Erratic EGT behavior

[JayLo]

Have any of you guys with EGTs experienced gauge flutter and/or very low (200º F) readings? What the hay causes it? I have an Autometer and it’s been acting like a son-of-a-b*tch. It will work fine for a month and then act all weird while driving. I added an RF noise suppressor (big ole Radio Shack one) and insulated the hell out of the wires by the A-pillar (even coated the metal A-piller with insulating tape). All of the connections seem to be tight. This is frustrating as hell. It’s a sensitive device, yes, but it’s not rocket science.

[TheRock]

I know that length of the wires are critical, so make sure that they haven't been shortened or lengthed, and make sure there are no incisions into the wire anywhere.

Other than that, I would blame the gauge before the thermocouple, but possibly AutoMeter would be of help on that. Possibly call their tech-support and see what they say.

[JayLo]

The wire length is unaltered. I took care to avoid damaging the insulation as well.

As it turns out, I called Autometer. They said to disconnect the thermocouple probe and see if the pyrometer read around 25º F with power to it, which it did. Another call presenting my findings resulted in them shipping me a replacement probe, which will hopefully be here soon.

Could I have possibly over tightened the thermocouple probe, damaging it in the process?

The threaded diameter gets slightly larger the further it threads in the hole, and I cranked down on it pretty good, hoping to avoid a potential exhaust leak.

Anyone have a recommended torque spec or good rule of thumb for threaded pyros?

[boosted]

Chech for a good ground at the body and the block..my gauge went all wacko for a while until I found that the ground at the body was corroded..cleaned up the connections at both ends and
voila. If you can add a few extra ground straps from the body to the engine it may help. Just a thought

Chris

[JayLo]

Hey, thanks for the input, guys. Autometer sent me a new probe free of charge, which I installed tonight. Apparently, I must have over tightened the original probe (shhhh, don't tell Autometer ) and damaged the thermocouple. The new one works like a champ. It was very odd, however, how the old one would work sporadically. Thanks anyway.

[igotaneed4speed]

so by shorting the wores on the senders for the autometer guages it'll change the reading, so i take it the guage is cal. for the ressistance in the whoel length of the wire if so opppsssssss.......