[Drrm80]

Well about 4 weeks ago i bought a 93 GC with a 4.0 in it for 200$ off a friend who just got another jeep. This jeep ran fine when he had it but hasnt been started since the summer. So i put some gas in it and it start right up for me. I then drove it home and it drove fine. Parked it in my yard and havent touched it since then. I goto start it today and nothing. just keeps cranking. I put a new battery in it, it looks like it has a new coil in it, i put a new rotor and cap in it today, new plug wires. Im gonna put plugs in it tommarow and a fuel filter. But i still dont know why it started then and wont start now, espcially since i havent touched it since then. I turn the Key on and i cant hear the humming....and i poked the valve on the fuel rail and no fuel came out. So im thinking my fuel pump is done. Im gonna see if the pumps getting power tommmarow then im gponna , put 12v manually to the pump and see if it goes on. Anything else i should check? 1 more question is i have a 1992 Cherokee with a 4.0 , can i put that fuel pump into my Grand Cherokee ? or its not the same?

 

[Khaw]

If it was an XJ I'd say the CPS mounted on the rear of the block is bad but not sure the ZJ used that.
Keith

 

[TN-95' ZJ]

Maybe this is just a stupid guess, but I've heard that when a vehicle sits for a while, it gives the gas and everything in it time to settle and when you start it up for the first time in a while, all that gunk will get sucked and clog the fuel pump or somtin in the fuel systerm.......just a thought.

 

[Drrm80]

wouldnt i still hear the pump tho....clogged or not ?

 

[NRV95ZJ]

if you don't get fuel pressure either the pump is bad, or no fuel or bad fuel pressure regulator. check fuses for fuel pump. or its just a bad pump

 

[TN-95' ZJ]

Not real sure......just somtin ive heard that can happen to cars after theyve sat for a while........sry that i cant help ya out more.

 

[NRV95ZJ]

if you don't get fuel pressure either the pump is bad, or no fuel or bad fuel pressure regulator. check fuses for fuel pump. or its just a bad pump

 

[Drrm80]

well i put gas in it, the only fuse i know of is the Fuel Pump relay and its still good....But the pump was working when i drove it to my house and i havent done anything since.....could there be something keepin the fuel pump off....maybe a alarm or somethin...my keyfob is messed up but i just use the door locks to shut it off. Fuel pumps are pretty pricey just trying to find an alternative problem first

 

[Drrm80]

could it be my alarm at all ?>

 

[NRV95ZJ]

if it was the alarm it would start and then shut right back off, go to advanced auto, pick up a fuel pressure gauge kit and test the pressure when you turn on the key, you don't have to try and start it, just turn the key to the "ON" position. if you don't get fuel pressure then you probably have a bad fuel pump. also check the connections at the fuel pump to see if you get power and a good ground when you turn the key on

 

[Drrm80]

well heres the update, i get about 12.v to the coil and the coil had about 1.5 ohms of resistance on the connector side and about 11500 ohms from one side of the connector to the output. but the coil. i tested the Crankshaft Postion sensor and i get infinite ohms. I tested to see how much voltage i get to the pump at the conenctor and its 5.77 volts. i havent sent 12v to the pump yet to see if it works... but im still not getting a spark because i hooked a plug to the wire and held it near a ground and we got no sparkage.

 

[Drrm80]

Sometimes when i hit the valve on the fuel rail fuel will come out, sometimes it doesnt.

 

[Drrm80]

wat i dont get is i drove it hear fine and havent touched it since, get in it and i dont get spark and i dont hear my fuel pump come on.

 

[NRV95ZJ]

its either spark, fuel pressure, or the ecm isn't giving a pulse to the fuel injectors to tell them to put fuel into the combustion chamber.one of the three, don't test the coil, they rarely go bad, take out one of the plugs, test it for spark, get a fuel pressure gauge, test for fuel pressure, the last one you will have to have a special diode that plugs into the injector electrical plug, only a shop would have those unless you want to pay several hundred bucks for a set.
so unless i can't think of something it has to be either spark, fuel, or fuel injector pulse. it would at least run (possibly veryyyyy poorly) if you at least had those three things.

 

[NRV95ZJ]

one last thing, the timing chain could have broke but its VERY unlikely.

 

[Drrm80]

posting on another forum ive come to the concusion it might be a PCM or PCM fuse because No spark , fuel pump wont turn on....and the Check engine light DOESNT even blink once when i turn into the on postion or try to start it

 

[Drrm80]

how can i tell if the PCM is done ?

 

[NRV95ZJ]

put another one in to see if the new one works would be the only way i would know. someone on this forum got all crazy one time and took their's apart to find a whole bunch of water damage. but it took MAD patience.

 

[idrivejunk]

Has anyone looked at the fuel filter i know when i parked mine it clogged the filter in a day or so

 

[Drrm80]

havent changed it yet but that wouldnt cause me not to get spark or power to the fuel pump , i have a new PCM coming today and im gonna try it out.