I'm in the process of reducing the engine wiring loom for my Subi EJ20 engine to the minimum needed to run the engine only.
I have identified and labelled the computer, engine, airflow meter, ignition igniter, oxygen sensor, throttle body and start plugs. Are there any others that I need to identify before doing any wire removal? Do I need to find the check engine light wires? Is there a diagnostics plug that I need to find?
I've removed all of the tape and things to make it possible to trace all of the wires. I have not cut any wires so far.
I'm assuming that this is similar to the pruning of a big old neglected fruit tree that's full of dead wood, water sprouts, root stock sprouts and inappropriate branches.
Am I right to next trace and remove all wires that are not traceable to any of the identified plugs as a first move? If so, what then? If not, then what?
I've never done this before, so I really need some help.
Hasten slowly.
Do you have a circuit diagram?
You may need to identify:-
ignition relay circuit
fuel pump relay circuit
Identify
Battery Voltage - always on
Battery voltage - via ignition relay
Battery voltage - via Fuel pump relay
Start switch circuit
Be careful about removing ground wires.
depending on year of engine......
things not in the engine harness:-
Crank angle sensor
Cam angle sensor
EGO
Knock sensor
Air flow sensor
Clutch switch,neutral switch, auto trans inhibitor switch
igniter
diagnostic plugs, select monitor(test connector)
oil pressure sensor
temperature sensor (may be one for ecu and one for gauge)
tacho output
speed sensor input
and possibly others I can't think of.
Best way is don't remove it until you know what it is.........:P
u2u me with questions
[ Edited on 9-7-06 by lexm ]
I spent an agonizing day mucking around with the loom, tracing wires back and forth and I could not bring myself to cut one of them. I was more afraid of cutting a wire that I should not cut, than I was concerned about cutting a wire that should be removed.
Today I spat tha dummy, boxed the loom up and posted it to Buggy Brad of Custom Off Road. It's not cheap, but at least someone who knows what they are doing will be sorting it out for me.
ah, psychedelic spaghetti fun!
Lettuce know if you need a hand installing it when you get it back.
Thanks for the offer Col. I may well need some help.
I look upon the fuel injected, electronically computer managed modern car engine as going against the tenets of Occam's Razor. That is that "The simplest solution is nearly always the correct answer". I am not convinced that electronically complicating car engines is an improvement over the older and simpler ways to run them. I consider it to be whizzbang jimcrackery.
I am also a Luddite, so that may explain my attitude.