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Which ECU wire harness kit should I get?

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Old Jun 23, 2021 | 05:55 PM
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Default Which ECU wire harness kit should I get?

When I get my new motor, I am also going to be replacing the wire harness from the ECU because, I might as well while the motor is out. Should I get a used F-Body one, or a new one from Painless Performance Products, Wiring Specialities, BP Automotive, Performance System Integration, etc...

The benefit of a used F-Body ECU wire harness is that all of the connections are already there, and the length is correct.

The benefit of a new one is that it is brand new and I can have it made with the LS7 injector connectors, but I would have to add pins/wires for any sensors not included, and I might end up having to coil up some excess wire length.

Inputs?
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Old Jun 23, 2021 | 09:12 PM
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F-Body one. Personally I would not even change the wire harness. There is literally no reason to.

Now having said that I WOULD go ahead and rewrap it with some threaded wrap instead of factory electrical tape. I would find all the wires that look crappy and resolder some new ones if needed. You are wasting money buying a new one tbh.
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Old Jun 23, 2021 | 10:50 PM
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Originally Posted by FCar2000TA
Should I get a used F-Body one,

The benefit of a used F-Body ECU wire harness is that all of the connections are already there, and the length is correct.

What logic is there to replace a used harness with a used harness? Am I missing part of the story?
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Old Jun 24, 2021 | 08:11 AM
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There is no logic.

I'd post a smiley face but for some reason it won't let me
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Old Jun 24, 2021 | 12:02 PM
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Originally Posted by LLLosingit
What logic is there to replace a used harness with a used harness? Am I missing part of the story?
This is my logic:
- The car has had some electrical oddities lately, mainly pertaining to the IAC valve.
- The current harness is in a 1999 TA that has been in the AZ heat for all 22 of its years. This tends to make wires brittle.
- I will already have the engine/trans out of the car, so this would be the best time to replace the entire wire harness.
- I will only purchase a used harness if the vendor has inspected it and replaced anything that needs to be replaced. I will not buy an as-is used harness.

Basically, I am already going to be in there, so this would be the time to do it.

I am leaning rather heavily toward the Wiring Specialities harness. The come with high temp wrap and can have LS7 injector and MAF connectors so I do not have to have adapters.
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Old Jun 24, 2021 | 01:49 PM
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- The car has had some electrical oddities lately, mainly pertaining to the IAC valve.
You are assuming it is the wiring harness. And what if it isn't the harness? Good job now you are out some money and back to square one.

- The current harness is in a 1999 TA that has been in the AZ heat for all 22 of its years. This tends to make wires brittle.
While I can understand this I would still say inspect your own harness, rewrap it, and then just run it. If you find wires that are looking like they may be no good you can solder new ones in.
- I will already have the engine/trans out of the car, so this would be the best time to replace the entire wire harness.
Probably the only logical response, but it is almost like saying "I have my wheels off while doing a rotation I might as well go ahead and replace the hub."
- I will only purchase a used harness if the vendor has inspected it and replaced anything that needs to be replaced. I will not buy an as-is used harness.
This is the worst one yet. You are going to go off a vendor, who mind you you don't know and are placing all your faith in, to say that everything is all good. That is not at all smart.


I'm telling you man you would save a lot of money and effort just rebuilding the harness you have and doing it yourself. If you wanna burn some money then be my guest but I'm going to try and steer you away from that lol

Last edited by shakenfake; Jun 24, 2021 at 02:50 PM.
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Old Jun 24, 2021 | 02:37 PM
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You are assuming it is the wiring harness. And what if it isn't the harness? Good job now you are out some money and back to square one.
- The current harness is in a 1999 TA that has been in the AZ heat for all 22 of its years. This tends to make wires brittle.
While I can understand this I would still say inspect your own harness, rewrap it, and then just run it. If you find wires that are looking like they may be no good you can solder new ones in.
- I will already have the engine/trans out of the car, so this would be the best time to replace the entire wire harness.
Probably the only logical response, but it is almost like saying "I have my wheels off while doing a rotation I might as well go ahead and replace the hub."
- I will only purchase a used harness if the vendor has inspected it and replaced anything that needs to be replaced. I will not buy an as-is used harness.
This is the worst one yet. You are going to go off a vendor, who mind you you don't know and are placing all your faith in, to say that everything is all good. That is not at all smart.

I'm telling you man you would save a lot of money and effort just rebuilding the harness you have and doing it yourself. If you wanna burn some money then be my guest but I'm going to try and steer you away from that lol
I will wait until the engine is out, and see what the wire harness looks like. Maybe I could just redo the wires/pins/connector for the IAC valve.

Last edited by WhiteBird00; Jun 27, 2021 at 08:15 PM. Reason: Fix quoted sections
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Old Jun 24, 2021 | 02:49 PM
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Yea that is what I would do

Also my nicely laid out message didn't save the quotes fml

fixed it
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Old Jun 25, 2021 | 01:07 PM
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Is there a how-to somewhere for removing the ECU wire harness? Can it be done without cutting wires?
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Old Jun 25, 2021 | 01:13 PM
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It should just be held in by clips and should not require cutting. I would start by tracing all the wires down and start undoing their frame connections
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