zj loses prime on fuel system

CThurmond

CThurmond

Well-Known Member
Joined
Aug 6, 2010
Location
china grove nc
Ok i have a 93 grand cherokee

it has the inline six engine

i have put a fuel pump in it, actually two.
i have put a fuel regulator on it
i have checked the fuel lines for leaks

everytime i turn off the zj it loses prime after 5 mins

then i cant seem to get the fuel pump to turn on by just turning on the cars power switch, i can hear the pump whine when it turns on. it takes two to ten minutes of turning the car on and off

two fuel pumps , and a regulator later, no solution

please help
 
losing prime not as big a deal as fuel pump not coming on, it should come on every time you spin the motor. if it doesnt do that then swap the starter relay with known good. still no good, chase the fuel pump circuit in the schematic
 
Wouldnt it run terible if they were leaking? I removed each injector harness n it idked way down each one

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It can spray fine when its running, but with the engine off the injector will leak down after sitting. Can make it take longer to start because the fuel pressure drops. If they are leakin bad it can leak all the fuel in and flood the engine causing it to take even longer to start. Try cranking just a few seconds, turn the ignition off and try cranking again. This is what I do to my TJ but I believe the fuel pump is starting to go bad. Usually fires right off if you do that, usually.


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Ahhh I misread the original post.


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CharlesB36 said:
losing prime not as big a deal as fuel pump not coming on, it should come on every time you spin the motor. if it doesnt do that then swap the starter relay with known good. still no good, chase the fuel pump circuit in the schematic
Click to expand...
i meant fuel pump relay, not sure why i said starter. sounds like pcm isnt seeing start signal, and is instead waiting for the oil pressure switch to turn the fuel pump on, if it is even set up like that. again.. a haynes manual and wiring diagram should make it fairly simple to find the problem. about the losing of the prime. do you see the fuel pressure drop substancaill on a fuel pressure gauge or just basing it on the fact that it wont start?
 
Fuel rail would have no pressure in rail, hit value n nothing comes out.

Mechanic at shop ran down all the ground s and told me to get a computer , so when my wallet recovers from 200 diagnosing charge ill pop s new one in

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