Vacuum on fuel filter
#1
Vacuum on fuel filter
After driving the truck 40 miles. The fuel pressure starts out at 14 psi then slowly drops as the truck warms up. Eventually getting to 23 in hg of vacuum at the filter. This has a new injection pump (second one), new carter lift pump. New pick up unit in the tank. Rewired the lift pump. Any ideas?
#5
#6
we ran a vacuum guage on the inlet of the lift pump and the vacuum stayed the same at 2 inches. At the same time we had a pressure gauge on the filter assembly and the pressure would start at 10 to 14 then slowly drop off to 0 then pull a vacuum while cruising. Gonna try another transfer pump.
#8
There was a fass on the truck and we were having the same problems and all we had available was a carter. The fass is a em990 can these be rebuilt?
---AutoMerged DoublePost---
put the new carter lift pump on and pressure etc was good and thot the problem was fixed. Drove 120 miles and pickup started surging, bucking etc. brought it back, hooked gauges up etc and had no pressure at the filter again. Had scanner on it while driving and it said the lift pump was running etc. No codes as far as timing on injection pump etc. We have put a new sender in tank, new fuel lines from lift pump to tank. On our second injection pump and second lift pump and still having these problems. Any info would be greatly appreciated.
---AutoMerged DoublePost---
put the new carter lift pump on and pressure etc was good and thot the problem was fixed. Drove 120 miles and pickup started surging, bucking etc. brought it back, hooked gauges up etc and had no pressure at the filter again. Had scanner on it while driving and it said the lift pump was running etc. No codes as far as timing on injection pump etc. We have put a new sender in tank, new fuel lines from lift pump to tank. On our second injection pump and second lift pump and still having these problems. Any info would be greatly appreciated.
Last edited by svitaks; 11-11-2011 at 04:52 PM. Reason: Automerged Doublepost
#10