MY 85 IROC RECENTLYCAUGHT FIRE AND DESTROYED THE VERY HARD TO FIND ENGINE HARNESS, MY LOCAL CAMARO/ FIREBIRD PARTS GUY SUGGESTED I REPLACE IT WITH THE 86-88 SETUP WHICH IS STILL A MAF AND COLD START SYSTEM, BUT MUCH MORE COMMON.HAS ANYONE EVER SWAPPED OUT AN 85 IROC TPI ECM AND HARNESS AND REPLACED IT WITH 88 TPI ECM AND HARNESS? IF SO WERE THERE ANY TIPS, TRICKS, OR TREATS I SHOULD BE AWARE OF?

 

I swapped my 85 out for an 87 harness, 165 computer (86-89 MAF), and also converted it to the 89 setup without the cold start injector.

The swap is really easy. I've heard that the 88-89 harness has more crap on it because the chassis & engine harness is integrated, but I never pulled the harness out of my 88 so I can't verify. It's at least something that you will want to investigate, or just stick with an 86-87 harness.

Anyway... I used an 87 harness. In 87 they went to a small cap distributer, but I converted my distributer as well, so I didn't need to change it. I did notice however, that the large and small cap distributer use the same 4 wires. It's just the harness plug that is different. You can buy an adapter, or you can buy the proper harness plug and re-pin the wires.

The 87 harness is set up for 2 cooling fans. Just determine which one is the main fan circuit and plug that one into your fan.

There was a black wire in the harness that was designed to attach to one of the studs on the starter solenoid. Since my 85 harness didn't have this, I just tucked the wire into the harness and didn't use it.

The only hassle was the bulkhead on the passenger side kick panel. You'll find that the 86-89 bulkhead is approximately 1/4" wider than the 85 bulkhead. I used a die-grinder to open the hole up 1/8" on each side, then the bulkhead fit perfectly.

Under the dash, the new computer was a direct fit in the old bracket, and all of the under-dash plugs plugged in perfectly.

If you have any common sense at all, and are even somewhat mechanically inclined, this should be an easy swap.

The only thing you'll need to pay attention to is what chip to use in the computer. I burn my own chips, so this wasn't an issue for me, but you need to make sure that you either get a custom chip as well, or get the one that best fits your application. You're already aware that the 89 eliminates the cold start injector, so if you decide to retain that, you need to pick a chip from 86-88. Since you have a 305 automatic (if the engine is stock), you shouldn't have a hard time finding a used chip.

 

when i bought my car the harness was all cut up and what not had more wire nuts on it then most home electrical jobs, i decided to go with the painless kit because i could not find a used harness in my area. THE PAINLESS KIT IS NOT PAINLESS and if you do decide to go that route do yourself a favor and buy the extra length, it just makes things easier, there is also a sight about repinning the harness for all the different TPI models MAF and SD, so at this point if you could find a used 86-89 harness and a SD computer you could change it over

just throwing out options i wish i wouldve know before i did my project
good luck
matt

 

I agree that the Painless wiring harness is not a no brainer. For $325, I expected it to be very well laid out, with exhaustive instructions. Painless decided to make their harness use a very hard to find part # oil pressure send unit. There were also a few wires, ie the pink/black ign wire, that the instructions gave very vague instructions of where/what to connect it to. Since you are replacing a factory harness, not retrofitting a carbed engine to TPI like I did, I'd listen to the above advice and find a factory harness and chip that will work for you.

 

Hey guys Im doing a Painless wiring setup from a 86 carb to an 89' TPI. Can you guys help me out with a few things? One is that i have a brown wire going to my VSS but im told that I need 2 wires so the computer sees the voltage to and from the VSS? Also, i have the oil sending unit /switch that goes to the side of the block over the oil filter adapter and is cigar shaped with 3 terminals. Well i just wanted to make sure that when you guys did this install that you had to run a wire (brown/white) to the fuel relay as well? the other 2 wires are orange and blue(I think). And the cooling fans also, i have a green wire that goes to Computer ground. I dont have the wiring that goes from the fans to the sensor in fron of the manifold. Can you guys give me some Insight?

 

Not hard to find at all, I have an extra one in the garage gathering dust...complete with ECM and MAS module.

 

THANKS FOR ALL YOUR RESPONSES, FORTUNATELY I DID GO WITH THE 86-87 HARNESS SETUP AND JIM, EVERYTHING YOU FOUND I HAVE FOUND WITH MINE EXCEPT I STUCK WITH THE ORIGINAL DIST. AND REPINNED THE WIRES TO THE ORIGINAL PLUG. MY PROBLEM SEEMS TO BE THAT MY FUEL PUMP WON'T RUN UNLESS I HOT WIRE IT. ALSO YOU ARE SUPPOSED TO BE ABLE TO PUT 12v TO TERM. G ON THE ALDL CONN. AND PUMP SHOULD RUN, NOT MINE. THE ONLY THING I'M NOT SURE ABOUT IS A WHITE PLUG WITH 2 PINK WIRES AND 1 BROWN UNDER THE DASH WITH ECM PLUGS. I BELIEVE THERE MIGHT HAVE BEEN SOME TYPE OF SILVER BOX FROM THE 85 ECM CONNECTED THERE, SHOULD IT STILL BE HOOKED UP THERE?
ANOTHER THING IS I NOTICED THE OTHER DAY IS THE ECM THEY GAVE ME SAYS IT'S FROM AN 89 VETTE, COULD THIS BE A PROBLEM?
OH, BY THE WAY, DID I MENTION THAT I HAVEN'T BEEN ABLE TO MAKE IT RUN YET? ALMOST STARTS BUT NOT QUITE. FUEL PRESSURE IS ONLY AT 29# WITH POWER ON SO I'M ABOUT TO CHANGE THE FUEL FILTER AND SEE IF THAT HELPS.

MORLEY, I WISH I WOULD HAVE FOUND THIS SITE EARLIER. BUT JUST OUT OF CURIOSITY, WHAT WOULD YOU TAKE FOR THAT 85 SETUP??

 

Ok, the "extra" connector by the ECM is for the MAS module found on 1985 TPI's. The module controls MAF power and burn off, on the newer MAF's there were 2 relays for those functions.

I paid $110 for the 85 harness, ECM and MAS module, so that is what I would sell it for. The harness is complete (not cut up at all) and the ECM/MAS module are known to work. I repinned my harness and installed a 165 ECM a couple years ago because I put a built 350 in the car and needed an ECM that had better support for prom burning.