One really hot cylinder

n505at · #1 10-31-2008, 11:11 AM

While on taxi back to hangar on Tuesday I noticed No 1 CHT way off scale at over 600 deg. All other cylinder were nominal, EGT was nominal. On taxi to take off yesterday, I noticed same thing. Run up temp was nominal. Went flying anyway and flying temp was nominal. But it went off scale again on taxi back to hangar. I have not yet taken off the cowl to look for any problems. I think it may be a sensor problem. I've emailed Advanced Flight but not response yet. Any ideas?

RV7A, 30 hours on new Lyc O-360, Lasar ignition, ACS 2002 engine monitor.

Thanks for the help

Roy Samuelson
Oakland CA

N941WR · #2 10-31-2008, 11:36 AM

Roy,

You are the second person who has asked about 600*F on one cylinder with an AFS.

Did it peak and come right back down or did it go up and stay up?

The guy I was talking to had it peak and a second later it was back in line with the others. This behavior probably indicates a sensor issue rather than a true high CHT.

When you get back, try swapping CHT probes and see what happens.

It is unlikely you have a 600* CHT taxiing in because you had been at idle for landing and taxiing doesn't take much power.

Just my $.02

painless · #3 10-31-2008, 11:46 AM

Sounds like a sensor problem. I had the same thing happen to me with my RMI micomonitor. I have a molex disconnect from a selector switch (the monitor only displays one cylinder at a time) to the monitor and one set of pins was making intermittant contact. Acted just as you describe.

Roy Samuelson · #4 11-02-2008, 01:56 PM

Rob at Advanced Flight emailed that it sounded like a sensor or wiring problem. I switched the sensors on the #1 and #3 cylinders. I taxied about 3/4 mile to get gas with no problems. So who knows what the original problem was. I did note that the sensor in #1 was a little loose when I took it out.

Roy Samuelson