What should my fuel pressure be?

[1629dill]

I am working on a problem with Hesitation when cold.
I have check the fuel pressure at the filter an I have 6 to 6.5 psi.
Is that good?

[john8662]

Yeah, that's fine pressure, are you using a fitting on the filter element or out of the water drain petcock?

It will be lower out of the filter than out of the petcock because of the restriction of the filter.

The pump makes 8psi at the pump itself, so 6-7 at the pump is what you'd expect.

J

[JohnC]

Anything greater than zero at the injection pump inlet is OK.

[Hubert]

Yeah, it'll fluctuate pressure a good bit depending on demand. Its best to check during all driving conditions and as long as you can maintain some positive pressure during high demand you should be good. It'll dip pretty good from sudden full throttle acceleration up through about 2500 rpm. It should recover quickly.

[MRBACHAND]

Yeah, that's fine pressure, are you using a fitting on the filter element or out of the water drain petcock?

It will be lower out of the filter than out of the petcock because of the restriction of the filter.

The pump makes 8psi at the pump itself, so 6-7 at the pump is what you'd expect.

J

Water drain or filter top are both unfiltered sides of the filter manager. In order to know for sure what your IP is getting you need to test the filter manager to IP hose, where fuel pressure gauges should be installed.

There is also a small screen on the IP inlet which could get crudded up over time by filter mishaps when changing filter, or rotting hose from FLT MGR to IP.

Only way to check that is to pull the fitting and inspect the screen.