1.5% larger housing, same housing style. I even confirmed that the TinyCWA controller I had would work with (appropriate versions) of that pump with just a wiring change.
Why didn't we do that? Two reasons: 1) The CWA solution was to give us the advantage of accessible parts. The CWA200 can be found at pretty much any Napa or Autozone. The CWA400.... nope. Special order. 2) If the Davies 150 if keeping FieroGuru's LS4 nice and cool... we're willing to take a good idea and run with it (and as always, give credit where it's due!)
This did require reworking some of the plumbing Mike had fabricated, which was a lot of measure, cut, tack weld, test-fit, finish welding, but it's done.
Hopefully in the next trip or two, Mike will have the gas tank ready to go back in. Then it's back to tuning the transmission. Cold start tune is really good now, but the freaking hot start tune is now worse. Mike dislikes having to use long duration of higher throttle in startup, though that's the direction we might have to go.
Oh! I discovered the honeycomb under my front bumper cover is falling apart. So I need to find another one of those. If anyone knows where I can get them, or has one they'd like to sell, please let me know.
[This message has been edited by Trinten (edited 08-12-2024).]
We put the fuel tank back in, filled it up with 10 gallons of 93, went to Key-on for the pump to prime, I turned the key and the cold-start tune did it's thing, fired right up. We let it idle for a bit so we could burp the air out of the coolant system.
Once it seemed all was flowing, we jumped in and took it for a spin around the immediate area. No more fuel starvation! So the old fuel trap door was the issue, and the new one seems to be working just fine.
We're still dealing with the transmission tune, getting the torque converter to lock up when we want it to. It still likes to engage in the 50mph range, even though we set it to come on at like, 74 (as an extreme test, we wanted it to be 62), and doesn't like to turn off until we drop into the 30s. So another day of doing a lot of manual shifting into 3rd and back to drive.
With the new water pump and keeping our crude air dam from before Carlisle in place (late June... damn time flies), the temp crept up and stayed right around 210. That still made me a little twitchy, but I did hunt down information on what the GXP operating temps were, and up to 220 was considered normal operating range apparently. That seems nuts to me, but I'm used to things not going over 205-210 with A/C on.
We wanted to test the effectiveness of our crude airdam, so we popped it off and started driving the same circuit. Sure enough, the temp started climbing, it hovered around 223. Waaay too high for doing 45-55 zones. So we rolled back to the house to end the day. This also means that when we get the A/C hoses installed, there's going to be more strain on the cooling system up front (heat generated by the A/C condenser in front of the radiator).
This does mean that the water manifold on the block is likely not an issue... but I do need to be ready to call up Champion and be like "Let's have a conversation about that custom radiator you were telling me about."
Make has another time crunch Grand National engine he needs to finish (I think he said it has to be built and back in the car by the start of October for an event the client is going to), so I suspect the next few weeks will be all GN, all the time. And if I'm there, it'll be to stay out of the way and be a go-fer. It works out though, he gave me some input on new/different materials to order for the next revision of the airdam, so that'll be on my to-do list.
Next time I'm there, I can at least grab a copy of my current transmission tune, and try to get it over to the reseller who sold us the TCM we're running now, and ask him to put eyes on it. And eventually I need to pick up my original transmission from the shop - he hasn't called me yet, and I did tell him it was low priority. Hopefully... low priority doesn't accidentally translate to "what is this doing here? Where's the paperwork? Scrap it." Only half joking here.
While going for a test drive (transmission stuff, I'll come back to that). We hear a *ping-clatter-clatter* from the passenger side... and the side mirror falls off. Thankfully the wiring (!) connector didn't break and it wasn't lost to road destruction.
Apparently, both studs in the side mirror have worked themself out. Looking in the mirror base, it seems like most of the threads are gone / barely there. Here's some pics, though it's tough to see. To that end, I was going to tap the hole and put in the next size up stud that I can get. Can anyone tell me what the OEM stud size here was? We had hoped that we could find the stud and nut in the bottom of the door, but no such luck. There is a gap that it must have rattled out through. I was hoping to work backwards and look up the nut size (they have them on TFS, but no measurement details), though that wouldn't tell me how long the stud needed to be.
So if anyone can let me know the answer to that, I would appreciate it. It would save me from having to take the driver side mirror off to take those measurements.
Today we noticed that the transmission is short shifting from 3rd into 4th. Like, so quickly that we hadn't caught it till Mike was watching the laptop readout specifically to watch for shift points. This doesn't explain why the torque converter was locking up at a lower speed than originally set.
So Mike adjusts the tune, wanting to troubleshoot just the shifting issue. He turns off the lockup completely for now, and we do some driving. Sure enough, now that we're not trying to pay attention to the lockup, we can notice the quick up-shift from 3-4. Back to the house (the TCU can't be tuned on the fly, unfortunately). This time he turns off 4th completely (by telling the computer not to shift into 4th until 200 mph).
We get on the road... transmission is wanting to start off in 2nd now. Shifts from 2nd to 3rd.... then start to make an ugly noise. I knock the lever into Neutral and punch the brakes (no one behind me, don't worry). We use the selector to manually set it to 2nd and crawl back to the house to call it a day. Mike said he was going to go through the tune with a fine-tooth comb - no, I didn't remember to bring a thumb drive to try to get the vendor to look at it again.
I asked him if we could have a wiring issue, he said that if it was a wiring issue with the solenoids, we would see problems with more than just one gear, but he would look at the solenoid order just to be sure.
The next startling thing to happen... When we got back to his place, I open the decklid and grab the metal rod we're using as a prop-bar for the decklid. This thing is very warm. Not too hot to hold, but way above ambient temp. The intercooler pump isn't hooked up right now (no space in the fuse box in the back, next thing we need to address). So I touch the intercooler, it is HOT. Mike is surprised, comes over and manually jumps the intercooler pump so water runs through to cool it off.
Sitting on top of the intercooler and laying against the bulkhead into the engine compartment was a trickle charger and a DEI package of insulator. I pick them up... and I'll let the pics speak for the rest.
Isn't that nuts? Mike was shocked it was getting that hot, given the gap from the turbo to wall, turbo blanket, coating on the exhaust, factory trunk heatshield (with the stick on insulator added), etc., so I'll need to put a layer of that temp insulator on the engine side of the trunk bulkhead. Then get some things to monitor the temp in the trunk to find other hot spots. Some 'touch' sensors that I can fix into place, and a general in-the-oven temp gauge to drop in that area and see how hot it gets. At what temp does the trunk carpet become flammable? lol
On the cooling side of things, the transmission temp was staying in a good spot, it never went over 192. I do have the aux. transmission cooler sitting up front, but given that the engine (when running ) was getting up to around 230, I think the radiator is doing it's job. Or else the transmission fluid would be hotter, too, extra cooler or not. Interestingly, when we shut the car off, the temp reading for the engine coolant would drop ~22 degrees instantly. Mike caught and said "That doesn't make sense... start it back up." so I did and the temp jumped back up about that same ~22 degrees. So another mystery to try to figure out. Why does my car like giving us puzzles!!!
Engine tuning, worked on the hot start-up. It seems my engine likes to be really rich for a cold start, and leaner for a hot start. The cold start did not work as intended yesterday, which was a surprise given how good it's been the last few visits.
[This message has been edited by Trinten (edited 09-29-2024).]
Quick preface, I understand this is kind of a long-format, and I give a lot of details. It's not everyone's cup of tea. I do this so I have a record of it for my own memory and documentation. For those that take the time to read through these longer posts, thank you for your interest.
The TL: DR version -- verified TCC was locking up in 3rd. We had to do a neutral-to-drive drop when the engine had some RPMs on it appears to have somehow fixed this issue. Dealing with lingering coolant temp issues and possibly fuel overheating, which makes my fuel pump very unhappy.
Also, I put helicoils in my passenger side mirror, so I can get that back on now.
Long version! Holy crap today was a weird day!
I picked up an "inexpensive" industrial thermometer with a wire probe that logs the temps it records. I positioned the probe about 3" away from the downpipe, near where it exited the turbo. In our 10 minute drive around (max speed limit in the area is 45), the temp reached 375.
I proactively got a variety of higher end thermal insulators.
I got one DEI Titanium Pipe Shield with LavaRock Technology and one DEI Form-A-Shield Heat Barriers.Both are rated for direct contact, which is good because that downpipe is very close to the trunk wall.
Mike had made more changes to the tun for the transmission and changed the settings on what info the laptop displayed. He wanted to see the Input Shaft Speed alongside the 'driveshaft' speed. He said when they lock-in-step it's a clear indicator that the TCC was in lock-up.
We go for a drive... and sure enough. Now this was happening even when we had BOTH wires for the TCC disconnected. So now we knew something was going on inside the transmission. Mike's initial guess is that there was a short and a common event that was energizing the TCC solenoid.
And he thought he found it. 3rd gear only activates one of the solenoids - one that isn't on during 1st and 2nd. So I felt like it was my fault, since I had it apart to do some basic parts replacement, and figured I damaged something.
Annnnnd then we found another issue and (potentially) fixed the transmission issue.
Mike figured we could work on the engine tune, starting to dial things up. So we took it out for a drive (he drove this time, I was keyboard jockey). Coolant temp was staying stable (still too warm for my liking). Mike says we should get some gas and then hit the highway.
On the way to do this, the fuel pump starts it's "death whine" that it was making back when it was starving from the faulty trapdoor. We had run the car lower on gas than it was now with the new fuel door, so this was a little confusing. We couldn't make it to the gas station, we coasted into a CVS across the street and parked. Assumption is that the fuel was getting too hot.
We sit around for about 30 minutes. Key on, the pump is still whining, but not as badly. We decide to try to get to the gas station, across a four-lane street. If we can pump cold gas in there, it would help us figure out if it is a fuel-temp issue.
We get to the edge of the parking lot... engine stumbles and dies. Mike puts the transmission in neutral, when it looked like we had an upcoming break in cross traffic, he starts the engine and revs it up.... and when we have our window, he drops it from nuetral into drive. The car freaking LAUNCHES across the road and we get close to the pump before the engine cuts out again.
We fill up the tank, it starts up, the pump quiets down, but is still a little noisy. We get on the road to head back to Mike's.... and the TCC doesn't do it's weird lock-up in 3rd!
We were so focused on listening to the pump, we didn't realize it at first. We get to Mike's to give it time to cool off, the fuel take was pretty warm.
So we're going to come up with some shielding to guard the fuel pump from the ambient heat it's getting from the exhaust manifold, and I might get a fuel cooler with a fan on it.
Tomorrow Mike is going to drive it around some to see if the torque converter is playing nice now. My amateur opinion if it is working - there was some gunk in the valve body, and when the solenoid for third kicked on, fluid was also getting pushed to lock up the TCC. Mike said it's unlikely, but not impossible. However we have no other explanation of what else could have happened when he did that neutral dump into gear.
Remaining issues now (assuming the transmission is miraculously behaving), figuring out what's going on with my fuel pump, and getting the coolant temp down.
[This message has been edited by Trinten (edited 10-26-2024).]
Damn. Mike texted me to let me know that he did more engine tuning today and turned the boost up to 15 lbs and it's really hauling now, and we'll need to put a two-step on it for the track.
Unfortunately the TCC is locking up again in 3rd gear every time again. When we get the other 4T80e back from the shop, we'll drop this one off and let him know what was happening. Hopefully the shop can find an internal reason for it to be doing this.
If the behavior continues with the checked-over transmission, then I'll look into what is needed to disable the lockup feature -- just unhooking the wires won't do it, as our testing has shown -- and send my current torque converter back to Precision to see if they can convert it to a non-locking style unit.
Are you monitoring EGTs? Possibly timing is too retarded during cruise and superheating the manifolds? It is one of those things you just would not know without monitoring EGTs, running too little timing during low throttle low RPM can easily be missed by feel or just monitoring AFRs.
No, no EGT setup. Mike is logging A/F ratio during our test drives. When I'm out there next, I'll be putting the temp probe near the manifolds to see how hot they get. This is what we'll put over the manifold on the front side, try to cut down on how much heat could be reaching the fuel pump: https://www.summitracing.com/parts/dei-050519
It was originally intended to go around the downpipe, but it's thicker than I anticipated and I don't think it'll fit between the downpipe and trunk wall. If it does fit, I'll just have to get another one.
Mike drove while I stared intently at the numbers on the laptop, watching for when it appeared TCC lockup kicked on. What was interesting is sometimes when it happened, the RPM didn't drop very much. Maybe by 100 or so RPM. Other times, it would drop down into the 1500s, and then we'd get "the shuddering".
It would also shudder in the "lower" range of 4th gear, when the computer commanded the TCC lockup. which we had set to come on at 55 MPH.
I told Mike I was going to bump that up a little, so he told me how to navigate to the table that had the shift points, and (to oversimplify since it's more like a matrix than hard points), I changed all of the 55 MPH 3>4 points to 62, and all of the 53 MPH 4>3 shift points to 60.
Annnd... the symptoms went away. Even when it locked up in 3rd and made the RPMs drop, they were now floating a little over 1600 RPM, so no shuddering. And 4th gear was now smooth the whole time.
Mike was surprised that such a small change would alleviate the symptoms, but we weren't going to complain. We actually had a really enjoyable tuning cruise (he directed me on some changes in the FAST).
Boost was up to 20 PSI, and it's crazy. He dialed it back down to 15 PSI for now. He then spent some time really beating on the transmission, including numerous brake torque launches. With the intercooler running (no ice, just water right now), air charge temp never went beyond 115, and that's when he was really pushing things.
So the next thing he wanted to do was wire up the 2-step switch. Thankfully the Fiero didn't come with a rear defroster, and among my collection of Fiero parts, I had a panel that had the trunk popper and a nicely installed toggle switch where the defrost switch would have been (it was not fitted to replace the defrost switch, it's too small, this was a no-defrost panel that was modified).
Mike wired up a relay and a wire from the brake lights with the toggle (at my insistence), and he started playing with the tune for the 2-step (spark cutoff is how FAST runs it). Drawback was there was some gunshot loud pops in with the "raa-tat-tat-tat" sound. He admitted it wasn't good for the mufflers and we'd need to put on the single-pipe exhaust when using that in the future. At 2800 RPM with the 2-step, the car is still pushing through the brakes. He's going to see if he can come up with anything else to stop that before we turn the 2-step RPM limited down further.
Cold start is still a little challenging. Still needs a little bit of pedal action. Hot start needs a lot of work. "Warm start" is also finicky. The car will start up easily, but if you don't let it idle for a few moments before putting it into gear, the load stalls it out. With that last one, we looked at what the computer was doing, IAC was opened all the way and simply not enough air getting in. He's got some ideas he thinks will fix that.
We also got a the new coolant manifold in. So hopefully next weekend we will be installing that and reworking some things. With the weather getting colder, it's going to be tougher to tell if our solutions now are going to be fixes that will hold up into the summer next year. Fingers crossed.
I changed the oil, and got one of the used oil analysis kits (Napa brand). Mike thought it was a waste to do it for this first change, since there's going to be a lot break-in particulate. It still gives me a baseline.
Vince, good to hear you are making progress on the shuddering.
I forget the size of your camshaft, but the "shuddering" might be from the engine and not the transmission. Low rpms, high vacuum, and a large overlap can pull the exhaust back into the combustion chamber vs. pulling in air from the intake runner and cause bucking. It is more pronounced with manual transmission, but locking up the TCC directly links the engine and transmission like a manual. Adding more timing in that area can help, but are are limits.
It is great you are up to 20 psi! I am slowly working the boost up on mine and only at 7.5 psi. I will likely stop at 8.5 to 9.0 while I run non-intercooled 93 octane. Maybe next year I will get switched to E85 and turn it up more.
Sometime in 2025 we will have to get the cars together!
I don't recall enough of what Mike did when we first started troubleshooting the shuddering. Engine RPM under load was something he explored. When he was finished he was positive the issue was from the TCC lockup and too low of RPM, versus just low RPM and other factors. This is where I wish he had the time to jump on and add technical supplemental commentary to my layman documentation.
Mike is eager to take it to the 1/8 mile track near his house. I made it clear that we weren't doing that until we had the coolant temp under control. The track has test and tunes (almost?) every Thursday evening. I don't know when they'll close the track for the season. Their website is basic, and if you want more info, it directs you to their facebook page, which is setup to where it can't be viewed without being logged into facebook. I'm sorry, Facebook should not be a businesses replacement for a good website.
Their website only shows the rest of their November schedule right now. That also could imply that it closes at the end of November? We'll see.
No, no EGT setup. Mike is logging A/F ratio during our test drives. When I'm out there next, I'll be putting the temp probe near the manifolds to see how hot they get. This is what we'll put over the manifold on the front side, try to cut down on how much heat could be reaching the fuel pump: https://www.summitracing.com/parts/dei-050519
It was originally intended to go around the downpipe, but it's thicker than I anticipated and I don't think it'll fit between the downpipe and trunk wall. If it does fit, I'll just have to get another one.
This is what I bought for my WRX from Harold G. Schaevitz Industries:
Product(s) 1 x PMD1XT Gauge - Blue - 12 VDC SKU: PMD1XT-BL-012-0 $66.50 1 x EGT-MP Probe - 90 degree - 6 ft - Clamp 2" SKU: EGT-MP-072-0000-SS-N+CLMP-2.0 $59.75
Has a very small rectangular digital gauge that gives you a temp readout and you can set an upper warning limit. It is clamp style so you just drill a hole into your hottest exhaust runner and clamp the probe in. You can log it via serial output. It is a high speed probe so it reacts very quickly. Designed for turbocharged engines. For less than $130 it is not a bad idea! The have weld in bung style as well. You can also just log the sensor and go gauge-less all together just for tuning only if you don't feel like monitoring it all the time.
I am just concerned with how high your temps were from just a chill cruise, it screams too little timing to me. If high EGTs go unchecked you can melt exhaust valves and damage turbos and O2 sensors!
Also congrats on getting the trans issues figured out, some in-car video would be cool!
Thank you for the parts/prices! I will check that out.
I will need to take some videos from inside the car, usually I have a laptop to manage. This weekend (assuming I didn't overlook anything when ordering the rest of the new hose components and fittings for the coolant manifold upgrade), I'll try to get some video from inside the car.
This past weekend Mike had me stand on the side of an uninterrupted segment of road to record him doing a brake torque launch, but I'm apparently a terrible camera person, and as the car went by me, I did not appropriately increase my pivoting speed, so it quickly zipped out of frame.
At the very least I'll get some new pics to post of the old manifold, the new one, and the new heat shielding (if we get that far).
Updates! (also, if these pictures upload in super-size, I'll edit and fix it later on)
1. I need to find better options to seal Danyel's LED marker light(s). When securing one to the car, it popped apart. It looks like he might have used superglue for the plastic, and hot glue to hold the LED strip in place. Fiero Store has a sale this week, I might buy some new sets of marker light housings to play with.
2. I found my old lighted Fiero GT HUMOUNT bezel for my single din radio (also still installed). Sadly it looks like Mark / HUMOUNT closed up shop sometime in late 2015 or early 2016? I was going to order one for Mike, he wants to put in a basic single din head unit that has bluetooth so he can stream music from his phone. Oh well, in the meantime, when I get to having some semblance of a dash in there, I'll use this again. I might put in a newer HU, so I can stream from my phone too, or play things off a USB drive or something.
3. I finished putting M6x1.0 helicoils in both of my side mirrors. The driver side was loose, and it was the stud wiggling, so I figured I might as well. I had originally wanted to try to use a bolt. The idea was to slide the bolt out through the door, hold the mirror up near the threads, get the threads started, then 'walk it on'. Unfortunately this had a compound flaw. The first was getting a bolt the right length, as much engagement with the mirror as possible but no slack. Once the ideal bolt length was found, I did not have the space to turn the bolts enough by hand to get them started. Using a socket was out of the question, as the depth of socket and angle meant an auto-fail, and I didn't want to mess around with putting a 'backstop' in the socket.
Unfortunately over the last two trips, I lost all the hardware I had ordered from McMaster (the bolts in question came from Ace). I had ordered studs and a variety of fasteners to see what I liked best, including some heavy duty thumbscrews. While the cost itself is minimal, it's just a mild annoyance.
Mike is taking December off for himself and his own stuff, so I won't be back out there till sometime in January. He did tell me to have the additional AN hose fittings he needs for the cooling system to be sent to him, in case he wants to mess with that for a change of pace, so I did that.
Also, it seems the auto-shifter surround (with gear indicator) I have from one of Mike's Fieros is in pretty rough shape. The main bezel isn't broken, but I do need to replace an ashtray door and spring, however the gear indicator has 'sheared' off the black out paint... and it fell off the bezel. So I need to see if I can fix that or get another good assembly. There were a few on ebay, but one was all painted up and looked a little rough, and one that was in okay shape was going for around 300?? So I'll make due with this for now.
In November, Mike let me know he was taking a little time off to work on his own stuff, and cleaning up/organizing his garage. Then the weather was a little too cold for us to be messing around with draining coolant and such, so we didn't work on it again till this past weekend.
Unfortunately... we discovered the new water manifold we bought would not clear the cam sensor mounting point, and would have been practically on top of the sensor connector.
In the meantime, Mike made the new adapters to step up to the -16 fittings coming off of the coolant tubes, and we made AN hoses. He also bored out a ridge that was inside the -16 fittings (before we put them on the manifold, of course).
Here's some other pics of the new manifold:
Much bigger ports and better transitions than the old manifold I bought:
So Mike took some measurements, and I ordered a set of water manifold stand-offs to move it out a little. We'll see if we run into any new hiccups.
I also finished putting my side mirrors back on. As I mentioned a few posts ago, the original soft metal for the studs stripped out. So I put in M6 helicoils. I bought a variety of lengths of threaded rod to see what was going to work best. 35mm long seemed to be best. I also bought a variety of fasteners, including heavy duty butterfly nuts, and bolts.
The bolts didn't work strictly because of angling and trying to get the threading started. Which is what FieroGuru predicted, but hey, sometimes I gotta learn the hard way. lol
The butterfly nuts worked great. The angle on the 'wings' cleared the angled parts of the metal, and I was able to get them on by resting the butterfly on my index finger, reaching in and gently pressing it on, and a slight motion of my index finger and pushing with my pinky finger get it started. Then it was easy to reach in and push the wings to tighten it down.
I did put a little blue loctite on the studs going into the mirrors, just in case.
We're eager to get it back on the road for longer drives to see how the new manifold holds up. Even with the cooler temps, if we're running it on the highway (versus all of the 55 and under driving we've been doing) that might put enough load on the engine to see how it holds up.
Mike is eager to take it to the track and see how much the transmission will take. I told him I'd rather not do that until we get the other transmission from the shop. Yes, the same shop that's had it almost a year. lol
And there's still dyno tuning to do! This weekend I won't be able to head out to Mike's, I don't know if he'll work on it. Normally I try to be there when he works on it. I don't know if he'll finish it up without me or not. He's always got other things to work on. I'll reach out on Sunday and find out.
Mike did decide to work on the car without me this past weekend (I won't complain). The new water pump standoffs apparently worked great, Mike reported there were no leaks, and he took the car on a 22 mile highway trip to see how it held up. The whole highway trip, the temp didn't go above 190. This is interesting, as we do not have a thermostat in place, and this Davies Craig pump is not setup with any of the fancy controls, so it's running full speed the whole time.
Once he was off the highway and sat at a redlight at the end of the exit, the temp crept up to 209, but lowered back down quickly. Of course the temp was in the 70s, I think. So I'm a little concerned of how it'll be when the summer rolls in, or when I go to use the A/C!
I suspect I'm going to be spending the next few months earmarking some money for a custom Champion radiator.
The other issue Mike worked on was the slow weep we had from the oil feed line, weeping at the AN fitting on the turbo. I did some research and found people that had nylon braided AN hose sometimes had this issue, the temperature apparently melts the nylon braid inside the AN hose end, and that gives space for oil to weep out. Solution appears to be to switch to stainless braided hose, and put a heat sleeve on the line and as much of the fitting as possible to limit how much ambient heat it can absorb. So all of that stuff is ordered.
We still need to build the weatherproof secondary fuse box for the trunk space.
Also, the Fiero Factory seems to have come through for me. They found a shifter surround assembly that was in good shape. I also got a few extra sets of the D-Plates that flank the trunk under the GT clip to keep water out of there.
We put about 70 highway miles on the car this past weekend. It was pretty cold out, around 42 degrees. With that, the coolant temp never got above 152. On the highway after drove a bit, it was sitting in the mid 130s. So if we assume a 1-to-1 increase of temp with outside temp, that means we can expect 90 degree temps to pull the coolant temps up to around 200. And as mentioned before, that's before the extra heat soak of the A/C running.
We have discovered the manifold is (Still) a choke point. At one point, before the coolant system built up some pressure, the upper radiator hose had collapsed, indicating that the draw of the pump was outpacing what the water manifold could let through. Mike is going to replace it with an aluminum tube, butting it right up to the radiator port and hard coolant tube, using a small slice of radiator hose as a coupler, but no gap (or not enough of one) for it to collapse.
We spent the highway miles doing some tuning, trying to get rid of the 'chugging' that we would get at RPMs under 2000 (1800-1950) when cruising at highway speeds. This engine likes to run rich. We would bump up the fuel ratio a tiny bit, and the engine would smooth out more and more.
Mike did a light pull, from 60mph he pushed the throttle to 33% and held it there. That part of the VE table was spot on, every vibration in the engine smoothed out where it felt like it was just gliding. It was wild. It also had an A-F Ratio floating between 11.5 and 12.25 during this pull. It seems when the ratio is higher than 13.25, and RPM is under 2000, we get the shuddering/chugging.
So we have a fair amount of time where we need to chase down all of those uncomfortable chugging points and adjust the ratio. Mike said this is just the price of having a performance/race cam, so he isn't sure if we can get it all out, but to explain how bad it is at it's worst... it's enough to make one think something was mechanically wrong, or rattle the car apart (the instrument cluster literally shakes).
We also are playing with the front suspension. The toe on it makes the steering a little twitchy, and much more likely to try to follow any dips in the road. He also suggested I get a Corvette front bump-steer kit. Some Corvette guys say it's not needed, but in reading up, one Vette performance shop explained just how time consuming dialing out bump steer issues can be (without a kit), it's not just tossing it on a laser machine and rolling the wheels.
Also, I had fun doing a donut on some private property (a warehouse area that is closed on weekends), and did a few hard pulls. It was crazy. Even after the wheels were heated up, the front end didn't come up, but Mike said that it looked like the body came up high enough for the wheels to reach the bottom of the suspension, given how the wheels angled.
Sadly, Mike's phone is an iPhone, and he hates them. So I need to walk him through getting Apple's google drive app installed so he can upload it for me. Or he has to copy it to his computer and toss it on a flash drive.
I still want to get the speedometer gauge and coolant gauge hooked up, right now we're relying on the laptop, or the FAST dash panel.
I think I need to give up trying to repurpose the Turbo Sunbird cluster, and start talking with Dakota Digital about their custom cluster builds to get what I want.
When the weather gets warm enough to do some welding (if needed), we're going to try to install one of the Mini Cooper seats I picked up and see how well it works.
Oh, and apparently my brake pedal switch is broke. My brake lights stopped worker. Fuse is good. So assuming it's that switch.
We spent the highway miles doing some tuning, trying to get rid of the 'chugging' that we would get at RPMs under 2000 (1800-1950) when cruising at highway speeds. This engine likes to run rich. We would bump up the fuel ratio a tiny bit, and the engine would smooth out more and more.
Mike did a light pull, from 60mph he pushed the throttle to 33% and held it there. That part of the VE table was spot on, every vibration in the engine smoothed out where it felt like it was just gliding. It was wild. It also had an A-F Ratio floating between 11.5 and 12.25 during this pull. It seems when the ratio is higher than 13.25, and RPM is under 2000, we get the shuddering/chugging.
So we have a fair amount of time where we need to chase down all of those uncomfortable chugging points and adjust the ratio. Mike said this is just the price of having a performance/race cam, so he isn't sure if we can get it all out, but to explain how bad it is at it's worst... it's enough to make one think something was mechanically wrong, or rattle the car apart (the instrument cluster literally shakes).
Vince, If you are still running the CompCams 232/234 duration @ .050" and .595/.598 lift with LSA of 112, that is a big cam for a 5.7 and larger LS, and too big for the LS4.
It is rated for 2400 rpm to 7200 rpm for a 5.7 and listed as race only... so trying to get it to run smoothly below 2000 rpm on a 5.3 is going to be challenging, if not impossible. The excessive overlap of the camshaft and intake manifold reversion are the primary caused of the issues.
A few things that could make it better. 1. Excessive Valve Overlap: If your ecm allows, adjust the start of injection to be after the exhaust valve closes below 3000 rpm (above this it doesn't really matter). This will keep unburnt fuel from coming into and going right out the exhaust valve and not being used for combustion. With the cam valve overlap pulling fuel out, the A/F ratio will be leaner and it will take more fuel to have good combustion. By only spraying fuel after the exhaust valve is closed, all fuel is used for combustion. This will help idle quality, fuel economy, and power in the lower rpm range.
2. Intake Manifold Reversion: At low cruise rpms, the intake manifold vacuum can exceed the scavenging effect of the exhaust. So as soon as the intake valve opens (while the exhaust valve is open) the exhaust gas is pulled up the intake runner vs into the exhaust manifold. This reduces the available oxygen in the intake charge and hurts combustion. About the only thing that can help is reducing manifold vacuum - On manual cars, upshifting a gear to drop rpm and open the throttle blade, and reduce manifold vacuum helps. Not much of an option for autos.
3. Adjust timing at these cruise rpm and map values to be in the 40 to 45 degree range.
I learned these lessons with my old 224/231 .564/.575 LSA 113 which was too big for a 5.3. This was why I went with 219/223 | .617"/.595" | LSA114+3 with the turbo upgrade and very happy with it.
With a turbo 5.3, you don't need a huge cam to make LOTS of power to 7000 and beyond
Thank you, as always, for sharing your knowledge and experience
Yes, Mike did tell me this was a race cam, and he said similar things, that it was likely never going to be smooth everywhere. I said I was okay with that, just not okay with it being so bad that the instrument cluster 'dances'. lol
He did mention adjusting more things in the ECU than just the VE tables, but since I don't know enough about tuning, I didn't want to assume I was going to remember what he said properly - and I didn't want to put words in his mouth. I'll send him what you suggested and see if that's the same thing he's talking about. He did talk about making adjustments to better deal with the overlap, and that it would be the drive tune versus the track tune. So I *think* you guys are on the same page.
I also discovered today that the changes that Apple made a few months ago, Mike was able to send me the video he took without it being compressed to garbage, so I need to get that on the google drive and link it.
*cough* "The driver" *cough* in this video is not very good at doing donuts, probably bad throttle control. Said driver was really good at getting his last Fiero to kick out a 180 without the front tires moving very much, which is a fun way to turn around in a parking lot.
Okay, so the weekend before last we've been trying to smooth out that last little rough spot in the 70-80mph zone, when the car is "trembling" with the torque converter locked up. I did share with Mike the info that FieroGuru posted and he said we could certainly try those suggestions too.
So we picked a loop that gave us about 75 miles or so on mostly highway driving with long stretches of flat road. This time I drove while he tuned. He tried messing with just the timing first in our last trouble area, advancing it all the way up to 45 at one point, and pulling it way back. It made very little difference. So he set that back to it's starting point (I don't recall what it was) and he played with the fuel next. He tried leaning it out, then adding fuel. Also very little difference. So then it was time to start adjusting both values.
We tried FieroGuru's suggestion first, it got much worst. My vision was literally close to doubling. I don't recall what order he did the next things in, but basically he started trying different combinations, to different degrees of retarded timing and more fuel and advanced timing with more fuel. He would sometimes have me ease off the gas and slow down a little, then go back up to our trouble speed of 70+.
In the end, running the car in that part of the tune with greatly reduced timing and very rich improved the driveability. It's still not perfect, but now it doesn't get bad till about 72. So if I stay under 70, it stayed pretty smooth, except when going up a little incline, which puts the engine load into that same spot that it was hitting at 70+ on flat surfaces.
Here's the painful part of this, before we started this trip, the FAST computer had estimated my MPH at 15.5. For just this circuit, about half of it with this low-timing-high-fuel setting... MPG was down to 8.7! LOL
Mike was like "are you sure you want to leave it here?" and I was like "we can mess with it later, as long as I know what the worst case is for fuel consumption, I can plan accordingly. And I'll just need to buy a second Jerry Can to keep fuel in. He also said we can try to play with the tune to get the transmission to unlock the torque converter at those speeds, or leave it unlocked until it gets up to, say, 75... but damn. That's a lot of extra heat getting generated, and we're already struggling with heat management.
He half-jokingly suggested I buy the Fiero towing kit, so we can put on one of those "cooler holders" on the back of the car and strap jerry cans to that. He still wants to drive my car on RFTH, and said that if he needed to, he'd rig up a pump and hoses to the cans, so he can refill the tank on the fly. I'm pretty sure he was kidding about that part... pretty sure.
Though since most of RFTH won't be in the "lousy spot" of the power curve, the MPG should be much closer to the 15.5. And Mike will dial that in further next. This was just the start of the tuning. At the end he wants to have two tunes, one for regular driving, and one for the track. This one is still "in between" and moving towards the street/everyday one.
This past weekend I went to the junkyard, there is a Fiero that landed there a few weeks ago. The Passenger side seat in it is in great shape, no tears or anything I saw in the fabric, which is rare. Unfortunately the passenger side door is jammed shut, and they had the car up on extra-tall junkyard 'stands', so I couldn't get to the few parts I wanted because I couldn't get enough leverage to break the fasteners loose. Mike said he'd go with me next weekend and bring his battery powered sawzall. I don't like doing that, I don't like damaging parts other people might be able to use. Since this is to get the tube that houses the A/C Orifice tube, and we need to get the accumulator out of the way, and that is easy (and inexpensive) to get new, I won't feel bad about it this time.
Is there a market for good seats? Should I bother to pull it? I have a set of tan leather 84 seats that are in good shape that I've tried to sell locally without success.
Anyhow, this weekend I replaced the power mirror controls (the 'Right' didn't work), and we replaced the auxiliary fuse box in the trunk (which was getting exposed to water and corroding fuses because of the cracked D-plates) with the GEP weatherproof one! When it's done, it'll be mounted facing up, just behind the carpet where the alternator trunk fan motor was, so it'll be easy to access if I need to change fuses. The unused spots are closed up with plugs.
The relay Mike had me get to go along with this is one he used when he was doing motorpool work for the police. He said these 75amp relays could take a beating and he never had one of the TE/Tyco ones fail on him. So that's what we got. We now have plenty of fuse space in the back, and the intercooler pump is wired in with the rest of the key-on stuff. And all the wires running to the relay are on their own eyelets, so if the Amps in the back is too much for that relay, I can pick up a second one. I need to do some math.
Last, does anyone know of a good source to get replacements for the deteriorating material around the hood latch??
[This message has been edited by Trinten (edited 03-02-2025).]
Vince, does the FAST controller allow you to change the timing of the injections (not the pulse width), when the injector opens and closes relative to cam position.
At single digits fuel economy at cruise, that likely means in town it is probably less.
You seriously need to think about a camshaft swap at some point. You should easily be getting low to mid 20s at cruise.
I'm not sure, I'll need to ask Mike. I know there is places where you can adjust duty cycle,
As for a camshaft change, maybe in the future. Right now I am chasing a power number and a 1/4 mile time, and this cam performs insanely well (and smoothly) in the mid-to-upper band. This is not to say that my goals can't be reached with a smaller cam. It's just that I might as well see what we can do with what I have to check other boxes on my list of goals first. I'd had to swap the cam for drive-ability and MPG, and come up 50 HP or Ft/lbs TQ short. lol
Now with how he put this together, a camshaft swap is not tough. Pop off the tire, wheel liner, put a second jackstand under the trunk section, and remove the chromemoly frame rail section, and you have easy access to do that. It's one of the things he designed in. So when we get to that point, it'll be an easy swap. Also, the $300 or so can stay in my "might need a custom radiator" bucket for right now. lol
Once we hit the numbers I'm looking for and we have some fun with it, I will look into going with a different camshaft if we can't find another solution.
It was in the 70s yesterday, so we went for a drive to test the coolant system again. Coolant temps creeped up to 220 from our drive, and we were on roads that stayed at 55mph. Not great. Transmission coolant temp stayed good, never got above 190 to my recollection.
So I'm reaching out to a few radiator companies, telling them what I have and what I need. The AFCO is a two row cross-flow with 1" tubes. We'll see what I can get figured out. Hopefully before the GM Show in Carlisle this year. Otherwise I'll need to see about putting it on a trailer, or not going.
We also hit an issue again with the fuel pump, as the temps came up and fuel temperature came up, the pump was real unhappy and we lost fuel pressure. We could hear the gas boiling in the tank. Apparently that isn't super difficult, 93 octane boils at 100f. But given that my tank was a little more than half-full, we brought about 7+ gallons of gas up to that 100+ temperature mark. This also explains why before when we had this issue, adding fuel was alleviating the problem. The added fuel brought down the temp of the fuel in the tank.
I do have more thermal shielding to put around the headers near the fuel pump, and shielding to put around the pump as well. Next weekend we'll figure out how to mount the temp probe I have near the fuel pump and see how hot the ambient temperature is. Mike suggested we consider a fuel cooler, but where to package it is going to be an issue.
We also looked at how to mount the Mini Cooper seats in the Fiero. Sadly, that's a non-starter. The track system on these seats is a little wild, mainly from how it integrates to the rest of the seat (with a manual lever to lift/lower the seat height). The different in bolt-to-bolt track width is about 2". We couldn't see a way to reasonably modify the seat or swap the tracks from the FIero onto the Mini Cooper seat, not even with cooking up an adapter.
Besides, I put one in the car for a test fit, even with the seat height at it's lowest, the headrest needs to stay in the "sunroof pocket", and once I sat in it, my head was touching the sunroof glass. It also looks like once the interior door trim was on, the door likely wouldn't have closed without squishing something.
We also tried to get the stock Fiero temp gauge wired up. It uses a two-wire sensor, with one wire going to the gauge, the other going to the overheat light (I got it through Rockauto, Manufacturer is WVE, part number 1T1186). The weird half-sliced PICO connector took forever to show up. We found the instrument cluster wiring diagram to see which wires it was at the cluster, then tested them back to the engine compartment to make sure we had the right ones. We wired them up and ... nothing. Thinking we had it backwards, we tried that way, nothing. So we tried the ground-out test (grounding out the sensor wire that runs to the gauge is supposed to make it bury the needle), that didn't happen.
This cluster is pretty beat up and came out of the donor car, so we hope it's just a bad gauge. I'll bring my other cluster from home next week and we'll do some tests before we swap it in.
[This message has been edited by Trinten (edited 03-09-2025).]