Speedo & Tach die when car gets up to operating temps...any ideas why?
 

My guages have been working fine for years...up to now. :uhh:
After spending the day yesterday autocrossing, on my way home, I noticed my water temp guage creeping up ever so slightly. I put the heater on full blast just to be careful and cruised home (I was only two blocks away). during those two blocks, my tach & speedo died...they just dropped to "0" and stayed there. I let the car cool down, popped the hood when I got home, and didn't drive the car again until about 3-4 hours later, hoping the guages would work again. Nope.

This morning, I start the car up...obviously it was totally cool from sitting for a whole night...and oila! The guages work perfectly! Needless to say I was pleased and assumed that this may happen from time to time on track days, etc. which is OK with me, but about five minutes into my drive (typical warm up time) and the tach started moving erratically and...bam...they both dropped to "0" again. I'm assuming this is gonna happen everytime the car gets to operating temps.

Any ideas why this might happen? Anything would be much appreciated.

-Ian

None of the geniuses here have any hypotheses?

Your mission if you're up to it: figure out why engine heat affects the funtioning of the speedo & tach. (this message will self destruct in 15 seconds) :devil: :hf: :rl: :MissileSm

morning bump...