is it my fuel pump?

PhantomXJ1

New Member
Joined
Mar 8, 2008
Location
Wake Forest
so I finally got the front axle buttoned up. new spicer shafts, new balljoints, one new wheelbearing unit. cranked it up fine rode down the trail and after about 5-10 minutes into the trail it shuts off. no problem, its done this once before, I'll just crank it and keep going. well once I get onto the second trail it just shuts off. I got uneasy that it did it twice so I cranked it up and wanted to turn around and go back home. I couldn't:

once it finally cranks up it runs fine, you can go through the RPM range and it runs/sounds fine. you can let it idle, it runs fine. but as soon as I put it in gear (reverse or drive) it cuts off. when the engine is off and you turn the accessories on, you can here the fuel pump engage and sounds strong/fine. how can I tell whats shutting my jeep off? is it enough fuel pressure to run the engine only(nuetral)? roomate seems to think thats the deal. that when you put it in gear, it always drops off in RPMs, that the fuel pump isn't putting enough gas in there to run it that low.
 
so I finally got the front axle buttoned up. new spicer shafts, new balljoints, one new wheelbearing unit. cranked it up fine rode down the trail and after about 5-10 minutes into the trail it shuts off. no problem, its done this once before, I'll just crank it and keep going. well once I get onto the second trail it just shuts off. I got uneasy that it did it twice so I cranked it up and wanted to turn around and go back home. I couldn't:
once it finally cranks up it runs fine, you can go through the RPM range and it runs/sounds fine. you can let it idle, it runs fine. but as soon as I put it in gear (reverse or drive) it cuts off. when the engine is off and you turn the accessories on, you can here the fuel pump engage and sounds strong/fine. how can I tell whats shutting my jeep off? is it enough fuel pressure to run the engine only(nuetral)? roomate seems to think thats the deal. that when you put it in gear, it always drops off in RPMs, that the fuel pump isn't putting enough gas in there to run it that low.

vacuum leak with something to the auto tranny?
 
Any codes? Start by doing the key on off on off on to get codes. Also look at all wirring that may be shorting out when the engine moves when u put it in gear. Use a fuel gage to test the pressure, shoud be about 38 psi. Also see if it is firing related.
 
I put a pressure tester on it and it was reading constant at about 21psi. when the vehicle is first turned on with the tester on it. instead of it coming up almost right away, it creeps up. I couldn't get it to cut off like it was doing last night, but it did do it a few times. only thing is, fuel pressure never really hiccupped on the guage. I just put a new fuel filter on there a few weeks ago, made a trip and found out the rubber hose that is about two inches long had a cut in it. I'm wondering if there is just a clog somewhere that is allowing enough gas to run, but not enough to run while its under load. I know it takes alot more fuel pressure to run in gear than in nuetral.
 
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