Here's my dilema: I have an 87 IROC 5.7 that I'm swapping a fresh powertrain into that I rebuilt from my old 89 TA. I also have the complete harness and powertrain for an 89 GTA. I have access to all parts for both model years, and would like the best of both worlds......Passlock, the 89 intake setup, 89 serpentine setup, use the 89 computer, etc.

So far my best option I believe is to shop the 9th injector off the existing 87 harness, use the steering column and Passlock box from the 89, 89 ECU, swap over the accessories,.........lots of holes in this train of thought I'm sure, but I have never dived into one of these cars too deep yet, and don't know how everything is linked together.

Any thoughts, ideas, comments, suggestions, would be appreciated.

 

The '87 ECM and the '89 ECM are both the 165 ECM. The memcals are different. The harnesses are nearly identical, except for the fact that the 9th injector was elimenated for the '89 car, and the altenator & AC compressor is switched from side to side due to the serpentine setup on the '89 car. I have always wanted to switch to the serpentine setup on my '87 car, but have not done it yet. For me, I would simply splice and extend the altenator hookups so that they can reach to the other side of the engine. I have removed all of the AC stuff, so thats not an issue for me.

You could simply keep the '87 harness if its still installed into the car that you will use the '89 stuff and make the mods for reach in the '87 harness.

 

That seems like my plans so far. My main concern at this point would be with the Passlock. How would the 89 computer react to not having a Passlock box and the wiring/relay to the starter?

Also, in 89 the GTA cluster was all electronic (not the digital one), and the IROC will be a mechanical speedometer in 87 correct?

Thanks for the reply Doc.

 

I got the Camaro to run with the 9th injector deleted while using the 87 memcal, and everything else is in working order. I tried the 89 memcal and the engine cranks, but gets no fuel. I assume the VATS is not allowing the injectors to fire. Thoughts?

Thanks

 

You are correct.

RBob.

 

To get passed this could I merely run a 12V wire from an ignition switched source to the (B6 pin I think) ECM to simulate the "go" signal from the VATS box?

 

Won't work. Look on the 'net for a VATs eliminator box. Or get into PROM tuning and turn it off via the option flag.

RBob.

 

I've seen all that stuff, but there has to be a simpler way to do this. I'll let you know what I experiment with. Thanks for the replies.

I will get into tuning this system eventually, but for now I'm keeping it simple trying to get all systems 100% before I do any serious modifications.

 

www.tbichips.com give brian harris a call,he can burn you a chip with the vats disabled.

that way you can get the car running and get into the chip burning later.

 

I am telling you the way it is. Good luck with your 'other' attempts.

RBob.

 

^I'll take your word for it. hah
Might as well just buy the tuning stuff now anyhow. Car runs ok with the 87 stuff other than the carblike startups. Thanks again.

 

I ran my 86 with software from an 89, but , like stated above, I did need to disable the vats in the chip.
Car ran better with the 89 software than it did with the 86, but that car had problems that the software couldn't fix.

 

Well, we (special thanks to graebZ28) got it to work with the 89 stuff by wiring in the VATS box and using the key (temporarily) to make the box happy. If I get it wired in solid and everything continues to run well I suppose I'll to a write up on it if there's nothing out there like it.

It definitely runs better with the newer tune file.