Splitting/Rerouting wire harness

[satx88supra]

I'm trying to get my 88car turbo back on the road. It has been running but i took the pludge to paint the car and engine bay. Well after i had the engine out the wires on the hot side and across thevalve cover are just plain toast. Brittle, cracked insulation, plugs cracked, etc!!! So here's my question/plan.......Is it possible (im sure it is) to split the harness to go two routes? I'm planning on drilling a hole in the same area some have done for the JZ swaps. Trace all wires back to the main ecu plug, unpin them, separate from harness, repin. That way i should have all hot side wires in one wire bundle and cold side in theres. Next i want to use the OG hole for the hot side then route it under the ABS, out the fender wall, mounting to the wheel well, and back into tge engine bay by where the ic pipes is. So that's the plan and i need to here any concerns. For example...Can anyone tell me if i would have an issue lenghting the wire from the cold start injector and water temp sensor?

 

[satx88supra]

No one!
I guess i'll just proceed. I'll post pics when its done.

 

[GC89]

IIRC others have routed the entire harness under the dash and out the driver side so I think you will be ok on length there. The hot side sensors (cps, o2, temp sensors, ac switch, oil) all should be plenty long to rout through the render well.

The only issues I can see is that quite a few wires in the harness are spliced together (mostly ground and + 12v) If there is a wire from the hot side and cold side spliced you would have to rerun at least one side of the wire and splice back near the ECU plugs. Also if you wires are baked you should rerun a new wire all the way from the censor to the ecu. ECU pins as well as the sumoto style for cps, ect are no problem. I have not found O2 sensor and oil sending unit terminals anywhere yet. From your picture your pre 89 so the ecu temp sensor and cold start switch plugs are the old style and I have yet to figure out how to de-pin those or find pins. I would talk to Dr. Tweak he may be able to get some of these. The best route if you cant replace the entire wire is to slice using uninsulated butt connectors and heat shrink also slice a ways back into the harness for better strain relief.

Your going to need a good set of crimpers and a lot of time. I just finished up wrapping my rebuilt harness last night and wish I would have seen this earlier, I could have checked for any splices that may cause issues for you. I have easily 20+ hours into my harness at this point, so good luck and be sure and post pics when you are done!

hope some of that helps.

 

[satx88supra]

Thanks. I just ripped all the harness tape off last night and labeled/ moved what i xould. You are correct in some wires having common ground splices. Im sure i can cut these and move them closer to the ecu plugs. I am going to change the baked wires out. I have a donor harness my bro n law had for his jz build. So i can keep most of the wire coloring and such. 20hrs......thats some work and looking at my harness i can believe it. Hopefully i can have some pics up by the end of the week. Will let you know.

 

[3p141592654]

Devil's advocate. The stock routing is good for at least 20 years using pvc wire. If you are concerned that another 20 years will not be enough, then use a teflon based wire for the part that goes over to the hot side of the engine. Since you cannot do anything about the connector locations, they are going to be brittle no matter what route you use, so your new scheme won't make any difference connector wise.

 

[satx88supra]

I agree connector wise. I'm mostly trying to get the wires that cross the covers to go away. Have an idea after that for a custom cover with the is300 COP conversion. So no devils advocate my friend....thank for the insight on the connection points.