fuel lift pump /ops

[george_01]

Missing or hesitation "sometimes" at heavy trottle and some times at idle. Stalls in about 20 seconds when opening fuel filter/water drain. Can't hear fuel lift pump running. When in other than park or drive, with ignition key turned all the way to start position it sounds like a solenoid clickking, same sound as on a gasser when battery weak or solenoid bad. What's my problem and how do I fix? Thanks in advance for your time and patients from this newbie. George

[george_01]

PS...The sound is comming from the lift pump itself. very rapid click.click.click.click sound that fades away to nothing after about 15 seconds. What does the fuel lift pump suppose to sound like? HELP PLEASE !

[george_01]

another PS... with motor running at idle speed. I opened the filter drain/water bleed off valve and get no fuel comming out and then the motor dies in about 20 seconds. is it the ops or the ops relay {do the relays go bad?}or is it the fuel lift pump? Trying my darndest to figure it out before I start buying parts! Thanks again

[turbovair]

OPS provides power to the lift pump when engine is running. During start, power is provided through the lift pump relay. If no fuel coming out when running, I would start with the OPS.

[tom.mcinerney]

The tapping sound from the LP which increases in frequency, then quiets...is normal--as the LP pressurizes the feed line, it bypasses/regulates to its float pressure; no more flow, no more tap sound.