I guess I was a little confused about wiring harnesses... is the ECU and gauge wiring all one? To get the computer wiring harness out do you have to take out basically all the wiring in the car? Like today I wanted to take out the headlight wiring harness... but I guess there is no such thing as that and it is all attached into the main wiring harness?
Thanks,
Douglas

 

What kind of car is it?
I rewired my complete car--an 86 T/A--now it's an undercover 89--when I was pulling everything out-it was all connected--like the engine harness was in one huge loom that went into the firewall plug--so everything under the hood(from my expierence)terminates into that big plug--which you unscrew from the firewall--2 bolts I think. It then continues into the car itself. The only plug I found that breaks up the harness is the tail light harness that unplugs over the driver side rear wheel(on the 89) on the 86 there is no plug. All the gauges are wired into the harness that goes into the ecm--some of it anyway. Also the ecm harness goes into the engine compartment--to the sensors.

 

I removed the computer from my '86 Z-28 and it is ONE harness. The harness that you "need" comes out from the drivers side firewall. Right beside the brake booster. The harness that goes to the ECM comes out of the passenger side front fender and goes to the engine sensors and dist, and TC lockup, and carb (i think). But on my car....yes, it is 2 seperate harnesses.


Hope this helps :lala: :rockon:

 

Again-I think it depends on the car itself--mine was a tpi bird. There was a seperate harness for the ecm--I got to it from the fender vent on the pass side--but--if I remember correctly--it was wired into the dash harness too--besides the motor harness.

 

Cool, thanks guys! It is a 84 TA LG4, but I want to go TPI and since I have the car ripped apart already and the engine runs w/o the ECU so I would rip it all out now.
If I was going to wire it, should I go w/ the aftermarket (Painless) wiring for the TPI and like another aftermarket wiring harness for the headlights etc?

Thanks guys!
Douglas

 

I just ripped the wiring harness for my 86 IROC out, needed to clean up the engine bay a little more. Since my car used to be TPI, and theres no chance it will ever be again, I decided to do away with the wiring harness. Now there was a whole bunch of wires in there, all old injector plugs, sensor plugs etc., none of which I needed any more. It turns out I only needed 4 of the wires that were in that harness. One was power for the electric fan (which you really dont need that, you can always hard wire a switch, or just wire it so it comes on when the key is turned to On.) the other 3 were to plug for the transmission. I need this because I am going to put a switch in to manually lock the Torque Converter.

So the way I went about ripping these wires out, was actually not ripping anything out. I just took all the old wire loom and electrical tape off of every wire and started pulling the wires to the passenger side fender(where they go to the ECM). Then going inside the car, where the ECM used to be(under the dash on the passenger side) and pushing the 4 connectors out into the fender well. Then pull up from the engine bay to get them out, and piecing out what wires I still needed. I did not cut any wires or connectors off, except the ones I still need of course.

So now I have this wiring harness just laying on the ground, what a mess of wires. I think I'll hang it in the garage or something.

Oh, none of my headlight wires were in this harness either.
Just a few HVAC wires that I dont use any more either.