2000 engine compartment wiring harness

The common damage is above the cylinder 5+6 area, I've heard a lot a similar comments!

Glad to see someone else out there who still knows what a nailboard is and how to do proper harness work.

BTW... I am seeing more and more issues w/ people having broken and shorted wires in the area of cyls 5 and 6 and from there to the firewall as well. Common issues include basically any electrical fault code (stuck high, stuck low, intermittent, lack of function, etc) on anything that runs off that harness:
- injectors
- MAP (on 96+)
- upstream O2(s)
- IAT
- CTS
- TPS
- IACV
- CPS

off the top of my head. Probably others. It's due to the harness flexing every time the motor moves or vibrates, since it jumps from the firewall to the top of the head right there. It most commonly affects injector drive circuits and TPS from what I've seen but can affect any of the listed items. Typically I have people report they are getting a misfire on a cylinder or two, or a circuit failure code, and have already tried replacing the component. When they dig into the harness they find wires broken, chafed, and/or partially broken.

I recommend that people use quality sealant lined heatshrink butt splices (marine grade is great) and splice in a foot or two of replacement wire of the same gauge. Ideally, use the high strand, high temp silicone wire typically used by RC car enthusiasts, it's far more resistant to metal fatigue than the factory wire is.

Out of my 3 harness's, NONE had any degradation anywhere else. All of the damage on all 3 is in the fuel rail section, nothing on the firewall, the starter/oil/dist, coil pack, or the rear trans sensors. All the damage is in the rear half so cumulative heating by the wires is not out of the question, but I have to believe it's mostly exhaust heat.

Kastein......from the start of this thread I wanted to build a new "bulletproof" wiring harness! I found that sourcing all the connectors/terminals to "almost" impossible to find!

It's Alive !!

Finished the harness Sunday and got it on the road. I took it to emissions early today and everything passed but the CEL. Got home and took the cluster out and sure enough it was a blown bulb. I took it back this evening and it passed so tomorrow I'll go get my title and registration done!

In post #39 (last pic), that is high-heat fiberglass tape. And in post #44 the pic shows high heat reflective split loom over the regular split loom for more heat separation in that area.

In post 39 it sure looks like someone pulled all the locking tabs out of your injector connectors too -- how do you get them to lock on the injector?

All them were brittle and broke. I have tried to find the lock tabs but with no success. So far they haven't fallen off in a couple thou miles.

IMO those tabs on the injectors are not necessary. I broke a couple of mine when I did the 4 hole injector upgrade and they stay secure. Of course my '00 is just a DD so it is not like I am bouncing around out there. You have to realize a lot of things, like those locking tabs, are for manufacturing. So things don't get pulled accidentally when other things around them are getting installed as the car goes down the line.

Did you use only the factory wires when you made the new harness? If not, what kind and gauge wires did you for the repaired portions of the harness?

I have an intermittent misfire fault that seems to only happen when the engine bay’s hot and there’s little to no airflow through it to keep things cool.

ZomBrady said:

Did you use only the factory wires when you made the new harness? If not, what kind and gauge wires did you for the repaired portions of the harness?

I have an intermittent misfire fault that seems to only happen when the engine bay’s hot and there’s little to no airflow through it to keep things cool.

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I only used the factory wiring from 3 different harnesses to make one good one!

RCP Phx said:

I only used the factory wiring from 3 different harnesses to make one good one!

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Understood. I was kinda hoping for different answer. Simply to save on the hassles of getting good donor harness.

As long as you have a good wiring diagram you could easily make a harness from scratch. Be aware that there are some "twisted-pair" for items like the O2 sensors.