P0091 after Pressure relief valve line came off

Matt Dickey

Matt Dickey

Greenie N00B Member
Greenie Member
Okay so i was doing tuning pulls last night for Will at PD i was in 4th gear and put the hammer down around 3k and went all the way to 6k ish and let off and shifted to 6th to coast and shed some speed to get down and do another pull, about 1/2 mile down the road i made my way down to 4th again and let the rpm drop down and went to log another pull and up until this point i was decelerating and everything felt fine but as soon as i dropped the pedal again something was very very wrong. i hit maybe 2psi boost and thats it. i started smelling raw fuel so i pulled over and shut it down and inspected under the hood where i found the line coming off the Pressure Relief Valve was leaking and if memory serves correct it was pushed off of its correct position on the valve. i started it up and limped it home and even after the engine was shut off it continued to leak fuel from the pressure relief valve until all fuel pressure was gone. I have since replaced the hose from the pressure relief valve to the HPFP it no longer leaks however i have 100psi or less at idle and im flagging a P0091 code. ill attatch the 2 logs i took both during the failure and after the failure.
 

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You can get the motor hot enough to test the prv by idling and you have enough fuel pressure to do that safely
 
One of these days I need to get a full factory car to do a full HPFP how to. Someone mail me their car plz kthx.
For the spillvalve: Actuate the needle in the spill valve itself with your thumb. If it feels like it's sticky or breaking free, it's in need of cleaning (and you probably need to change oils). Check the button next:

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If any of that three piece assembly is sticky, clean it with lighter fluid then lubricate with redline injector cleaner. If the button is stuck down, you won't make any pressure. If the spill valve needle and the button move freely and aren't sticky then you probably need a new PRV.
 
If you want to fly out here and do mine it's stock with 125,000 miles on it
 
It was the PRV i took the hpfp apart and the springs were free moving so i pulled the PRV and could easily blow air through it like a coffee straw so i got a used one and installed it and the problem is fixed. Thank you enki
 
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