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.

Another productive weekend!

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.

quote Originally posted by Trinten: -Replace the orifice tube and pull vacuum on the AC system to make sure it holds.

Use a variable orifice valve instead of a fixed orifice tube. That will give better AC performance at low engine speeds and low vehicle speeds.

Thanks Will.

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.

Thanks guys!

quote Originally posted by Trinten: 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).]

Some good progress today!

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.

Bob

A mixed Saturday.

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.

We found a workaround for the transmission issue!

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!

Thanks!

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.

quote Originally posted by Trinten: 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.