BillProctor

My son bought this jeep last week not running and now he trying to get it running. The fuel pump will not come on. We have swapped the pump from his other jeep(same model/year) that is running with no luck. The pump is not coming on. We have gone thru all of the relays and fuses under the hood. My fords have a cutoff switch but jeeps apparently only have the relays. Is this true. All of the wiring looks good. Can I get a few Ideals on what might be the problem with it. All suggestions are greatly appreciated.

okcjeeper

Did you get a volt meter out and test the sender and the connectors an such where there pump/sender plugs in?

BillProctor

yes we did we check all the relays and fuses then even switch fuelpumps with another one and still nothingthe oringial pump works wtih the other jeep and the new one does not work with this 92 jeep

okcjeeper

Did you check the fuel pump sending unit plug itself? or did you switch those as well? If so then somewhere between the plug that plugs into the sending unit to where ever is shorted out or something.

jpdocdave

have you checked spark and injector pulse. if you haven't, and find you also lost spark and pulse you probably have a bad crank sensor

okcjeeper

Good call didn't even think about that.

BillProctor

i'll try it let ya'll know later thanks

BuckB91XJ

Are you even hearing the pump prime when to switch the ignition to on (before starting)??? That is a buzzing sound that comes form the rear. You should be able to hear it inside the cab. If you aren't, you definitely have no power going to the pump itslef. If you have checked all the plugs and relays, then you do have a broken or shorted wire somewhere. Unfortuantely when talking fuel pump that could be anywhere from the nose to the tail.

bigwheeler

im having the same problem but ive been dealing wit it for the past 2 years and finally i just did something bout. i changed the fuel filter because it was so plugged that it wasnt allowing the fuel to get to the engine i found this out by putting a pressure gage on the engine and it should have at least 45 lbs going to it. so try changing the fuel filter. now it runs like a dream.

okcjeeper

Plugged fuel filter can cause that but I think his issue is he's not even hearing the fuel pump attempt to prime. It should still come on and attempt to prime even with a plugged fuel filter. If ya don't hear the buzz when you turn the key to on position the pump is not coming on at all.

gabe

I also have a 92 ,and had the same problem to the tee.check and see if you have spark,if you dont then it is probably the same problem i had.which is the computer next to the air box on the drivers side fender is going bad.beleive it or not but i was told to take mine out(which only takes about 5 minutes)bring it inside get it nice and toasty warm (i put mine on a heater vent for about 15 minutes)put it back in right away and see if it fires.and mine fired right up.so i got one at a junk yard for 30.00 bucks,and have been fine since.my old one will work in warm whether but not in the cold. Hope that helps

bigwheeler

or it could be that he does not have a good ground running to the pump or the relay box

BillProctor

yea i switch out the crank plug and still the fuel pump does not work looks like i have a few problems. next im going to mess with the computers

BillProctor

ok guys computer was the problem fuel pump now works. i have fuel , fire , compression but it still will not start . we even poured alittle gas down the thottlebody and still not even tries

BuckB91XJ

You may have fuel and spark but, you either don't have enough fuel pressure or your spark is out of time. There is no magic to this. If it's all there and in the correct amount and firing sequence it should start right up.
Check your fuel pressure at the fuel rail test port with a pressure gauge. Turn the key to on and you should have 30 PSI or the pump is bad. If you have 30 PSI then, unplug the vacuum line to the fuel pressure regulator. The gauge should now read 38-39 PSI or your fuel pressure regulator is bad. Check out the Cam Position Sensor inside the distributor under the rotor plate. This gives you your ignition timing function. If it's bad you can have spark all day but, the rig won't run.