fuel filter?

[kdog]

Thanks for the response. My fuel pressure is around 55-56 and sometimes drops to 49 or so. the guys at tunex are thinking maybe the problem is not in the fuel system and come to find out they accually have not checked the injectors as they said "checking the injectors is a pain". Anything else you might steer me towards? or should I just let them keep checking stuff untill they (Hopefully) find something?

[RedHeartbeat]

You could have a pump that's about to fail, also. Be sure you have at least 1/2 tank of fuel to keep the pump cool and then put a test jumper to the pump. I'd run a jumper straight to the power lead on the pump from the battery and monitor the fuel pressure. It should be consistant. If it's not then you must find out why. Your test should involve the connections and the wires themselves. Run a length of wire to the connection at the tank and test there, also. It will have to be a good size wire to run that distance or be silver instead of copper to keep from losing voltage over the distance.

[RedHeartbeat]

Oh yeah, check your grounds from the pump to the chassis.

[kdog]

The pump was installed new a few months ago. Is there something that is causing it to fail or am I looking at the possibility of a bad pump to start.

Also sorry for the missinformation. It looks like it stays constant at 55 psi except for one drop right after startup.

Should I be concerned that I am not at 58 psi?

Thanks

[RedHeartbeat]

Depends on the accuracy of the gauge. Most aren't exact. If you can, compare your readings to those on another truck similar to yours. Does you fuel rail have a vacuum referenced fuel pressure regulator on it?

[kdog]

It does have a regulator on it. I spoke with a programmer since my long term fuel trims are at 16% at idle and 20% for the rest of the rpm band. He suggested that by bumping up the psi to 58 or maybe even higher that this would bring the fuel trims down. There still may be a programming issue on top of that but I was advised to do this step first.

What would you recommend?

[airdeano]

is that -16% idle and -20% cruise? suggests that the computer is constantly
removing xx% fuel to maintain its stioch. (rich)
or is that +16% idle and +16% cruise? suggests that the computer is
constantly add xx% fuel to maintain its stioch. (lean)
there is a big difference.
if you are having the +xx% yes increase the pressure to 60psi (by your gauge)
and referify your fuel trims... if they increase then your on the right track.
a -4% to -2% is desirable.
if you are having the -xx% yes decrease the pressure to 50psi (by your gauge)
and referify your fuel trims... if they decrease then your on the right track.

3psi is a 5% increase which should better your trims (5%)... a tamper-resistant T-5
bit is needed to adjust your pressure regulator.

airdeano