Wiring Harness of JDM engine too short

[Victor Charlie]

I'm putting a rebuilt JDM 7m-gte, probably 1990 or later, into a 1989 supra with manual trans and 7m-ge engine.

Got the car all built and then the last step: harness doesn't make it to the glove box location of the ECU. Is this because it was from a LHD car? I have an extra harness from an NA engine. What's the best solution:

1) extend the harness by cutting one wire at a time and soldering it to corresponding wire from the NA connector.

2) get the right harness and replace

3) another solution.

I'm sure this has been discussed many times, but I'm having trouble finding the right thread.

 

[JDMMA70]

use a USDM harness.

 

[Victor Charlie]

use a USDM harness.

Just to double check:
the engine is in the car and ready to start. How much will I have to take apart to rewire? I wired it on the stand, and I haven't tried changing a harness on the car. also, what can I expect to pay for a USDM harness?
thanks.

 

[lewis15498]

Just to double check:
the engine is in the car and ready to start. How much will I have to take apart to rewire? I wired it on the stand, and I haven't tried changing a harness on the car. also, what can I expect to pay for a USDM harness?
thanks.

You would have to cut every single wire, put in an extension, and solder it back together. Do it one at a time to reduce the chance of making a mistake, but it would be much easier to just go buy a usdm harness. New harnesses are pricy, I think driftmotion sells them but there like $600 iirc. Post an ad in the WTB section and im sure someone has an extra theyre willing to part with.

 

[shaeff]

Expect to pay around $100 for a decent harness. If it's in very good shape, you'll pay more. I've seen them go as cheap as $50-$75 though, so maybe you'll get lucky.

Wiring up the harness on the car isn't too bad. I did it on my car in late December once. It wasn't fun, but it's definitely possible. Worst case scenario, you'll have to remove the 3000 pipe and throttlebody to give yourself some extra working room, but I didn't have to remove much of anything if I recall correctly. Just be careful, and pay very close attention to where/how the harness is supposed to be routed.

 

[Victor Charlie]

Expect to pay around $100 for a decent harness. If it's in very good shape, you'll pay more. I've seen them go as cheap as $50-$75 though, so maybe you'll get lucky.

Wiring up the harness on the car isn't too bad. I did it on my car in late December once. It wasn't fun, but it's definitely possible. Worst case scenario, you'll have to remove the 3000 pipe and throttlebody to give yourself some extra working room, but I didn't have to remove much of anything if I recall correctly. Just be careful, and pay very close attention to where/how the harness is supposed to be routed.

Thanks, that's just what I was looking for. I have a parts car to go by, but it is still running and I can't bring myself to slay the beast for a wiring harness.

 

[shaeff]

Also make sure you get a wiring harness that matches the year of your chassis. Considering you have an '89 (which is sortof a Frankenstein year), you should specifically look for a harness from as close to your build date as possible.

 

[Victor Charlie]

Also make sure you get a wiring harness that matches the year of your chassis. Considering you have an '89 (which is sortof a Frankenstein year), you should specifically look for a harness from as close to your build date as possible.

For the benefit of anyone else in this situation:

You were right. I pulled the old harness. It was easier than soldering, but a bit of a mess. I pulled the throttle body, the 3000 tube, the fuel line to the cold start injector, the ISC valve, the accordian air duct (for the oil pressure sensor wire), and that made it easier. I don't know how anyone could do it with the throttle body on.

I'm confused about the wiring differences for the '89. I thought I saw somewhere that the 89 body wiring was standardized so every model had the same wires, but engine wiring is obviously not standard. The EPC lists about 5 different harnesses for 89 LHD turbo supras. I think I will look for an ECU with a harness.