Wacky EGT guage??

[XJSuperman]

I've had my EGT guage in my new truck for about 2 months or so and it's recently started to act weird.

Seems before the engine is fully warmed up (first 15-20 minutes or so) the needle will all the sudden dance and wiggle all over and sometimes go dead completely. During this time when it;s not acting up it seems to work fine and then after 20 minutes or so it works just fine and continues to work fine the rest of the day.



I've checked and rechecked my wiring, connections... have'nt pulled the probe yet but don;t see any reason to do so. It's an autometer ultralight guage.



Anyone know why it may be doing this?



Thanks,

Jason

 

[AndyMan]

I've seen a couple of problems with Pyro's, and had a problem with my Di/Pricol recently. I can give you some things to look for. It's the weirdest thing to see that needle bouncing around like that. I'd stomp the pedal, and it would drop 300 degrees instantly, then jump about 800 degrees 2 seconds later. weird...



anyway, here's some stuff to try.



1. Check the resistance of the thermocouple. The tc has two wires that run to the gauge. Pop your gauge free from the wiring harness. Have a buddy put the red lead to one of the wires from the thermocouple, and the - lead to the other wire. Then get out on the road and floor it. I can't remember if it approaches infinity the hotter it gets, or the cooler. Either way, your idle resistance reading should vary WILDLY from your WOT resistance reading.



If you get the wild readings, your thermocouple and wiring are good, and most likely you have a bad gauge. However, if you don't get a wild reading on the meter, then check the little screws and nuts that connect the thermocouple to the wiring harness (in the engine compartment about 12 inches from the thermocouple). You may want to take them loose, clean them with some contact cleaner, and put them back together. (this was the problem with mine). I good heat-shrink tubing over the connectors will help slow the corrosion and assist with keeping good contact in the wiring. Some dielectric grease may also assist with that joint.



Hope that helps!!

Andy