Weird problem

[Twizted_3KGT]

Vehicle: '88 Formula 350, 135k

Background: Car is my back-up car/winter beater. It sits during these snow-free months, and gets taken out for the snow-filled ones. I've replaced almost everything to do with ignition, from starter to ignition switch in recent years. I'll usually start it up once a week, let it run, and shut it down.

Problem: About a month ago, I started it up, held idle (due to MAF unplugged for seperate problem) 'till closed loop, then let it idle for 20 minutes on it's own. Hopped in to take it for a quick drive to see how everything is on it. As soon as I hit the brake pedal the temp and volt gauges shot to their peak and the engine stumbled to a stall. I turn off and remove the key, I can see the 'Service Engine Soon' light dimly illuminated in the dash. I wiggle the battery wires, and the wires going into the firewall, the 'SES' light disappears, I start it back up, runs just fine. Again I hit the pedal, again the same result, stalls out. This time wiggling wires doesn't make the light go out. I say screw it, and it of course drained the battery by the next week, and I haven't looked at it yet.

Looking for: Just some ideas as to what it might be, also hoping someone might have had the same experience. Obviously it's a short to power somewhere. Could it be an PCM problem?

[Morley]

Doubt it is ECM related unless the short has fried it.
There is a very large connector on the driver side on the firewall that has most of your wiring going to it. In the center of that connector is a screw with a 10mm head, that screw holds the connector on. Make sure the connector isn't loose. If it is tight, try taking it apart and see if any of the pins in there are corroded. There are also 2 large wire bundles that go behind the engine, make sure they aren't pinched by the engine and haven't been worn through. And look up under the dash near the brake pedal for any bare/worn wires. Also check all of the fuses.

[Twizted_3KGT]

Originally Posted by Morley

Doubt it is ECM related unless the short has fried it.
There is a very large connector on the driver side on the firewall that has most of your wiring going to it. In the center of that connector is a screw with a 10mm head, that screw holds the connector on. Make sure the connector isn't loose. If it is tight, try taking it apart and see if any of the pins in there are corroded. There are also 2 large wire bundles that go behind the engine, make sure they aren't pinched by the engine and haven't been worn through. And look up under the dash near the brake pedal for any bare/worn wires. Also check all of the fuses.

Just the kind of answer I was looking for Specific places to look, thanks! I'll check those out next week and update.