09 1500 4.7 Fuel Pressure Leak Down?

[bryangt]

Im wondering if anyone can shed some light on this for me. My fuel pressure when running is 58-60psi and it holds this the entire time. When turning the truck off, the pressure drops to 50psi over about a 2 minute timespan, and after 2 hours it sits at 0. Is this normal? Should it hold? I have confirmed no leaking injectors or other fuel leaks.

 

[jws123]

Do you have a long crank on first start or something? If so you will need a new fuel pump they bleed off sometimes.

 

[bryangt]

If i wait for the pump to prime no, otherwise there might be a 1 second pause. What I'm most concerned about right now is a random misfire and rough idle/stall. But with the pump holding pressure it shouldnt be the cause I dont think.

 

[jws123]

If i wait for the pump to prime no, otherwise there might be a 1 second pause. What I'm most concerned about right now is a random misfire and rough idle/stall. But with the pump holding pressure it shouldnt be the cause I dont think.

4.7s are known to spit rocker arms off have you checked compression? also any codes? when was the last time plugs ect where done?

 

[bryangt]

P0300 is only code at this point. Both banks STFT are the same around -32% or so. Compression is good on all cylinders, or was prior to doing the seals/lifters.

Several weeks ago I did valve stem seals and lifters, plugs, wires, oil and filter. A week later it shut off when I came to a stop and has been like this since. I have now done my cats, 02s, cam and crank position sensors, evap purge, and map sensor. I havent heard any sound like a rocker popped off, but Im pulling the covers again this weekend just to make double sure. I have a throttle body to swap coming this weekend to test as well.

No vacuum leaks, fuel pump seems solid other than the eventual leak down, injectors arent leaking.

 

[bryangt]

In case anyone runs across this in the future, the EGR was stuck open. Noticed manifold pressure was around 90kpa.