I have a 2001 QC Dakota (4wd, 4.7, 90k miles) that recently started taking
an extra second or so to start. I have a pretty new battery and the truck
turns over fast enough. I suspect fuel pump may be getting weak. I tried a
fuel pump pressure test and can see that I get about 20 psi itially when
starting cold, then after a second or so it makes it up to about 40 psi and
starts. If I try just energizing the pump cold I only get about 20 psi,
repeated energizing of the fuel pump gets me a little over 40 psi. Lastly,
whatever pressure I make it to, the pressure will slowly drop to 0 if the
truck is not running (i.e ignition on, or totally off). I am suspecting all
the symptoms here are with the fuel pump assembly (pump, relay, filter,
etc), but have some questions.
My questions.
1.Should the pressure be kept up when the truck is not running? (searching
the net says some vehicles are designed to only keep pressure when needed).
2. What psi should the fuel pump be providing?
Victor
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