Noticed that after cold start, then taxiing to the fuel pumps, shut down, leave mixture at ICO, when I go to re-start, the fuel pressure is around 80psi. Seems a bit high, but drops to normal (about 25 psi) as soon as mixture is pushed in. Just wondering if this is is ok, since I always leave mixture at ICO after shutdown or should I release the pressure?
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high oil pressure after shutdown
- Thread starter Jake14
- Start date
skylor
Well Known Member
Yes. Fuel heats up between the pump and the fuel servo and the expansion increases pressure.
A very bad idea. An inadvertent engine start from an ungrounded mag or ignition switch left on while the plane is unoccupied with the engine set at full throttle and mixture can lead to a disastrous outcome. It has happened before...
Skylor
hgerhardt
Well Known Member
This is the exact scenario which probably caused the leaky Kavlico fuel pressure sensors and led to the service bulletins of Dynon and Garmin to replace the sensor with a 'better' one.
Jpm757
Well Known Member
I have upgraded both my planes with the 0-150 psi improved Kavlico sensor. I too will see a fuel pressure increase to about 45 psi after shutdown. Simply going to full rich mixture momentarily after shutdown will drop the pressure to zero, then return to Idle cut off. I will get a few drops of fuel out of the sniffle valve (IO-360).
Yes, I understand the risks with that technique.. that’s why I was hesitant even mention it. You could reduce the potential run time in the event of a start by turning the fuel selector to off, but I was really only suggesting it more of a temporary troubleshooting technique than a way to park the plane unattended..
My bad....it's about fuel pressure, but I can't find a way to edit the title.......
Still wondering if it's a bad idea to just leave the engine shut down with the high pressure, ie., is there some chance of damaging something?
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my fuel pressure does exactly the same. high pressure causes high stress on the components. i don't know if that's a real problem or not but it sure doesn't cost anything to push the mixture in after shutdown. just for a few seconds and then pull the red knob back.
