Wrong CHT temps

[tominidaho]

I am consistently showing (EIS 2000) CHT's of 800 plus degrees, while my old steam gauge, re-installed until yesterday, shows the usual 180 to 230 degrees. It seems to show high by about a factor of 4. I have triple checked my install, everything is correct. I am using the probes supplied by GRT for the Rotax 912S. These probes are grounded to the same direct ground that the EIS power supply is grounded to (not the airframe).

A couple days ago I sold the CHT steam gauge along with others, so now I am flying around without accurate #'s, but I know how to interpret the erroneous #'s enough to keep me out of trouble, but obviously this is a short term solution. Other's have suggested is a programming error, the unit was setup incorrectly at the factory. Is there a way I can deal with problem without having to re-install a whole different unit? Or should I just continue to do the math, divide by 4 whatever number I see, to get the correct value? That's a joke, I hope

[Bobturner]

Is the Rotax set up different? For Lycomings the CHT probes are not grounded, both wires come back to the EIS

[tominidaho]

Bob,
Halfway through reading your response, I realized where I had gone wrong, and went out to the hangar to confirm it. I had somehow construed the wiring directions so that I had the white wire from the sensor going to ground, not back to the EIS. Powering everything up confirmed the now correct reading: CHT of 74 degrees, just like the EGT, while parked in the hangar. My bad! If we ever meet I owe you your favorite beverage, seriously, thanks Next question, when am I getting my Mini?? Ha ha.