Fuel preasure
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Joined: May 2015
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From: Watertown, NY
Fuel preasure
Hey all,
I know there is a ton of threads out there about fuel pressure but I hope my issue hasn't already been covered so here goes. I got my truck back after having the tappet cover and fuel guage sending unit replace and my fp guage has been acting strange ever since. The first thing I noticed was I don't get as big of a spike when I turn the key on and the pump runs for a second. It's only like 5 psi max. I'm not sure what it used to be but I'm pretty sure it was higher than that. Next thing I noticed was idle pressure, it used the be 19-20 now it's 17-18. Finally is my driving pressures, it used to not drop below 16 unless I really got on it, now it's down at 15 with light acceleration and down to 10 if I Step on it. When I first got the truck back I had the number 2 fuel line leaking at the block and I thought that was the cause so I had it replace. Now I have no leaks and a new Baldwin pf7977 fuel filter. I also have a new vp44 return check valve on the way from Geno's to try. The truck seems to start ok and it runs like a dream. Has anyone else ever experienced anything like this? I don't know what fuel filter the PO was using, could the 5 micron pf7977 be causing that much restriction? Or something have got messed up with the vp44 when they had it off? Or should I be looking at the fuel tank since they dropped it to replace the sending unit?
Thanks in advance!
I know there is a ton of threads out there about fuel pressure but I hope my issue hasn't already been covered so here goes. I got my truck back after having the tappet cover and fuel guage sending unit replace and my fp guage has been acting strange ever since. The first thing I noticed was I don't get as big of a spike when I turn the key on and the pump runs for a second. It's only like 5 psi max. I'm not sure what it used to be but I'm pretty sure it was higher than that. Next thing I noticed was idle pressure, it used the be 19-20 now it's 17-18. Finally is my driving pressures, it used to not drop below 16 unless I really got on it, now it's down at 15 with light acceleration and down to 10 if I Step on it. When I first got the truck back I had the number 2 fuel line leaking at the block and I thought that was the cause so I had it replace. Now I have no leaks and a new Baldwin pf7977 fuel filter. I also have a new vp44 return check valve on the way from Geno's to try. The truck seems to start ok and it runs like a dream. Has anyone else ever experienced anything like this? I don't know what fuel filter the PO was using, could the 5 micron pf7977 be causing that much restriction? Or something have got messed up with the vp44 when they had it off? Or should I be looking at the fuel tank since they dropped it to replace the sending unit?
Thanks in advance!
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Joined: Jan 2003
Posts: 4,179
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From: The "real" Northern CA
If you havent figured this out yet..... What fuel pressure gauge do you have and how is it plumbed in the fuel system?
Did whomever replaced the fuel module happen to mention anything about the old one? Like was the module screen torn?
On your truck should be two schrader valve test ports for fuel pressure. Go get or have someone test the fuel pressure to be assured that your fuel pressure gauge in the cab is accurate. That may help understand where to look for the loss in fuel pressure.
Did whomever replaced the fuel module happen to mention anything about the old one? Like was the module screen torn?
On your truck should be two schrader valve test ports for fuel pressure. Go get or have someone test the fuel pressure to be assured that your fuel pressure gauge in the cab is accurate. That may help understand where to look for the loss in fuel pressure.
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