Lan Vinh Do
Well Known Member
No fuel pressure drop for me anymore.
I had fuel pressure drop after climb as many other rv when i was turning off my aux fuel pump. As many other i had to keep my aux pump 1 or 2 min after level flight to prevent too much pressure drop. It was going down from 26 psi to 12. I thought before that it was the sensor that was doing this until i had a very perceptible loss of power for a fraction of a second when i was turning my aux fuel pump off.
So i can't pinpoint exactly what was doing this as i change many thing during my annual inspection. What i try before the inspection was the cooling shroud on the mechanical fuel pump and it wasn't changing much things.
At the annual, i did new fuel line from fuel selector to firewall. I change my electrical fuel pump to the new afp fuel pump. I Screw the filter directly in the fuel pump assembly ( with the modified fitting from Don ) and i remove the fuel flow sensor from the tunnel and put it after the throttle body. With this i pass from 6 fuel line in the tunnel to only 2 ( probably much less heat with less time in the tunnel and a lot less fitting )
I also did a air pressure test of my system and found a really really tiny leak from my gascolator .
So i did a long climb today to 10 000ft, turn off the fuel pump immediatly after levelling and no drop at all. It stay at 25-26 psi all the time.
So was it the fuel flow sensor that is now on the pressure side ( could induce vapour lock on the succion side) was it air suck by the gascolator, was it a defect in my old aux fuel pump, was it too much heat pick up by long loop of fuel line in the tunnel? I will never know but it was one of these.
It was a long annual inspection put i was glad of the result.
Also as many already reported, the fuel flow sensor is now rock stable and no variation at all with the fuel pump on or off
I had fuel pressure drop after climb as many other rv when i was turning off my aux fuel pump. As many other i had to keep my aux pump 1 or 2 min after level flight to prevent too much pressure drop. It was going down from 26 psi to 12. I thought before that it was the sensor that was doing this until i had a very perceptible loss of power for a fraction of a second when i was turning my aux fuel pump off.
So i can't pinpoint exactly what was doing this as i change many thing during my annual inspection. What i try before the inspection was the cooling shroud on the mechanical fuel pump and it wasn't changing much things.
At the annual, i did new fuel line from fuel selector to firewall. I change my electrical fuel pump to the new afp fuel pump. I Screw the filter directly in the fuel pump assembly ( with the modified fitting from Don ) and i remove the fuel flow sensor from the tunnel and put it after the throttle body. With this i pass from 6 fuel line in the tunnel to only 2 ( probably much less heat with less time in the tunnel and a lot less fitting )
I also did a air pressure test of my system and found a really really tiny leak from my gascolator .
So i did a long climb today to 10 000ft, turn off the fuel pump immediatly after levelling and no drop at all. It stay at 25-26 psi all the time.
So was it the fuel flow sensor that is now on the pressure side ( could induce vapour lock on the succion side) was it air suck by the gascolator, was it a defect in my old aux fuel pump, was it too much heat pick up by long loop of fuel line in the tunnel? I will never know but it was one of these.
It was a long annual inspection put i was glad of the result.
Also as many already reported, the fuel flow sensor is now rock stable and no variation at all with the fuel pump on or off