foxrider4lyfe

ok so i just picked up an 88 xj owned by an old man for woods truck,motor was fully rebuilt but the water pump started leaking so he parked it for a year, 500 bucks later and its mine

when key is on the fuel pump is not engaging i dont know if its the relay or pump but it turns over and fine and will run off a few shots of ether

any advice to getting this ole jeep running is much appreciated
thanks

89Laredo

Ballast resistor? I dont think that is used with the key turned on, but its worth a shot. Its the ceramic piece held in with one bolt on the drivers side fender under the hood. Take the two wires off and splice them together.

trans_am7935

if not the fuel pump, then i would check the crankshaft position sensor on the driverside top of the transmission, they are known to go out for no reason at all

89Laredo

If you read what the OP says you would see that he mentions:
Key on--fuel pump not engaging---"will run off a few shots of ether"

Therefore, the CPS is not bad, since it is firing the spark at the correct times. This also rules out the "Sync Sensor" located in the distributor.

It is something in the Fuel Pump circuit. Relay, Fuse, Bad Ground, Short, ETC.

foxrider4lyfe

well the old man said is was getting no spark last week so he bought a new coil pack,but as of now since the fuel pump is not engaging is there a way i can hardwire it to a battery or something just to test? if so how would i go about checking that

89Laredo

I think you can run power across the relay slot, Im not sure what pins though... Ill try to find something.

89Laredo

Fuel pump relay:

Use a small piece of large gauge wire to jump pins 30 and 87 in the relay socket, this will cause the fuel pump to run

foxrider4lyfe

okay thanks will check tomo and get back with the results

Bustedback

If it sat for a year, I would say the fuel pump is seized because of condensation and the crappy fuel that we're forced to burn these days causing the gear rotor fuel pump to rust and corrode.

tampaviking

Could be a loose wire on the fuel pump, I would also check the wires from the pump at the pump and work forward.

foxrider4lyfe

this is what i was thinking

swnp101

You can't hear the fuel pump when you turn the key? Maybe it's just my jeep; but I can hear it prime before I crank.

And before you get all fancy shorting ****, how about just testing the fuel pressure at the rail when the key is turned on? And, if you're worried about the relay, switch it out with a known good (ie, A/C relay). But I've said this a million times and people never really hear it... RELAYS RARELY GO BAD OUTSIDE BEING PHYSICALLY BROKEN/DAMAGED.

[Edit: Ok... just to cover my ***... Yes, it is possible for a relay to go out. But it's very easy to check. Takes 5 seconds to swap it with a known good one.]

foxrider4lyfe

the fact that i cant hear my fuel pump means its not working, when the key hits the on position it can be heard priming.
in this case mine doesnt which is why im thinking the pump is bad since its been sitting,unless a wire is bad

swnp101

Again, just to confirm our suspicions, check the fuel pressure at the rail. If theres no life there, lift the rear, unplug the fuel pump connector and check for voltage with a multi-meter. If voltage is good there, then it's the pump, nobody home, then look for an electrical problem.

foxrider4lyfe

what should the pressure off the rail be