Noisy lift pump

[Frank V]

Hi Dr. Lee,

I have been noticing that my lift pump seems noisyer than ever. Also, twice in the last month the engine quit with no reason but started right back up. Its like someone shut the ignition off. Could the lift pump be going out?
Frank

[CleviteKid]

Hi Frank,

What year is your truck, and does it have the electric lift pump? Once the engine is running, under most conditions it can suck fuel from the tank thru a dead lift pump, but not if the filter is blocked.

Let us know what year, and when you last changed the filter, and we will see what help we can provide.

Dr. Lee :cool:

[Frank V]

Oops. Sorry about that. 1996 K2500. Filter changed about 20,000 miles ago. Injector pump is green tagged and the shut off solenoid changed the same time the filter was changed. About three years ago. I'm pretty sure the lift pump is electric since I hear that rapid ticking noise while waiting for the glow plugs to let me start. Its loud enough to make a passerby stop, look and wonder what the noise is. At least until I fire the motor up.

[jbplock]

Frank,
IIRC there is a valve and hose near the coolant crossover on the front of the engine that is used to drain the fuel filter bowl. A quick way to check the lift pump is to crack this valve when the engine is running... If the engine stalls it's an indication that the lift pump is not working.
smile.gif

[tom.mcinerney]

Yes, and Frank, with this type pump it's quite noisy (and max delivery volume) with no backpressure. As pressure rises, the solenoid stroke diminishes, and the loud ticking subdues to a muffled "brrrr". If < 4psi at drain referenced in post above , replace filter and try again.