Engine Hiccuped Above 15,000'

[jnisley]

Yesterday on my flight home to Meadville, Pa KGKJ from Independence, Iowa KIIB I climbed into the teens to catch a good tail wind and avoid dealing with the chaos the Chicago area is facing with Chicago Center being out of service, as I was approaching 17,000' my engine started hiccuping slightly, I immediately descended to 15,500' but it still occasionally hiccuped (it never actually sputtered), I noticed my fuel pressure needle would wander from 22-27lbs hold steady at 27lbs for a while then wander again and the engine would hiccup every five minutes or so. (When I used the electric boost pump the pressure held steady and the engine didn't hiccup) I descended to 13,500' and the hiccuping stopped along with the wandering fuel pressure.

Earlier this summer I did a test flight up to 18,000' and everything was fine.

Any ideas?

[carusoam]

Sounds like you have identified the problem...?

An aging diaphragm in the engine driven fuel pump could be the specific problem.

Is there a good way to ground test the fuel pump?

If the diaphragm has a split or tear or hole it may leak out a vent at the back of the pump...?

Discuss that with your mechanic...

As usual, I am a PP, not a mechanic.

Best regards,

-a-

[N201MKTurbo]

I had the same problem. I rebuilt the fuel selector and it got better. The hiccup happened when the fuel pressure got low. Switching tanks made it different.