Binh

Hi guys,
I just replaced my fuel pump and I get 57 psi at the fuel line before fuel filter, Do you think this is too high or good? I also noticed the fuel pump run all the time when I driving, when ignition key on it won't on but if i crank it will turn on then when i shut off the engine it will shut off. Do you think this is normal ? This new pump is noisy than the old one.
Thank you

scope103

Technically, "who cares" what the pressure is before the filter. The spec at the rail is 33-37psi at idle (38-44psi static). http://personal.utulsa.edu/~nathan-b...87fuelpump.pdf That is what is set by the fuel pressure regulator, and that is what you need to measure.

So what you're measuring, effectively, is the pressure drop across the filter. 20psi drop does sound a little high to me, so perhaps it's time to replace the filter, but I've never measured it. And until you measure it at the rail you don't know either.

[When you measure the pressure at the rail, either at the larger corner connectors or at the CSI, remember that the crush-washers are one-time-use. Cheap at the dealer. Don't risk a fuel leak by reusing them.]

The fuel pump runs all the time while the engine is running (how else would it hold pressure in the rail?). But it does NOT run with key-on, engine-off. It starts running when you turn the key to STA (start), and then is maintained (via the COR) by the VAF once you get induction flow.