I am putting TPI in a car that has a carb setup. The motor has a Wiring Harness hooked to it now. I know that I have to get a harness for the TPI. My question is I am supposed to use the harness that is already hooked to the motor with the one for TPI.

 

The carb engine harness is of no use to you on the TPI. If you use say an 87 carb to an 87 TPI, all you would have to do is disconect the bulk head connector on the drivers side firewall and attach that part of the TPI harness. When you are trying to match up harnesses from different years, you may have to move a few wires here and there. Of course you need the harness/ECM on the passenger side.

 

So the wire harness that comes from the driverside I can disconnect that whole thing, but the harness that comes from the passenger side keep that one. It worried me because the harness from the passenger side plugged up to my alternator but the alternator still has a hot wire the goes to the battery. So if that harness is connected to anything I need to plug into for the TPI should I just disconnect it and tuck it away.

 

Your harness that connects to your drivers side of the car is for your headlights, gauge cluster, and interior lighting and interior power. The harness that goes to the passenger side is for the ecm. You will want to get a pin out for your ecm that you have. Once you have the pin out for that ecm, all you have to do is repin it for your tpi ecm. I can get you both diagrams if you can not find them.

 

If your car was a carbed V8 Monte to start with, the original computer harness is useless. You will need to make the hole in the firewall a bit larger and pass the harness through there. You'll also need to add 4 fuses (injector 1, injector 2, fuelpump/fan, and crank fuse), and then splice the 15-pin connector into the Monte dash harness. TPI's work well in Montes.

 

No, it is not useless. If you know how to repin, add a few wires and change connectors, it can work fine. But if you want to go spend $100 on a used harness when for like $15 more you can build one that will work fine, go ahead.

 

Add a few wires? You're a better electrician than I am, then.The CCC computer is not even the same kind of ECM. The carb ECM has a TPS, VSS, Mixture Control Solenoid, Coolant Temp Sensor, and O2 sensor, plus the emissions (EGR and AIR stuff) and a MAP. That's it. There's no way to power the fans, or injectors, no IAT, and a bunch of other things I'm forgetting on a TPI car.

Now, if you were saying that he could re-pin a TBI harness to run a TPI, that's possible.

 

Yes they do!
I had two harneses to deal with and finally just mapped it all out and made a new one from scratch. Was the best thing I could have done because now I've had over two years of absolute trouble free wiring. Everything is soldered (especially at the ECM connectors) I can also remove the entire TPI without fighting the harness because I made it fit the way I wanted it to.
Use any harness you have just for the wires and begin.
That's the best route IMO.

 

Its actually the other way on the Montes (at least on my 86')
The alternator actually comes from the drivers side and is budled with the stuff on the pass side. The harness from the ECM comes up from the passenger side with the A/C stuff and EST setup.
Be careful what you cut!
If you are doing a MAP setup then you'll want to leave the existing power wires from the drivers side for the charging and starter alone for the most part. Everything for the new engine control harness will come from the passenger side with a few new connection sets running into the firewall somewhere for the fuel pump, injectors, TPS, IAC.
Separate everything and plan it out before you remove too much.

EDIT: A video camera and a pad of paper is INVALUABLE when removing everything. Do it slowly and record where it all came from so you can review it later if you have questions.

 

Yeah I began to take my motor apart lastnite to pull it. I am starting to get a better feel of were the wires are coming from. I think I will keep the wires that I need and tuck the rest just in case I will ever need them again.

 

Exactly!!!! I do that and have saved hundreds of $ in harnessess. It really is not hard. Look on the classifieds or e-bay for used wiring harnessess. Use them for wires and connectors. Get a diagram and get started.