GRT Avionics

My manifold pressure isn't working correctly. Takeoff numbers are fine but the indicator doesn't indicate below 23 inches even at flight idle. It has worked fine for 450 hours. What is wrong? Thanks, RV 6 with O-360 constant speed prop.

Check for tubing leak.

I also have a MP problem, for 350 hours on my 914 Rotax, no problem but last few days, I throttled back from cruise rpm. To descend and my warning light come on for only a second, then at idle on the ground, I notice it will jump from 3 to 13-14 inches at idle but all looks ok above 1700 rpm. Removed the long sensor vacuum hose from sensor and noticed-the little 1/2 long adapter hose attached to the sensor was mashed shut, I replaced it and still have same problem, possibly it is the unit, so I have sent it back to GRT for testing. Just got word they are sending a new sensor for me to try.

I ordered a new sensor, which come with a new plug, I noticed my old grey plastic plug on old sensor did not plug in all the way, but I did not know that, for first 350 hours, I tried the new silver plastic plug on the old sensor and it plugged in all the way, so I think the EIS readings are correct now, and all my erratic manifold readings were because the old grey plug that had come with my old sensor was not made proper from the beginning, which was just getting a bad connection. I now have a new sensor, that I did not need.

Wayne.