S13 Chassis wiring problem (I think)

[GSXRJJordan]

So...
I drove my car to work today, and on the freeway, experienced the "hit a bump and lose power for a split second" jitters, and didnt think much of it. Later I took a left hander pretty hard and the car jittered then died. I thought I'd popped off my MAF wires or blew an IC coupling, so I coasted into a Shell station and popped the hood.

I checked everything (couplings, fuses, connectors), and it was all ok. Then I realized that with my key out of the ignition, the power to the car was still on. I checked my ignition switch (disconnected the connector), power was still on, so it's not a defective switch.

The only thing that powered off the car was pulling the 75A Ignition Switch fuse, or pulling the white power wire that goes to the fuse box from the clip on the battery terminal.

Then I realized the reason the car died on the street - although power to the car was on, the fuel pump was not. I tried to hot-wire the fuel pump (had some small female spade connectors in my toolbox), and couldn't remember which wires went where (I was incredibly frustrated by that point), so I plugged it all back up stock-like.

Luckily when I reconnected the battery, the fuel pump came on, and I got the car back home, but I still have the power problem.


I don't even know where to start looking for shorts. I guess I should look through the chassis harness from the fuse box to the fuse panel under the dash, but jesus that's a helluva job. Any insight would be great ~

[projectRDM]

Remove the driverside fender and start repairing the harness, then relocate it. You shredded something.

[GSXRJJordan]

^^^ Russ you're on my Xmas list :) I was actually going to PM you with a 'please take a look at my thread' message today if I hadn't heard from you.

I did the 'pull it up over the lip of the frame rail' trick back in the day, and I did a quick check yesterday - I'll look better today/repair any damage. Thanks =D

[GSXRJJordan]

Update: Took a look at the drivers-side wire situation: The tuck I did back in the day was still good; none of the loom was frayed/melted, and when I pulled all the tape/loom off, none of the wires stuck.

Further down that same wire group, I found a frayed section where a hose clamp on a hotpipe coupler had worn through the electrical tape. Only one wire's insulation was chewed through, so I cut that section out (about 1 1/2") and spliced in a new wire. Problem remains.

Any other chassis-gremlin-gurus out there?

[projectRDM]

Start pulling fuses, begin under the hood. When you pull the one that kills the problem, you've found the culprit circuit. Break out the FSM and begin tracing from there.

[GSXRJJordan]

The only fuse that did it was the 75A IGN fuse. The wiring diagram is nuts for that circuit. Damn.

[soreballz]

I have a similar sort of constant power issue that you have, only my car never shut off on its own. Mine doesn't happen after shutting off the car, though. If the car is off, and I put the key to the 'ACC' position to roll the windows up or play with the radio, then turn the key back to 'off', 95% of the time, power remains on.
It only goes away if I start the car or crank it over. If I leave it unchecked without starting/cranking the car, the fuel pump relay starts buzzing like crazy til I crank the motor over. I tried replacing the relay... Didn't help.

Don't you just hate electrical problems?

[sideview_180sx]

I say we fly russ out here to redo our harnesses.........

[GSXRJJordan]

update: I haven't finished working on it, but I've narrowed it down to the 25A Eng Ctrl fuse... I think I've got a bad wire on the ECCS relay. I'll check it out this weekend for sure.