Hello all. I have a 92 rs v6 car. I just recently traded for a 89 350 tpi and the engine harness from the c100 out and ecm. It's all installed now. I had to make some pinout changes on the c100 for the wipers but I think everything else is working. The engine will spin over and is firing but the injectors are not working. Have good fuel pressure and plug spark. This is my first tpi engine and I will admit to being ignorant to how it all works. I need help. Any advice is very appreciated. I don't know if I need to maybe make more pinout changes or maybe something else. Please help.

 

89 TPI is a MAF setup. The 92 3.1 V6 uses a speed density setup and 730 ecm. You'll need to either source a 90-92 TPI harness, or convert your V6 harness over to the V8. Its relatively straightforward to convert the V6 harness. You have to splice in two injectors and rearrange some of the accessory wiring. There are a lot of differences in the connectors between 89 and 92. It would be a tremendous headache to make that 89 harness work in your car.

Here's the thread where I've been doing the same swap:
https://www.thirdgen.org/forums/memb...ird-build.html

-cal30_sniper

 

I really don't mind any amount of work. I'm sure you are right about it being a pain, but do you know what changes need to be made. I'm used to just simply using hei and a carb, but I want to make this tpi work. It's a strong running engine.

 

Using a noid light, check to see if the injectors are pulsing when cranking. If they are pulsing, but not firing, then it is an injector issue. If they are not pulsing, then check your engine harness' grounds. Just to clarify, your now running the L98's MAF ECM, correct?

 

I have the whole harness from the firewall out and ecm from the 89 car. It all worked in the 89 but I think my problem lies in that my dash harness is a 92. I'm hoping someone knows what the differences are and can tell me what changes to make. Thank you all. Any help is better than none.

 

Any help is better than none lol? First of all, I have no idea how you were able to connect your stock ECM terminals to the '89 ECM, but you said you did, so we'll just leave it at that. Second, your running an '89 ECM that is setup for its' own distinct VATS signal, while at the same time running your stock '92 in dash wiring with stock key and signal. You now say your injectors aren't firing? Hmm, I wonder why...

 

Ok here's the deal. The 89 engine harness or my 92 harness for that matter comes out of the firewall and splits in many different directions eventually going under the air box into the right front fender and back into the car behind the right hand side kick panel. That's where the ecm plugs up and that's how I did it. If I have a vats issue that helps a lot. Do you know how I can fix it? As I said before I'm a novice to tpi even though it's out dated and obsolete I like it.

 

This is why I asked you to verify with a noid light that the injectors are being pulsed. If they are, yet aren't firing, then they are more than likely Multec injectors, and if one shorts out, then they all short, and you will need new injectors. However, if you are confident the engine ran fine before getting your hands on it, then chances are the injectors are not pulsing, and it is either a ground issue, or how you wired the ECM. VATS will essentially kill your fueling unless it recognizes the key signal. Try disabling vats and see if the engine starts, and if you don't know how to disable VATS, search it on youtube, there is a directional on there that will walk you through the whole process...

 

VATS is very likely a contributor to your issue. You will need to disable it as Street Lethal suggested. However, even with VATS disabled, you are still going to have major discontinuities at the C100 connector (near the steering column on the bulkhead), and the C207 connector (under the dash by the ECM), both of which are joints between the engine harness and the dash harness. The pinouts have many differences between 89 and 92. Some pins are used in the 89 harness and not in the 92 harness, and vice versa, in both locations. Short of buying new connectors and completely repinning them (which even then might not work), you're going to have a very difficult time getting them together. For instance, I only have picked apart 88 and 92 harnesses, but if the 88 and 89 are anything alike, you should have two sets of wiper controls now wired in (the 88 has wiper motor controls in the side of the C100 connector that goes to the ECM. The 92 has them in the side of the C100 that goes to the headlights, turn signals, etc. That's just one example of many differences. Keep in mind the 92 dash harness also has 3 connectors going to the ECM, whereas the 89 ECM only has two connectors. How did you deal with that issue?

It is far easier to take the 92 V6 harness you should still have and make it work with the V8. You will also have the added advantage of then keeping the Speed Density system found on the 90-92 cars. If you follow my method, you will need to cut out the injector harness, TPS, IAC, and alternator wiring from the 89 V8 harness. This will need to be spliced into the 92 V6 harness with added length to reach components that move from one side on the V6 to the other side on the V8. You will also need to extend the wiring for the knock sensor, and possibly the 02 sensor depending on what headers you are running on the V8. Throw a V8 memcal and prom into your factory V6 computer, and you are good to go. WAY easier than trying to mesh together the 89 and 92 harnesses (if that's even possible).

For reference (just start counting the differences, I stopped considering splicing mine when I hit an entire notebook page full of them):
1989 C100:


1992 C100:


1989 C207:


1992 C207:


Don't feel bad. This is a very non-intuitive problem. I have been messing with 3rdGens for nearly a decade now, and it was only a few months ago that I realized there were such massive differences in the bulkhead connectors through the years. What GM was thinking, we'll probably never know.

-cal30sniper