Warp Core Breach Eminent...

[BumbleBrick]

...Or at least that's what my temperature gauge has been saying.

It started a couple weeks ago when I was on my way back from a friend's house. I was on a pretty fast section of road, music blasting, flying through the chilly winter night when I saw the needle on the temperature gauge was ALL the way up, actually <i>past</i> the "oh s#!t orange" zone. I pulled over to the shoulder and coasted to a stop with my hazards on and the heat blasting. The needle receded, and stayed at its usual 9 o'clock position all the way home.

There was no smoke, no fire, nothing. I checked the coolant level and found it to be normal. The engine didn't even feel unusually hot.

I got the thermostat replaced the next day. All was well.

And now my car is again telling me that it's about to have a warp core breach. It's so weird, and it happens at the most random times: When I've stopped after going at freeway speeds, and then started up again; when I'm cruising at low RPMs in fifth gear; when I got home, realized I forgot something, and drove a couple blocks to the corner store - by the time I parked, the needle was hovering just under the orange zone! I'm starting to get the feeling that my car just likes to scare me, and is actually doing fine.

Has anyone else ever had this happen?

Edit: I think the compensation board might be going out. My mechanic agrees. After some further research, I have found some hearsay about running these cars without the compensation board, or with it bypassed. If it works, I would be happy to have a wobbly, but ultimately accurate, temperature gauge. Thoughts on this?

[mikealder]

The wiring between the ECT sensor and the gauge has shorted out to ground somewhere along its length, the lower the resistance the hotter the gauge reads, a dead short to ground will peg the gauge off the top of the scale - Mike

[BumbleBrick]

Originally Posted by mikealder

The wiring between the ECT sensor and the gauge has shorted out to ground somewhere along its length, the lower the resistance the hotter the gauge reads, a dead short to ground will peg the gauge off the top of the scale - Mike

This would explain the problem if it was topping out all the time... but it only tops out sometimes. Is it possible for the short to be intermittent?

[loki_the_glt]

Originally Posted by BumbleBrick

This would explain the problem if it was topping out all the time... but it only tops out sometimes. Is it possible for the short to be intermittent?

If the insulation is chafed it might flex enough to short in that fashion. We once had a mini-computer with ribbon-cable disk-drive interfaces and the insulation on one strand was nicked - the drive worked perfectly until it was pushed back into its carrier, when that strand brushed against the chassis and set the Write-Lock lamp off.
It might be possible to rig up an alternative wiring run as a test measure and see if the problem persists. If it goes away you've solved the problem; if it doesn't then you've at least eliminated the wiring as the cause of the problem.