I have a problem I was wondering if anybody could give me any advise on. I have a late 01' 2500. I have a fuel pressure gauge in the truck and latley the fuel pressure will not regulate on anything. The truck idles at 14 then when accelerating it will go to 11 pounds of pressure, the problem comes as I am going down the road, the pressure will start to jump, the needle will go from 13 all the way down to 6 almost in the red. I have new lift pump on the truck and an injector pump that has maybe 11,000 miles on it. Just last night I was filling up and as I left the pump and pulled on to the freeway, I went from having 11 pounds of pressure to 6 again. Please offer any advise you have, I would appreciate it.

-Karlie Ann-

 

Do you have an isolator on you guage line. If you do get rid of it. Get a needle valve from local hardware or auto store. Plumb the needle valve in there and run fuel into the cab, have the needle valve open about 3/4 of a turn only. If that dont fix it its possible your lift pump is starting to die. Do a search on jumping fuel pressure and you will find bunch of info.

 

I feel your pain, I have the exact same symptoms. 15 psi idle ~9 WOT and then all the sudden ~9 psi idle and ~3 WOT then back to normal. I just dumped the isolator today for the needle valve and the symptoms are still there Time to start shopping for a Walbro or Fass or something, the stock LP was only 10 months old and about 12,000 miles. As a last question I tapped off the VP using Geno's kit on the shrader valve, is there ANY way that could be causing the fluctuation? Long shot here but with the vibration of the engine could the needle in the shrader valve ware down not allowing fuel through the lines? My symptoms seem to only happen while at WOT and will return to normal with a WOT run. While at WOT more fuel is being used causing less pressure maybe causing the shrader valve to close some?

Love this truck but hate the fuel system. Hopefully I haven't toasted the VP yet.