after shut down, my fuel pressure quickly drops to zero after just 2 seconds. is there normally pressure left in the line? i had a no crank after it died after driving for an hour. after 8 hour sitting, it started after many cranks but died after gear select. finally started after much cranking but kept giving me trouble. wondering if the fuel line to IP might be getting cracked and either letting in air or leaking fuel, but no drips so far.
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fuel pressure after shut down....
- Thread starter deejaaa
- Start date
Normal for it to drop to zero. I believe any built up pressure would escape back toward the tank as the LP is flow on fail.
schiker
Well-Known Member
Mine holds a bit of pressure for a while never measured time it takes to bleed off Unless my guage just slowly drops needle??? I do have an electric one so unsure if its actually pressurized. When I key on run and wait to start my LP runs and shows pressure near instantly but when I start guage resets to zero while cranking and rebounds when I release from start. I don't think your LP runs initially with key "on run" does it? Might put it in gear and key on run while wait to start then shift to neutral to start to fool LP to "pre run" and see if that makes it start easier.
schiker
Well-Known Member
Or is it put in gear key on start to pre run your LP?
not sure. this is the 93.
Pressure leaks out through the transfer pump and IP back to the tank and back through the lift pump. My 1993 hold pressure longer. Suspect leaking valves in lift pump.
Lift pumps on 1993 only run from the OPS or during crank.
Lift pumps on 1993 only run from the OPS or during crank.
New parts may not have fixed the problem. If your tank sock is restricted then it is bypassing. This means the lift pump eats a lot of dirt. Should be under warranty...
You can see and smell fuel leaks this bad. Fuel does evaporate off hot parts so you may not see a drip.
A 10 micron filter before the lift pump can restrict it.
I would say mine holds pressure and slowly goes down in 30 seconds or so. It stops at like 2 PSI for awhile.
i have no sock left:
http://www.thetruckstop.us/forum/sh...ke-down-again!&p=397900&viewfull=1#post397900
http://www.thetruckstop.us/forum/sh...ke-down-again!&p=397900&viewfull=1#post397900
HighSierra86
Active Member
Mine holds pressure after shut down for much longer than 2 seconds. It is more of a slow drop, but it does start dropping immediatly.
-Nick
-Nick
buddy
Active Member
Could be your IP return fitting is not holding the 4.5psi its supposed to, as discussed in another thread. Or its just going back to the tank through the LP.
Where is your pressure gauge located?
Where is your pressure gauge located?
bison
Well-Known Member
Fuel system is not supposed to hold pressure after shut down.Most LP's have a lousy checkvalve.
The fuel system is closed loop and will stay full of fuel unless there is an air leak somewhere.
A Clear IP return tube that stays full of fuel(one little bubble after shut down is normal) lets you know at a glance that the system is OK.
The fuel system is closed loop and will stay full of fuel unless there is an air leak somewhere.
A Clear IP return tube that stays full of fuel(one little bubble after shut down is normal) lets you know at a glance that the system is OK.