I have been trying to find out will an 86 305 TPI Harness and 86 TPI ECU will work with an 89 Body and 89 TPI motor and I have got two opposite answers.

One of the people from this website said that 86-89 it WILL work.

Another person said that 86 WILL NOT work because in an 86 harness there are 2 seperate harness's (in which there are).....and in 89 it is all one inclusive harness and that I should stick with 87 -89.

Which one is correct because now I have wasted my money based on information from this site that does not seem to be correct.

 

I put an engine in a friends '89 L98 IROC and from what I recall there were two harnesses. One for the computer sensors/fuel injection and the other for the engine sensors/starter. I think there was a plug near the back of the engine that connected the two so some signals could be shared between harnesses.

'86-89 use the same computer and are MAF sensor based. '89 doesn't use a cold start injector but thats not a big deal. I would think you should be able to get an '86 harness to work.

 

Just remember.....This site is comprised of ENTHUSIASTS & not a business site.

Despite the vast knowledge contained here, there is , and always will be, the potential for bad information to be passed on.

Gather several opinions & compare answers, then make the final decision yourself.

Sorry if you made a hasty decision, based on your initial information. Good luck.

 

I would hazard a guess that at least 90% of the time, information from this Board will save you money, not waste it.

'86-'88 TPI systems were basically the same. '89 was the last year of the MAF system, and it did not have the cold start injector so it would be slightly different than the preceding 3 years. '90 was the first year of speed density, so the '90-'92 harnesses would be much different from '86-'89.

 

Listen up.....

'86 & '87 will only work in in those years.

Those will not work in an '89.
You must have an '88 or '89 for an '89 car.

 

Expense aside I wouldn't consider using an '86 ECM because of it's slow processor and output data rate. In any case if you have the '86 harness and ECM what is the actual problem? You do have a problem, right? I assume that's why you're asking the question.