Fuel pressure drop

hi Steve,

You're on the right track, but if this doesn't work it could be the fuel pressure regulator. I just had a 912iS with the same issue and it was the fuel pressure regulator. It's costly, but only take a couple of minutes to change. If you have another 912iS around mabey you could borrow their regulator and give it a try.

Agree with Roger and add -

Sensors in small aircraft are prone to erratic readings.

If you are able to implement Rogers suggestion, it may indicate a failing fuel pressure sensor, rather than a problem with the regulator.😈

Hmm—fuel pressure sensor... I ordered a fuel pressure sensor from Aircraft Spruce (AS) in January. The unit I received had some white gunk in the threads. I asked AS about it, and they assured me that it was in fact new and not a return. It's a little hard to see in this photo, but you can see some white material in the lower 5 threads on the sensor. This is how it arrived from AS. 

I haven't done the other tasks in my list yet, and this may not be fair, but now I'm immediately suspicious of the fuel pressure sensor. 

Did they send me a defective unit someone else had returned? Total runtime on my engine (just testing) is ~20-30 minutes.

One other note—while running the fuel pump(s) to pressure check my fuel system, I sometimes heard a slight hissing sound. It sort of sounds like a super fine leak, but I've checked the fuel system many times, and there's no fuel leakage. 

What about your warranty? (In the US?)

I would call Lockwood aviation in Sebring, FL and get their input. They can also handle warranty claims.   

Yeah, the goo on that looks like it was threaded in previously.  I’m not an AS fan. 

The sensor does look like it was used. The threads should be clean.