JustDHutch

Hi all. I use to have a 93 wrangler, and now I just picked up a 92 Cherokee 4.0l Auto with 156k miles. I've always used forums to solve my problems on my vehicles and i've searched for this problem and done most things people suggest and still no luck.

Heres my problem - The Jeep starts and immediately dies. If i give it throttle it still dies. Sometimes when I give it throttle it will rev quick before dieing. It only stays running for about 1 second and rarely stays running for up to 3 seconds. Here's what i have checked.

1.Crank position sensor (installed new one, no help, put old one back in)
2.Throttle Position Sensor (Installed new one, no help, old one back on)
3.IAC (removed and cleaned)
4.MAP Sensor (Unplugged to run on default mode)
5.Checked the 6 pin relay under passenger side dash
6.Checked the resistor on the drivers side fender by twisting the wires together to bypass the relay/resistor (whatever it is)
7.Checked fuel pressure. It reads 32psi with the key turned to the on position. when i start it, it quickly jumps to 42psi, then when the motor dies, it returns to 32psi.
8.I read somewhere the cat gets plugged so I split the exhaust before the cat but no help.
9.New Cap, rotor, plugs, wires.
10.Swapped Fuel Pump Ballast Resistor from running Jeep
11.Fuel pump relay, tried 2 others.
12. WILL STAY RUNNING ON STARTER FLUID
13. Brand new fuel pump
14. Fuel Regulator doesn't leak
Anyone else have any ideas? I'm pretty lost on this.

Long Island XJ

inspect and clean cap and rotor.

JustDHutch

Thanks for the input Long Island XJ. I just installed New Cap, rotor, plugs, and wires...No help. Any input is appreciated.

jeepxj412

ok sounds weird but i had the same problem and i couldnt think of what it could be and then my friend (standing next to me with the hood up) said hey look at your battery terminals, they're corroded. so i cleaned them up good and started right up. the only difference between your problem and mine is i was able to rev it up and keep it running. but hey its worth a shot looking right?

Long Island XJ

haha yup looks like that was the ninth thing you did

saleen9973

Does it have a factory alarm? If so unlock the passenger door and then try to start it.

JustDHutch

It does not have an alarm system. But I tried it anyways. Unlocked both driver and passenger doors a few times with the key.

I've been reading that alot of times its the Fuel Pump Ballast Resistor. I included a pic at the bottom from another post. I measured the resistance and its 1.5ohms (setting was on 200). Can someone else measure the resistance on theres please so I can see if its bad?

JustDHutch

UPDATE - I sprayed some carb cleaner in the intake, and it ran for about 10 seconds which is the longest it has ran so far. So this tells me is must be a fuel related problem.

Either the pump isnt sending enough fuel after the start, or something is telling it to not send fuel after the start.

658 Bucks

That does not make sense though, because your fuel pressure guage is reading 42 psi. It sounds like a cap honestly.

Could your fuel filter be clogged?

JustDHutch

True but it only hits that for a split second then right back to 32. Once the Jeep is running doesnt the ballast resistor kick the fuel pressure down?

Previous owner said that he replaced the fuel filter and problems started after he put a new stereo in. I crawled underneath and the fuel filter looks brand new so I believe him on that.

658 Bucks

Yeah I do not know the specific numbers, but I think that once the engine is on the pressure falls. 32 sounds about right, but the 42 seems a little low. I know that it is contray to reason, but when the engine is off the fuel pressure should be more, I think like in the 60s. I could be wrong, but for some reason that is what I am remembering. Dont quote me on that, because I am not for sure.

JustDHutch

Yeah thats also what i've read. My Haynes Manual says 31psi when running and 39psi when you remove a vacuum from I think the fuel regulator. It doesnt say anything about when its off though, and since it wont stay running...

JustDHutch

Ok took a ballast resistor out of a friends running jeep and it didn't help. I'm gonna try to spray gas or starter fluid in it later to try and keep it running long enough to see what the fuel pressure does. Any other ideas?

658 Bucks

Did you find out the pressure when off? I have been thinking about this all night and can't think of anything else. I was going to suggest the map sensor, but you already did that. What about computer? I doubt that this is the issue, but at this point I would try everything. I forget, did you try the TPS?

I dont know how the 92 is different, but you might go ahead and try a new fuel pump, it is a pain in the ***, but might be worth it.

captainwoot

you have checked fuel pressure, but have you checked flow? you can have pressure but no flow..... possible fuel pump? or not enought current flow at the pump , green fuzzy wiring? fuel pump relay, asd relay?
good luck !