Engine Harness Questions

[Turbo Habanero]

I am currently putting my 7mgte with r154 out of my 87 into my 89 (auto) Shell i was told to keep the harness from the 89 and it will work fine just got to bypass N.S switch

But im afraid i have to replace the harness in the 89 now does the harness have to be from a TEMS and Auto car ?

Any advice and tips are very welcome.

 

[89supracrazy]

If the harness from the 89 is grey plugs it will not plug up to the 87 ecu. It goes like this, 87 to 89- yellow plugs and 89+ to 92 is grey plugs. The tems I am not familiar with but it has to something with the suspension. I do not have that on my car.

 

[reincaster]

Just get a harness that is the same year as the body of the car, and the same model.

Be aware that there are a few sensors you will have to change on the water neck. The transmission wings also needed a bit of trimming to fit the bigger 89+ mounts. I just used the leftover 89+ wings from the precious owner of my car.

 

[Turbo Habanero]

Ok so I know I need to match the yellow\grey plug together I am also using the 89 ecu with the 89 harness but I am replacing the harness on the 89 my question is since the car is a auto and also has tems is the harness I am looking for have to come from a auto\tems car? Or are they universal beside grey\yellow plug

 

[Turbo Habanero]

Someone out there has to know the awnser to my question lol

 

[bombinuass]

so let me get this straight.... you have an 87 5 speed. your pulling the motor and tranny and putting it into an 89 body? or just swaping motors? if your going from manual to auto then just use the auto ecu and the 89+ harness. i have a 87 auto ecu with my 5 speed. you may have to change a few connectors.

 

[Turbo Habanero]

Yes. But I need to replace the harness. I need to know when looking for a harness does it have to be specific to the car other then just it be 89+ harness.

 

[Suprafied]

I am in the same situation bro!! I have a 89+ 7mgte in my 86.5 model car. I cannot figure out which harness and ecu I need.

Frustrating when your sorta new to these cars.....

 

[suprajim54]

IIRC, the first thing is to be sure the ecu and harness match up as far as yellow plug (early 89 and earlier models) or grey plug (89+). I'm pretty sure the body harness plugs are different between yellow/grey plug so its best to match the ecu and harness with the year of the shell. You cannot use a manual harness on an auto, but you can use an auto harness on a manual. If you do, you will need to do some wiring with the reverse lights (they won't work) and jump the neutral safety switch. Also, if you use a grey plug ecu/harness combination on a pre 89 engine (or vice versa), some of the sensors may need to be swapped as the 89+ plugs are different. Someone else may be able to provide more info about which ones are different. Of course, the ecu needs to match the transmission you have. The TEMS will not matter as that is on a separate harness.

So, Turbo Habanero, based on your initial post, you will need a 89+ manual ecu and 89+ (manual or auto) harness and will need to change some of the sensors on your 87 motor to 89+. If you have to buy one anyway, it would obviously be easier to get a 89+ manual harness, so you don't have to do the wiring mentioned above.

Suprafied, you need to get a yellow plug (pre 89) harness and ecu and swap some sensors from the 89+ motor to be pre 89. Maybe you can work something out with Turbo Habanero to swap. Lol.

 

[Scruggs86.5T]

The TEMS wont matter, dont worry about that part. Just make sure you mate up yellow harness to yellow ecu since your harness is yellow plug. I know if you want to you can use a yellow plug ecu and put it in a grey plug car. There is a way to transfer the pins from the engine harness to the body harness. I dont know where this info is though. The rest is the change from manual to auto which I know nothing about. Good luck.

 

[manzai]

I just swapped an 88 Turbo motor into my 89 N/A. I did the swap and wiring myself.

1. Understanding that there are 3 styles, not 2, of ecu harness combo is paramount. 88.5 and prior. 89. and 90+.

2. Everything about an 89 gray plug harness is the same as an 88 EXCEPT the plugs themselves. The pinout on the 89 ecu plugs is even the same, just the connector itself is different. 90+ is a different story.

3. 88 Engine sensors will be fine with an 89 harness. Not a 90+. 89 is mostly 88, but with different connectors.


If I read your post correctly it sounds like your 89 auto harness, although it would work perfectly for your goals, MUST BE REPLACED for some reason, right?
Otherwise, you could use your 89 turbo, auto harness with no problem at all. I used a 92 auto harness and ECU for my swap. The only tricky part is getting reverse lights to work after. Auto harnesses and ECU's are fine for manual cars, the opposite is not true. I hope this helps.

Andrew

 

[Turbo Habanero]

If I read your post correctly it sounds like your 89 auto harness, although it would work perfectly for your goals, MUST BE REPLACED for some reason, right?

Yes. Its abit beat up reason for replacing. My question would it be better to look for a manual harness for a 89 and if I do will the harness work with the 89 auto ecu or should I just look for another auto harness or is there any difference.