I have a Westach egt\boos combo gauge tapped on the exhaust manifold.

Sunday I noticed it was not working while I was going down the highway. It was sitting on zero. I then noticed it would climb up to 500, and hang there for a minute. Then it would drop to 200, then to zero.

This morning on the way to work, it never went to zero. But it never got over 500 @wot., and it stayed at 500 while cruising.

The boost is working fine.

I am wondering if its the thermocouple.

 

Check your wiring. Make sure everything is tight. If it's not shorting out somewhere, then it sounds like a bad thermocouple. If ya need one, I got an extra one you can have.

 

It worked good on the way home from work last night, but it acted up this morning. It looks like it is running about 200 degrees off.

I guess a new thermocouple is due. I havent had time to run down the wires yet.

 

I have had the same problem and it was a connection on the back of the gauge .... if you can get to it when driving put your finger on the pyro wire on the back and put a little pressure on it and watch the gauge temp spring up or down. I recrimped the wire to the gauge several times but it always seems to do it again in time.

 

so replacing the thermocouple is what you did? or was it the gauges fault?

 

I've worked on quite a few pyros that were acting up, every single one was due to a bad connection. Thermocouples are tough and rarely fail.