While driving yesterday my engine simply quit. I towed the car home and I've probed all day yesterday and today. The symptoms that I'm experiencing are as follows


97 Legacy outback... converted to SOHC Phase 2. running 97 ecu MAF coil and harness rest is 99 RS stuff.

No check engine light in start position.
The ABS and Battery light (brake too if parking brake set) remain on when the key is removed and the temp guage is pegged at hot.
The fans both remain running and the ABS unit has a continuous buzz.
The lights stay on (if the stalk switch is on) and I can turn on the interior blower fan==also all while the key is removed.

The engine will crank over but will not start I've not yet checked for spark or fuel_I assume there is none as the ecu will not respond to my scan tool. My Equus generic obdII scan tool gives me a "ErrPr" code which has no reference in their manual.

If I remove the negative terminal to the battery the fans, lights, and the rest will turn off. As soon as I turn the key back on and off again I get the same results.

A couple of times the car has returned to normal with a steady idle and it revs normally the alternator charges at 14.3 volts-- a/c runs. Without warning something drops offline and the same probs return once in a few minutes and a couple of times in just a few seconds. Frustrating

I've attempted to isolate the problem by removing the ABS relays and unplugging the ABS unit. I've removed the ignition switch and it's harness to the four wire plug into the main harness only to find that when I jump the black white wire to the all black wire the same symptoms return. I have unplugged the alternator, changed to a known good one, changed the battery (because this ongoing crap killed the current one)... same problems returned with the new battery.

Fans unplugged-- tried that
IAC unplugged== tried that
relays removed..... all of them... tried that
no blown fuses... none at all

Green test plugs put together don't produce the test string


I'm at the end of my rope and it's got to be a simple fix.... Is my computer dead? what is it?

 

Interesting problem. It sounds like something is shorting and sending power to everything. I want to say that it's something in the ignition switch, but i'm sure you've jiggled that around. It's weird that the temp gauge is pegged, because that should be reading cold if the engine is. Have you tried contacting a dealer yet?

 

the main engine harness ground was loose. Not so loose that the car would never run but loose enough that when I tried to troubleshoot the problems I could not find the issue.

This morning I discovered that if I disconnect the coil, reconect it and attempt to start the car I could. Moments later the car would stutter, like the ignition was cutting out, the tach would zero out, and then either resume or then quit. When it would finally quit the same symptoms that I posted yesterday would then appear.

If I would pull upwards on the coil wires while it was running The engine would not quit, stutter, or otherwise react in any unfavorable manner-- I figured the problem was in that portion of the harness.

I removed the intake manifold and started sorting through the wiring harness. Unplugging and peeling the harness back, I discovered that the ground was loose. I continued to probe through the engine harness to find any shorts, bare wires, crimped wires, loose connections or shorts with a the continuity tester on my multi-meter. The coil wires didn't make any connection with ANY of the other wires-- according to the tests anyhow.

Doubtful that the problem would be resolved, I put the manifold back on and connected everything back up.

The car fired up the first time and has not had a problem since. I assume that when I was pulling upwards on the coil section of the harness I was tightening the ground making a more complete contact. I intend to loosen the ground again and try to reproduce the problem.

 

Sounds like you've done some very good troubleshooting, and I hope it's as simple as a loose ground. Subaru has been blamed for having poor grounds in the past, but that's exceptionally bad.

 

It's official.... loose grounds do very horible things to subaru cars.