tburk

Well, ive owned jeeps for over 12 years now (on third one) and have not had any problems that I couldnt overcome thus far. This morning I got up for work and the thing wouldnt start. Its a 98 Cherokee 4.0L with 161K on it. Read up a little today on various things and at first I suspected the CPS. I checked it with a meter and pin B to C read open, from the Haynes manual it should. So I pulled a plug and verified I had spark. I took off the fuel rail pressure cap and when I pushed it in some fuel came out but not that much. I turned on the key to the run postion and no serious pressure or fuel escaped. I swapped out the fuel relay with another one of the same type and still not PSI. I then cranked it over about 5-7 seperate times and pulled two plugs and neither of them had much fuel on them. I would have expected them to be douched with gas. So the dreaded question....fuel pump right? I did check fuse 21 in the PDC and it was ok.

Any thoughts?

Thanks,
Todd

bobvalli

Well that sux

When you turned the key, did you hear the pump kick on?

ezab

I would check injector pulse before saying it is the fuel pump for sure but it definitely sounds like a bad pump.

longship

My mistake, didn't read OP properly.

Rob

tburk

Im not sure that Ive ever noticed the pump kick on, guess Ive always overlooked it in the past...If the pump was running, wouldnt i have fuel gushing out of the rail when I depressed the valve stem?

Thanks,
Todd

bobvalli

Maybe check for voltage near the tank with a VOM?

That way you know the pumps getting power.

tburk

Anyone know the pin out information for the connector that plugs into the fuel pump so I can verfiy the voltage there? My haynes manual is somewhat lacking in the schematic realm.

Thanks everyone for the reply's!

Todd

bobvalli

It looks like it'll be the connector with the dark green/white and black wires.

DG/WH comes from the relay and black is ground.

You might want to check fuse 11 (says located in junction block) and fuse 22 in the PDC

Maybe rather than a VOM a test light would be a better choice.

mayko

hey i have the same car 98 cherokee 4.0 4x4 and it did the same thing. it would not start. i tryed to jump it and nothing again. i put the car in N and then bam started right up. it might be the neutral safty switch. it was the first time this happend to me.

tburk

Bobvalli, by junction block..I presume that to be the fuse panel on the pass. side just in front of the door? As soon as my wife gets back and can watch my baby i'll get back in the garage to verify these recent suggestions.

Todd

bobvalli

Good call mayko
Easiest things first.

tburk - try putting it in neutral and see if it starts

tburk

Well fuse 11 and 22 check out fine. When I have the thing in park it'll turn over, when I put it in N it does not - so that rules out the N switch. I didnt get back underneath to verify voltage at the pump as my wife is with the baby and I dont have her help anymore. I'll try more tomorrow.

Why do my cars always need me to work on them when its cold?

Thanks All,
Todd

tburk

Checked the voltage at the plug that feeds the fuel pump and sending unit. Have 5 volts on the wires for the fuel level sensor but 0 volts on the wires for the pump. Backtracked and reverified the fuses (21 in PDB) and fuse is good. Only me here today so I couldnt check the relay snapping when turning key on. 10 bucks at NAPA swapped it in.......still no pump voltage. Checked the wire for short to ground and its not shorted. Haynes manual has very basic schematic....time to do research to draw out the ckt to check for opens (I cant figure out what else it could be?)

Thoughts?

Thanks

Todd

ezab

Ballast Resistor?

Edit: Never mind doesn't have one.

ezab

Check Fuse 11 in your Junction Block.