Wiring Harness Simplification Quetsions
 

Howdy,



My car will be down for 3-4 weeks while I wait for my turbo kit to get fabbed up and shipped to me. I figured I would take advantage of this time and clean up the engine bay.

Since I am going single and eliminating the emissions equipment / solenoids, I wanted to eliminate the wiring that accompanys them as well.

Do I need resistors of any type when cutting out wiring or can I just cut them out? For instance, all of different colored connectors that run to the emissions solenoids under the UIM. Can I just cut these off where they meet up with the main wiring harness and wrap it with electrical tape?

The only solenoid I need to keep on that rack is the orange solenoid closest to the firewall correct?

I no longer have an air pump and I would like to clip that wire as well, the EGR, all of those parts have wires dangling around that I would like to eliminate as well. I tried doing a search for "wiring harness simplification" "simplifying wiring harness" etc.. and could not find any information on this topic.

Thanks

I am running a PFC

I can't help you with the technical stuff on what to cut, but when I did my harness on my Skyline I was told to individually heat shrink the ends closed on every wire you cut. Lasts longer than tape, keeps water out and makes sure no signals get crossed.

If you do it right you can have a clean setup. Unwrap it all, pop up the little tabs on the connectors, tug out unwanted wires, and re-wrap.

I will do that when I end up dropping a new engine but for now I just want to eliminate clutter as a temporary fix. I will be okay cutting wires and shrink wrapping them then?

Very important...don't go just cutting off the unwanted connectors first. Unwrap the the whole thing and study how a lot of these connectors share the same wires such as ground. I did this last summer and there are many areas that connect together that you need to be careful about.

Also, have a wiring schematic handy if you get lost or need to replace some wires. Mine was especially tough because all the wires turned brown where they were exposed to years of cooking under the UIM...so I had to trace them all the way back to get the colors right. The tough part was when they just broke on their own and I had to really figure what went where...nightmare.

The only solenoid I kept was the purge control with my single turbo. So much simpler.

To be more specific... regarding the multicolored solenoids on the rats nest in this picture. These are the ones I want to eliminate as they really clutter the UIM area and I would prefer them gone.

Can I clip these and shrink wrap them?

I can remove all of these solenoids when going single and upgrading my FPR correct?

Also, I finally found my vac leak, it was the nipple on the LIM that points towards the firewall.

I wouldn't cut them all the exact same length. Maybe stagger the cuts and then wrap individually. Consider putting fusion tape over the shrink wrap.

Yes.



Some links of what others have done:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/single-turbo-fd-harness-mod-pictures-768657/
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/electron-manipulation-336924/

You can really clean the engine ( EM) harness up a LOT if you know what you are doing. And yes the PFC does not need resistors, the original ecm would. What you have to do is 1) understand completely what each wire does, where it goes and how the PFC can do without it and 2) work with the shop manual electrical section. I have personally done 4 engine wiring harnesses. Actually I have done the entire wiring harnesses on 4 cars. There is 4 major harnesses - Engine, ring, dash and rear. The Ring is the hardest, followed by the dash, then the engine and the rear. On my FDs I have stripped out EVERY single wire that does not serve a function, and that's a shitpot load of wires. I run no ABS, AC, Emissions, Wipers, Pwr str, etc etc.

The engine harness needs to come compeltely out of the car and into the garage. There is it broken down to bare wires. A LOT of work will take place to get it to this phase WITHOUT cutting into the wiring insulation ( you do not want to comprimise the insulation with a knife edge ). The each single wire that does not serve a purpose is stripped back to the ECU/X-?? connectors is lifted out, NOT pulled out.

After I am done there is something like 17 wires left in the harness that serve a purpose. I add several more spares for electical gauges and such. Then it is carefully retapped and Wire loomed up. I use the Summit racing wire loom in Red. Looks real snappy !

Below is the latest one I've done.



Later

Very impressive, this will definatley be added to my "to do" list for the winter makeover which is already getting to be a bit much.

-Single Turbo Conversion...in progress
-Sleepy Eye, HID Projectors w/ custom housings.
-Relocating PLX DM-5 Wideband Gauge to replace OEM Oil Pressure Sender
-Replacing all rear bushings & Suspension Components
-Relocate Battery to Rear Bin
-Install Water Injection
-Install FJO Injector Driver
-Install Meth Injection
-Upgrade water pump or go electric
-Wiring Harness Removal and Simplification

In my opinion, just cutting the connectors and wrapping them is not ideal. Do it once and do it right.

I did exactly what badddrx-7 did...truley simplify the wiring harness all the way to the ECU. And when you tackle that job, you can also take advantage of running alot of the other wires through the engine wiring firewall grommet like the FJO harness and your meth/water injection harness. Much cleaner and simpler in the bay.

Can this wire be eliminated since I am going single? I have it circled in red

Sorry, for the vague question. "This wire" is referring to the turbo control solenoid valve... Everything else is good on my wiring harness except for this mystery wire. Can't remember where it ran to --- I feel like it is / was part of the rats nest but is the hidden solenoid. I have been using the attached pitcher as my reference.

No where on this diagram do I see a tag for the turbo control solenoid valve which makes me wonder if it is the "hidden" solenoid in the picture?