7mgte Wiring harness question
 

Is there anyway to swap out my 87 ecu and harness with an ecu and wiring harness from a 91? The car is an 87.

Um.... why? There's no significant difference in power and the redline will be lower.

The dash harness is different too so that will need to be altered or replaced as well. CPS uses a different connector so you'll either need a '89+ CPS or you'll need to modify yours. I don't think there are any other big surprises.

The only harness I have found in 3 months is a 91 and wanted to see if it was possible. The 89+ cps connectors would have which color plugs? yellow or grey or whatever color they make them?

I believe the plug on the 89+ harness is just black. There is no pigtail on the CPS side, the connector is built into the CPS housing. You could cut the end off of the '91 harness and wire in the end from the '87 harness.

Is there a reason your harness can't be rebuilt? Toyota does still sell many of the replacement connectors for it. It is a lot of work, but I don't know how bad it is... It may end up being just as much work to convert and swap a later model harness.

I did not know Toyota sold replacement connectors. Thanks. We are going to try to rebuild the old one.

Check on availability of any that are significantly damaged. Some are discontinued. Some you will find are compatible with other vehicles even though they are not list as such... For example I believe the '89+ N/A ECU connectors are compatible with earlier years, just the color is different.

I have a mechanic working on my harness because I have no idea how to work with it. I want him to rebuild my old harness and he said he will-however he wants me to try and find another harness first. So just so I know-will an 88 harness work with my 87 ecu? I'm thinking getting another harness won't be that much better because it might not be in much better condition.

Does anybody know of a shop that can rebuild wiring harnesses? For an 87' mk3 with a 7mgte..

What would have to be done to switch the manual harness to auto? I know its easier to just get a replacement manual harness but I cant find one. So is it worth it to try the auto?

Which are you asking for: adapting a manual harness to an auto or adapting an auto harness to manual? An auto harness should work in a manual equipped MKIII with no problem, as-is... The same is not true for the opposite configuration.

Okay, so I have an auto harness I want to put in my manual supra.

You will need to place a jumper between 2 connectors to bypass the neutral start switch (that isn't present). And if you want your reverse lights to work, you have to create a jumper for them as well. Other than that, the harness is plug and play

To clarify on your statement btwilson86, if this is not done (jumping the 2 connectors to bypass the neutral switch), will it hinder the car from starting at all? We put an 88 auto turbo harness in my 87 manual and its not wanting to crank at all.

Correct. This will cut power to the starter solenoid, so the starter motor won't crank.

I believe I may have mistyped my previous post, there should be a round connector with 3 terminals heading down towards the transmission; the jumper connects 2 of those terminals to complete the circuit. The reverse light switch connects to 2 different connectors. I'll see if I can find the connector and pins in the tewd for you

To complete the starting circuit, you will need to place the jumper between terminals 2 and 3 in connector D at the top of the image

http://www.cygnusx1.net/Media/Supra/...n/Main_039.gif

For the reverse lights, you will use connectors A, B, and C (B is the same connector as above). You should have A and B on the new wiring harness, connector C is on your transmission. You will want to run 2 wires, one from connector A pin 5 to connector C pin 1, and the other wire from connector B pin 1 to connector C pin 2. It actually doesn't matter which wire goes to which pin on the transmission connector (C) as its just a open/close switch.

Hopefully all that makes sense lol


http://www.cygnusx1.net/Media/Supra/...n/Main_078.gif

:bigthumb:Thank you! This info goes a long way, and of course, you might not see the end result of your effort, just keep in mind I'm doing an extra dounut and burnout just for you. Keep up the good work guys. :bow: