Fuel Pressure

[RED1985]

OK guys I need a little help. I installed a fuel pressure gauge a month ago and I notice that whne it start up, even after it warm the fuel pressure is right at 5psi. After the run for 15 minutes or more the fuel pressure starts to drop very slowly. It drops all the way down to 2psi after 30-45 minutes. If I rev the engine the fuel pressure never reach back to 3psi, it might only increase .5 psi at most.

New fuel pump and all rubber fuel line replaced. I checked the length of the whole truck for any leaks and nothing.

Any help would be greatly appreciate.


1985 C10 350/700R4

[RED1985]

Anybody?
Anyone know of a website I might find any answer at? I tried a fuel speciality place but nothing was found after searching.

[bowtiemanchevyman]

check your cam lobe where the push rod runs on and the push rod. they might be worn out. when the motor warms up the oil thins out and the the space between the rod and the pump or the cam incresses and u loss pressure.

[RED1985]

Originally Posted by bowtiemanchevyman

check your cam lobe where the push rod runs on and the push rod. they might be worn out. when the motor warms up the oil thins out and the the space between the rod and the pump or the cam incresses and u loss pressure.

Thanks, I'll pull the fuel pump and check it out.

[hatzie]

Check it with a new US made fuel pump.

[pwradder]

is there a running problem also or is this just something you see on the gauge? if it is also a running problem, check for an in-line filter before the pump that may need replacement. good luck.