94-95 motors have a crank sensor behind the harmonic balancer and a cam sensor in the top of one of the heads. That being said, it is possible to run these motors with the 91-93 (OBD1) ECM and simply not use those sensors. You will have to verify whether or not they are in use.
I am running a 91-93 crate motor with the 91-93 ECM, but have all of the upper intake and accessory stuff from a 94 motor. It's easy to end up with a mutt on these motors, as several parts from all years will mix and match.
Thanks for the reply...with this info and the pics above I think I can figure it out..
I have a couple of specific computer questions involving my swap. I placed a 92 crate DOHC with Isuzu transaxle into my 88 4 cyl. coupe. I have the 1614939 ECM with BCFA Prom.
1. Is the EGR operation dependent on vehicle speed? I failed my smog inspection due to hi NOX at 15 MPH. The EGR valve works properly ( opens and allows exhaust gas flow) when manually forced to actuate. My scanner says I have no EGR at 15 MPH.
2. I am currently sending the ECM speed sensor input from the Isuzu at 4000 PPM. Is there a way to make this the 24000 PPM the ECM wants to see? My scanner reports I am traveling at 10 MPH when actual speed is 60. I suspect this is also affecting fuel mileage and I randomly set a code 24 speed sensor error.
Thanks in advance for all replies,
Larry San Diego, Ca. 88 3.4 DOHC 85 3.1 Stroker 87 Stock Coupe.
Robert, Perhaps I did not explain the problem with enough detail.
My speedometer is working properly. The ECM is reporting to my OTC data scanner 10 MPH when vehicle speed is actually 60. I feel this is because the ECM wants to see 24000 PPM and I suspect the EGR is not activating correctly because of the apparently lower ECM sensed speed.
Is the EGR dependent on vehicle speed for proper operation?
After much personal debate I am now installing the 3.4 DOHC from my old 96 GTP into my Fiero, I am keeping it Auto. Will be going with boost. Was considering a twin M90 setup but like many over at RFT have expressed it would be better to just go with a T4 say 60 trim for boost.
Been reading these pages all week. Thanks for all of the info that has been made available.
I have a 91 3.4l DOHC mated to a 5 speed. When cranking, the engine drips oil from the rear of the engine oil cooler. I replaced the gasket on the oil cooler to block mating surface with one from an oil filter. I just installed this engine so this was the first time I tried to start it.
A couple of questions:
Does anyone know of the correct GM part number gasket?
Given that the oil sending unit is part of the of the engine oil cooler, is it possible to remove the oil cooler somehow? I have removed the oil on a 2002 push rod 3.4L replacing the cooler with a threaded fitting from GM but the oil pressure sending unit was not part of the assembly.
Has anyone else had problems with the engine oil cooler in the twin cam V6 leaking? What was the cause/how did you fix it.
It would seem the gasket I am using is maybe not a good fit? Maybe not the same diameter as the original gasket that was supposed to be there or to thick (getting crushed) too thin?
Yeah I looked at that thank you but would you post a pic of your setup without an oil cooler? A picture of the oil pres sending unit would be helpful. Where the sending unit should plug in (without the cooler) on my block, would hit the rear AC bracket, on my engine.
Sounds like I might be able to get the parts I need at a junk, assuming the oil filter threads screw in on the non-oil-cooler blocks.
Yeah I looked at that thank you but would you post a pic of your setup without an oil cooler? A picture of the oil pres sending unit would be helpful. Where the sending unit should plug in (without the cooler) on my block, would hit the rear AC bracket, on my engine.
Sounds like I might be able to get the parts I need at a junk, assuming the oil filter threads screw in on the non-oil-cooler blocks.
Yes the filter will screw to the block just like the 2.8 but you will need the hollow screw, if you are replacing the ICM from the Stock location the block may have an access to oil pressure on top of the starter like the 96-97. Or just find the sandwich type oil Filter adapter that the 94-95 uses, some other models use it too.
I have been reading thru this thread as I am going to be doing a 95 SFI DOHC swap in my 88 Fiero with a Getrag transmission.
Since I hope to keep this car as a daily driver, I plant to keep the engine basically stock. My first question is with the motor mounts.
I understand stock 88 mounts will work but the engine could sit a bit lower lower with the Dodge truck mounts. My car is an 88 Mera. The decklid sits higher than the Fiero decklid due to the bodywork. However the decklid hinge is different. Has anyone installed a DOHC in a Mera using the stock 88 mounts? I plan to build the swap on a spare 88 cradle but want to make sure the engne will clear the decklid and hinge when I install it. I also saw where the lower part of the passenger side hinge mount needs to be trimmed for engine clearance.
My second question concerns the dog bone. Since my car is an 88 it does not have the shock damper mounts that some people have re purposed for an additional motor monnt. I have read where people have broken the timing cover using the dog bone. For those that currently use the dog bone, what did you do to keep this from happening?
I was looking for information on rebuilding a 5 speed getrag and I stumbled across this thread about the 3.4 engines. I have 3 that I am wanting to sell. One is good and runs, the second is for parts and the third will not turn over. There are a lot of parts with the engines and the engines are complete. I acquired these on a big parts purchase and I do not know the first thing about doing an engine swap. If anyone is interested please contact me. Thanks Pat
I was looking for information on rebuilding a 5 speed getrag and I stumbled across this thread about the 3.4 engines. I have 3 that I am wanting to sell. One is good and runs, the second is for parts and the third will not turn over. There are a lot of parts with the engines and the engines are complete. I acquired these on a big parts purchase and I do not know the first thing about doing an engine swap. If anyone is interested please contact me. Thanks Pat
My build progress.... (keeping the thread alive too)
Engine is nearly ready to be dressed in accessories and wiring. Painted my valve covers and intake with red VHT wrinkle finish spray paint. You lay the paint on in three layers spraying horizontally for the first coat, vertical for the second, and diagonally last. I was hoping for more wrinkle but I like it overall (wrinkle shows up better on camera IMHO)
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My car and the victim, 1988 GT 2.8 5 speed. 162k miles and in desperate need of paint. Mods include alarm/keyless entry, double din bluetooth stereo, autodim mirror, 20% tint, tinted sail panels, 17" Eagle alloy rims, lowered up front "raked look" with Rodney lowering balljoints, stainless steel Ocelot exhaust, Fierostore scoop, trailer hitch, and probably a couple more things.
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Current thoughts in my head about the swap: 1. How I am going to build the exhaust y-pipe 2. How to do the fuel line and coolant routing 3. Dipstick placement 4. Where to locate rubber grommets for the valve cover bolts 5. How its gonna sound at 7k rpm 6. Did I tighten the rod bolts? J/K
Backstory for the swap: For the longest time I didn't know what engine swap I wanted to do but I eventually started leaning more toward a 3.4 dohc swap for the fun factor with the 7k redline and getrag, plus it was a bolt in deal with minimal mount fabrication and clutch/flywheel issues. So I was waiting for the right engine or donor car to come along and while searching craigslist I found a wrecked 1992 Lumina Z34 and ended up getting it for $225. I took the engine, ecu, and wiring and scrapped the car for $155 ($70 invested to start). I stripped the 3.4 dohc block down bare and had it cleaned, brass freeze plugs installed, and cam bearings replaced at the machine shop. The machine shop also did a valve job to the heads and machined them. Over the last year I slowly bought or gathered parts, planned, and assembled the engine. Some of the higher ticket items were a Spec Stage 2+ clutch $380, Erik's wiring harness $370, Sinister performance chip $168, machine work $500, 97 intake swap parts $100, Rodney decklid gas strut and FWD getrag conv parts $160, FWD getrag $200, custom a/c hose (2002ssconv) $125, and I haven't totaled my parts for the engine but what I can remember: (bearings, rings, full felpro gasket kit, timing belt kit, timing chain kit, timing belt tensioner (luckily found NOS), reman alternator, new v5 compressor, water pump, p/s delete idler, serp belt, flywheel, thermostat, misc sensors, engine paint(s), and oh yeah the 3.4 DOHC Kent Moore service tool set off ebay for $120 SCORE!.
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Also in the last year my wife and I welcomed our first baby into the world, a healthy 6 lb 6 oz girl named Charlotte. Her and me pictured:
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[This message has been edited by 88cryan (edited 08-14-2017).]
For the dipstick, I used a Fiero V6 one. Straightened the bottom part of the tube and bent the tube so that it just showed over the front head. Marked new fill/full points on the stick (just drilled very small holes) but it fits right in there and worked fine. You can see what I did for fuel lines and coolant routing on my web site, probably easier than me trying to explain here. For the exhaust, don't make it the way I did (see pics on web site). It was too close to the a/c hookup point on the side of the engine bay so I had to modify the a/c hookup (direct connect to the hard lines) and that caused no end of problems that I never really resolved.
------------------ Anything I might say is probably worth what you paid for it, so treat it accordingly!
I am putting a 96 DOHC in my project as well. I just went through a bunch of work to get an exhaust system on to the engine. The 91-95 can use the front exhaust manifold on the rear head and turn it over with a bit of work but the 96 up can't. The exhaust ports just don't line up at all. If you want to run the stock Fiero exhaust route you need to do one of two things. Block off the oem exhaust pipe route off the rear manifold and build a custom cross over to match up on the front side, or build a custom set of headers to remove the oem exhaust pipe location.
I started down the custom exhaust route by building oval to round connector pipes off a set of header flanges I built but it was getting pretty complicated pretty quickly so I opted to use the oem and run a very short exhaust system to get the car on the road. In the future, I may go back and build a set of custom equal length headers and cross over to run the Fiero route but I doubt it.....
There really isn't much room in behind the engine when you keep the trunk so you have to be crafty in how you build your system. I am using a 2.5" system so I bought a couple of the really tight exhaust donuts for tight curves off the exhaust manifold and added a flex joint, high flow catalytic converter and a Thrustmaster muffler. Had to cut some of the muffler out to fit in against the cradle and also used v-clamps to help with putting the exhaust in when in the car. Not enough room to push pipes in and clamp in there....
Another way to route the exhaust which gives a bit more room is to wrap it around so that the exhaust pipe comes down in front of the engine cradle rear frame cross piece and then out through the oem Fiero notch in the rear cradle frame cross piece. There is a pic or two out there showing that routing as well. I had the cat in mine to help with the noise a bit so I did not feel I would have the room needed to run that route.
A couple pics if I can get pip to work....
Side that faces the trunk. You will see that the route is quite tight
The front side. You can see the section that needs to be cut out for the fitting in the tight area.
Another item it looks like you have the power steering pump delete pulley only in the top hole of the bracket. You will find that this will fail pretty quickly once you get he pressure from the belt tensioner. Ltlfrarri shows a great way to build a plate and pulley holder so I highly recommend doing that.
Thanks for the tips Don. I'm actually using the 92 Lumina engine with the 97 intake parts, so I already purchased another front manifold for the rear. I'm gonna keep the stainless ocelot system even though it is 2 inch (might give a unique sound with high velocity) so i only have to build a fiero style y pipe.
As for the p/s idler I did read about a failure of the timing cover with it in the top hole, so I changed it. I tapped the middle hole where the cover is thick and strong and now have the idler there (don't have a picture with the change). For anyone reading this required the use of a shorter belt, the 710k6 that fits a 1994 Lumina 3.1 among others.
I am putting my '91-'93 wiring harness on to my '96 engine and have a couple questions. First, I am putting the older OBDI harness on because I have it already and I can't find an OBDII harness right now. I fully intend to put an OBDII wiring harness and PCM in place later but I just want to get the car running for right now.
Questions: 1. I have traced all my sensors through the harness to confirm I am correct in my sensor guesses. I have everything connected except for a couple sensors. a. I have a two pin sensor connector that I am not sure about. I think it might be for the coolant low level sensor but I don't know where that would be on a '96 engine b. The other option it might be is the mat sensor connector? The sensor that sits in the intake tube from air cleaner to throttle body. c. I have seen reference to these but I have not actually seen any pictures of them? d. Is that senor handled in a different manner on the '96 engine?
2. Does the alternator power wire go to the electrical block on the passenger fender well below the C500 block or does it wrap around to the power connector on the starter? a. I know the main battery power connects down to the starter as well in the Fiero but I plan to make a connector station in the passenger fender well where both my power and ground from the battery up front connects and then distributes from there so I could just run the alternator wire over to that connector rather than to the starter?
3. MAP sensor a. I see reference to the MAP sensor on '91-'93 engines and the '96 engine uses MAF on the throttle body. b. Do I need to wire up a MAP sensor on the '96 and if so, where as I don't have any sensor wires left to connect to something like that???
I think that should do it for now but I am sure I will be back asking more questions soon.
Traced all the wires and found all plug homes except for one that goes past the starter along with the VSS, reverse and oil temp sensor plugs. I think it might be the MAT sensor that goes into the intake tube. I also do not have any plugs for a MAP sensor in my harness made up by Erik so will assume at the point that it is not used? Will need to check out the wiring bundles again today to make sure but not seeing anything so far.
I am also looking at evap canisters etc. Does the 3.4 use the old Fiero evap canister or do you guys put in the 3.4 canister as it is a bit larger? Also, where would the hoses come from on the 3.4?
Sorry for all the questions but you think you have everything read up on and figured out right up til you go to piut it in and find all kinds of remaining items that need answers....
Found the last connector. It is a MAT sensor so need to add that to the intake tube coming from the airbox.
I think I am close...... :-D
I ended up having a problem with the alternator. I have the '96 engine of course so the harness was set up with a '91-'93 harness set up for a '94-'95 engine that I had started with. I am now working out the alternator. I ended up needing a '96 alternator as the earlier ones do not mount the same way. Unfortunately, GM changed the pigtail on the next gen alternators so needed the new pigtail mapped into the older harness.
My latest question.
I have the pigtail sorted I think but have a question. The red #1 wire still goes to the inline fused power feed and I believe I have the third wire identified as the feed to C500 B3 which goes to the dash charging light. In the '96 wiring harness, there is a supplied power feed on the 4th pin.
Is this a required power feed to the alternator? The older alts don't have it. The 3rd pin of the '96 wiring harness goes to the pcm vs the older going to a powered charge light in the Fiero through B3.
Hope someone has some feedback as I think that is my last question to get the wiring harness buttoned up.
This swap has been on my radar since Darth swapped one into a yellow Artero that I saw at a local Fiero show. That sound alone has me giddy. It's a 60k mile motor from a 97 Monte. Right now it'll be going in pretty much bone stock. I'd like to add headers and a custom short runner intake in the near future and maybe a turbo further on down the line. Here's a bit of a snag I've run into. I've done a number of 3800 harnesses and the hot temp lamp has been driven by the ecm. There is no provision for a hot temp light on this ecm. It looks like the lamp is controlled with a module of some sort in the instrument panel, according to my alldatadiy scematics, which has me wondering how this has been handled by everyone else.
[This message has been edited by Dave E Bouy (edited 01-07-2021).]
...There is no provision for a hot temp light on this ecm. It looks like the lamp is controlled with a module of some sort in the instrument panel, according to my alldatadiy scematics, which has me wondering how this has been handled by everyone else.
I'm not that far along with mine, yet. But keep in mind that in the stock V6 Fiero, the "hot" lamp (and the temperature gauge, for that matter) work entirely independently of the ECM. It's a single sender that drives the gauge, and turns on the light. (It's the one on the corner of the trunk-side head, under the coil.)
Mine is in and running after way too many years. I do need to drop it again as the rear main seal I forgot to change before putting into the car is now leaking. Car runs and I drove it before I put it away for a couple months while I do some long overdue work on my wife's Miata....
Cheers Don
It is in this project
[This message has been edited by 355Fiero (edited 01-09-2021).]
I'm not that far along with mine, yet. But keep in mind that in the stock V6 Fiero, the "hot" lamp (and the temperature gauge, for that matter) work entirely independently of the ECM. It's a single sender that drives the gauge, and turns on the light. (It's the one on the corner of the trunk-side head, under the coil.)
Good to know. I thought I would be clever and use a 3 pin temp sensor from a GTP. Was making the wiring harness when I discovered that there was nothing in the ecm to drive the hot light.
[This message has been edited by Dave E Bouy (edited 01-10-2021).]
Good to know. I thought I would be clever and use a 3 pin temp sensor from a GTP. Was making the wiring harness when I discovered that there was nothing in the ecm to drive the hot light.
I also forgot. The 4.9, as installed in the caddy, comes with a switch that screws into the rear head, IIRC. Supposedly that is for a the temperature light. I have no idea what the off/on temp is, however.
Hey yall, just picked up an LQ1 from a 1997 chevy monte carlo. I have been looking into doing this swap for a while and finally found a good deal for one. $270 but I had to pull it myself.
I do have a question about the timing mods. What amount of timing can be done without affecting drivability too much? I have heard of the 6/6 timing mod and the 13 degree timing mod, with people saying the 13 degree one makes the car undrivable, but I havent heard much about the 6/6 degree one.
[This message has been edited by Xenoblast (edited 10-20-2022).]
Can anyone provide this overall/maximum width dimension, please? I've looked through all the 3.4 TDC topics, as well as in every corner of the web and have had no luck. If you are willing to take a few more (max height, from bottom of oil pan to top of intake, or crank C/L to top, too), that would be much appreciated. Not going into a Fiero, but the engine bay I'm working with is 21" wide in the middle ( as in, mid block height or so), and does get wider as you go upwards, but maybe 28" max of width. I should have 24" of height to work with, maybe more. Front to rear (going in a RWD setup) should be okay clearance wise, but that (even rough, rear block face to timing cover up front) dimension would be very helpful, too. TIA.
