I currently have a 89 camaro with a 305 tbi, and I am putting in a 88 GTA TPI in it. I have hte motor all put in and buttoned up, but now I am onto the wiring. I have the computer and the wiring harness from the 88 donor car and need to know how to splice it into the factory 89 harness. I wish the harnesses just plugged and unplugged, but the guy I got it off of, just gave me the engine harness, and nothing else. Does anyone know how to do this or a good website or book with step-by-step instructions on doing this? I am a idiot when it comes to wiring.

 

You would be better off changing your existing harness to match the TPI setup. In '89 GM switched to having the entire car wired in one harness. In '88 they had the engine harness and the electrical harness separate. Not to mention your GTA harness is slightly different than a Camaro with the battery on the other side. There are lots of wiring diagrams on this site you can read. Do you have anyone in your area who can help you?

 

Thanks for the info. I am currently checking out different sites. I wish I had someone in the Chicagoland area to help.

 

Not getting many replies?????? How about this one. I put the 88 350 tpi in the car and hooked everything up other than the wiring harness from my 89. i left my 89 harness in there and hooked up all the sensors, as the plugs are all the same. I have a couple extra plug ends that I am not sure where they go, other than the ones for the smog pump....deleted. My question now is, how do I go about and splice in the 8 injectors into my 89 harness? Do I use the 2 tbi wires? How about the MAF wiring, where does that get spliced into? I really hate wiring so........does anyone need their car painted, in return, wire up my car? I hope i can get the answers. What is the name of that company that makes custom harnesses for the f-bodies?

 

I have a tpi motor running on a tbi ecm (7747) It's an unfinished project so I can 't comment on how it drives, but there is tuning equipment around to make it run well.
My tpi is an 86 and the ecm is 88-91 (?) so for the most part theyplugged right in, but I did have to swap a few wires around and add a map sensor since I didn't get the maf with the motor.

 

Why would you want to run a TPI with the crappy TBI ecm? And how did you solve the single-fire vs double-fire problem? My dad tried to run a TBI engine with a TPI ecm and it wouldnt do anything more than idle. If you touched the throttle it would starve for fuel and die. So he converted the intake to TPI and loved it even more.

 

When I got the motor I didn't get the MAF, and I didn't want to drop $200 on a new one. I already had the 7747 for another motor that I got rid of. I had to add a MAP and move some pins in the connector, but otherwise it seems to run ok. I don't have it driving yet so I can't comment on that. I don't have the O2 in yet.

I will probably be going with an EBL by the time it's all done.


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