Hi,

MP needle started flickering in flight once in a while, now much more.
Its flickering is of about half an inch but last flight increased at times to maybe 2”
Engine smooth. JPI MP stable.

Ideas for the cause?

Electrical, the wiring is going to ground somewhere or failing pressure transducer maybe !!

Mapleflt wrote:Electrical, the wiring is going to ground somewhere or failing pressure transducer maybe !!

I'm assuming that since he said he's JPI shows stable that it's his mechanical guage flickering. I'd bet it's a bad guage or something partially plugging that MP line.

A1Skinner wrote:

Mapleflt wrote:Electrical, the wiring is going to ground somewhere or failing pressure transducer maybe !!

I'm assuming that since he said he's JPI shows stable that it's his mechanical guage flickering. I'd bet it's a bad guage or something partially plugging that MP line.

True; good point so yes, something mechanical.

I'm guessing a cracked MP line or a loose fitting, and it's getting more cracked / looser.
Maybe disconnect the line at the gauge, lightly pressurize it,
then apply soapy water to the line & look for bubbles.

Thx Hotrod,

We inspected and flushed the lines, the one from the manifold to the firewall appeared to be a little dirty.
Could not find any cracks.

Flew and all Ok until setting cruise power. Maybe coincidence but flickering was milder.
Something at the fittings?

Thinking about getting another gage and if it continues change fittings and lines.

Did find a small crack in the copper line at the very end of it going to the manifold.

Q. Can those copper lines be replaced with better ones to avoid this happening again?
First time it happens to me but still...