mistergerf
Active Member
I've noticed fluctuating fuel pressures recently. I'm fairly sure that its related to ops in high OATs. Here are the symptoms:
Normal fuel PSI is around 26 psi - pretty solid indication the majority of the time. At high OATs I first notice that the decimal on the psi readout starts flickering up and down a few tenths. Then I start noticing pressure excursions down as low as 11 psi for 5 to 10 seconds and then recovering to about 24 psi and then continued flickering of the tenths with the occasional excursion. No change in engine power during flight although I do notice some engine surging on the ground, at my destination, ranging from 800 to 1,100 RPM.
Am I looking at fuel vaporizing in the lines ?
What are my options for preventing this ?
(Here are the tech details:
AF2500 engine monitor. Standard Vans fuel pressure manifold on the forward side of the firewall connected to the mechanical fuel pump. Aerosport IO-320 D1A, AFP fuel injection with purge valve and HP fuel pump filter on the cabin floor (not running). Fuel lines FW forward are all sleeved with the orange stuff. OAT ~ 90 deg F. CHTs 375 - 405, EGTs ~1,300, oil temp ~ 205, 65% power. Basically nothing is red-lining, even the fuel PSI is within tollerances... but ...)
Any thoughts, panic warnings, suggestions ... ?
Gerry.
(N696WG, RV-9, 145 hours)
Normal fuel PSI is around 26 psi - pretty solid indication the majority of the time. At high OATs I first notice that the decimal on the psi readout starts flickering up and down a few tenths. Then I start noticing pressure excursions down as low as 11 psi for 5 to 10 seconds and then recovering to about 24 psi and then continued flickering of the tenths with the occasional excursion. No change in engine power during flight although I do notice some engine surging on the ground, at my destination, ranging from 800 to 1,100 RPM.
Am I looking at fuel vaporizing in the lines ?
What are my options for preventing this ?
(Here are the tech details:
AF2500 engine monitor. Standard Vans fuel pressure manifold on the forward side of the firewall connected to the mechanical fuel pump. Aerosport IO-320 D1A, AFP fuel injection with purge valve and HP fuel pump filter on the cabin floor (not running). Fuel lines FW forward are all sleeved with the orange stuff. OAT ~ 90 deg F. CHTs 375 - 405, EGTs ~1,300, oil temp ~ 205, 65% power. Basically nothing is red-lining, even the fuel PSI is within tollerances... but ...)
Any thoughts, panic warnings, suggestions ... ?
Gerry.
(N696WG, RV-9, 145 hours)