What to do about wiring?

[mpowerful]

So im starting this project track e30. Ive got it mostly stripped and now im turning to gwtting the ineterior trimmed out the way i want it. My question is what do you guys do about wiring. This car is basically going to be a tt car. Im not concerned about keeping most of thw street comforts. This leaves me with a dilemma. Now i have a crapton of exceas wiring and much of it terminates to nothing. The simple thing would be to ignore it and pull fuses. I guess my question is do i take a mild approach and just do that or a wild approach and rewire? Retain fusebox? Any combination of the above? Car will be running a refreshed m20 while i build a 24v for it and both will be running stock harnesses.

Oh its an 88is.

[TobyB]

Having had a car with totally butchered wiring,
my version was to strip all the extra harnesses
(window, stereo) and then just retain the stock
harness intact. That way, at least, I can use the ETK
to figure out what does what. There is some wiring in the
main harness you won't need- but the 2 lbs you save will
cost you hours and hours to strip out.

Whut I did.

t

[jlevie]

There are some obvious things that you can remove the associated wiring. Like the windows, audio system, and check panel. Best to retain the wiring/switches for the mirrors so you can adjust them and retain at least enough of the HVAC system to have a working defroster. You also want to retain the wiring for the wipers.

Be very careful when removing wiring and make darned sure that you aren't removing more than you should. Check, then recheck before pulling any wiring. I think I spent about two days pulling unnecessary wiring from my last Spec E30 and rerouting the wiring that ran across the car under the floor mat for the passenger side mirror.

[mpowerful]

Thanks for the advice guys. Looks like i will take this route. Pull the unnecessaries and keep only what i need.

[mpowerful]

What i found in my car is that the wiring harnesses are beautifully modular! I pulled the cruise wiring, stereo wiring, hvac harness, , and door/floor harness. With the exception of the door harness the rest simply plug in under the dash. On the door harness i had to cut and terminate four wires that came out of the main underdash loom and went into the drivers door. All in all took me about 20-30 mins to eliminate 75% of the cars in cabin wiring.

[mpowerful]

For the record the onlywiring left inside is main underdash loom, harness for the exterior lights going to rear, fuel pump wiring, cluster wiring, and abs stuff.

[djjerme]

Mine was butchered to begin with, so I had to do some surgery anyways.

Not to mention, it's now 30 year old wiring (my car started out as an 85.)

So, while I originally just thinned the harness and made it usable, I did end up removing the stock gauge cluster and the check panel and using aftermarket gauges. This winter, the plan is to completely remove the entire chassis harness, and rebuild it from either scratch or use an after market (like Painless or Ron Francis..)

Then I will only have the OEM engine to ECU harness to live with.

[mpowerful]

^in the future i may do this out of intellectual curiosity and simplification.

[djjerme]

If I wasn't bound by rules for the series, I would replace the whole thing and go aftermarket.

[TobyB]

Body harness is free, you know. It's the engine harness that's locked down.

I agree- 80% of the wires in the main body harness are useful. I even reused the ABS
sensor wiring, brake warning, etc, for diff temp and stuff like that. Tearing into that harness is only
rewarding in that it's fun, and you can make sure there's nothing ugly in there.

It really only saves a pound or so.

t

[djjerme]

^^ Yeah, I am aware of the wiring rules, and was also talking about the engine harness.. Got bit by the main Fuel rail connector in the past.

The main reason I am going to rip and redo is simplicity and reliability - which the current rats nest doesn't fill me with (take a look under my dash next time you see my car.)

Trust me, I am a "Go with stock whenever in doubt" kind of guy, but like with my own home, you have years of undocumented, previous owner repair work and additions to deal with, it's sometimes better to just set fire to the damn thing and push it out in to the street.

(doesn't work so well with the house - unless you live in a trailer park.)

[TobyB]

hee hee- you could do it, though, with the E30 in the garage,
and be R3v thread of the week, if you misspelled enough
poping of the tairs...

Yeah, Bob's car, which was really a very nice race car, had that problem- any wiring
hiccup took twice as long to diagnose because shit ran everywhere.
My green 2002's that way, too- the stock harness is in there and still partly hot,
except for all the added stuff, and stuff that failed and was bypassed on a race weekend...
Hell, the transponder's STILL wired to the switched side of the accusump!

But when you start digging in to all the TIME it takes to redo, document, and then test
and debug, it turns into weeks and real dollars. I was always surprised that almost every
thing I 'cleaned up' on that car took testing and debugging- things as simple as a better
alternator bracket would go south...

t

[Emre]

If it's a pure racecar, then you really don't need much in terms of wiring at all.

For my vintage racer, I'm going to be installing a complete kit from Painless. It includes wiring harness (chassis and engine bay), fuse block, and switch panel. Do it once; do it right.