Hi everyone! I'm new here. I have acquired a 1986 C4 on trade (for a 2001 Honda Prelude) that was basically hacked up with a 305 sbc, a carb and a mess of hacked up wires. I recently removed the engine and purchased a 1986 TPI aluminum heads engine with 150,000 mi. I have been purchasing wiring harnesses, pigtails, and basically anything to put the car back to the way it is supposed to be. I just got a parts car with no title and busted floor, a 1985 C4, that was partially taken apar,t but has so many goodies like harnesses (some different from my 86 C4), ac box, ac lines, spare tire carrier and spare, beautiful interior, and much more. I just removed the ECM from the 85 with the hopes of cranking/starting the 86. Is this possible with the 86 harness? Should I just search for a 86 ECM? There is so much work i am doing to the 86. I replaced the ignition switch. I purchased the VATS bypass resistors (15pk) and i found 1 that makes fuel pump kick on and starter enable relay click, but thats it. I tried jumping the neutral safety switch terminals, and the starter enable relay as well. It would turn over with the push button setup that was in it before i rewired (the correct way) the car. Im pretty sure I've touched every wire, fuse, and relay that this car has(per following the wire diagrams and tracing wires). I have so much time and effort in on this build and any help would be greatly appreciated!

 

You can’t use the 85 ecm because of the mass air sensor burnoff cycle components.
actually, i suppose u really can, but the 85 has a separate burnoff module that is pure unobtanium.
They were only in a corvette one year, and the next year, the ecm changed to incorporate that circuitry in the ecm.
if you get lucky, the computer is still under the dash on the right side.
if not, hunt around for the computer harness and computer.
the other problem is the prom.
chances are, the new ecm won’t have one.
they are plug and play, and are coded for use.
be careful when you find one, that it’s not a 6 cyl prom.
the vats program is in the prom.
So you have to get the vats removed from it.
Transmission programming is also in the prom .
if your prom is for a stick, the converter lockup won’t work.
if your prom is got an auto, and you have a stick, the trans won’t go into overdrive.
simple stuff, but lots of gotchas

 

Thanks for all the great info! I do not have the ecm for the 86 anymore. I am searching for one. If you know of anywhere I can purchase one from please let me know. Thanks again!

 

Have fun with your 86..I do with mine.Your having a Alum. heads means its a late year 86 c4.

 

Check the camaro forum.
people sell ecm’ and tpi parts on there pretty cheap

 

^^^^3rdgen.org is a good site...tpi parts are way cheaper there.

You can run a WTB ad here in the C4 parts section. Bet somebody here has one.