Hey i just picked up a 1994 4.0 xj that has been sitting fo a few years. I switched out the gas tank and fuel pump. The problem is iam not getting any spark or fuel, any ideals? Could it be a cps? I did check all the fuses also. Thanks for any help. Mike

 

Prolly CPS quick way to test the connectivity is to unplug and then repplug it back in. Connection gets degraded over time and will not send a good signal. Try that before you start trying to replace it. Canned air also works great to clean it out!

 

mine sat over night and a mouse had fun try a cps, the first time is a pain in the butt

 

Try the auto shutdown relay, or perhaps the ignition switch. Do you have power to the coil tower with the key on?

Put your hand on the auto-shut down relay (pass side fender), and have someone turn on the key. If you feel it click, it's good.

I'm almost positive that the key switch energizes the auto-shutdown relay, which sends power to the ECM, then the ECM energizes the fuel pump relay. The computer sees the pick up/ CPS NOT spinning, and kills current to the pump relay.

You'll **** off that guy you bought it from if you tell him it was a 15 dollar relay!

Please report back on your findings.

 

Okay check that; I just pulled my shut-down relay, and my fuel pump still came on- it just didn't fire.

If you don't have fuel pressure AND you don't have fire- you've got an electrical problem, not a sensor problem. First diagnose why your pump isn't working. Maybe now I'm going back to the key switch again.

Although I doubt it- could be the computer; they do go out.

 

I would go with CPS also, can you hear your fuel pump prime at all.

 

He says he isnt getting any fuel... Did you verify with a guage or are you just assuming your not getting any fuel... Hmm cause if you are not getting fuel I am going with the fuel pump also. Put if you have fuel and spark but its not firing then I go with CPS.

 

I have checked the fuel pressure at the fuel rail,you can not hear the pump also. The relay does click.

 

Probe the wire with a test light at the pump pigtail. You said you put in a new pump, right? That's weird that its not working even though its new.

You feel the fuel pump relay click, or the auto shutdown relay click? Don't listen for it, you need to feel it.

 

haha i know this is simple but you getting 12.6V from the battery?

 

It was a used pump and tank from a rolled jeep. The jeep iam working on has not been started since summer. At Least thats what the guy said. After seeing the tank and pump i have my doubts. The inspection went dead in 05.

 

I swapped a pump before and somehow I knocked off one of the wires when I was putting it in. But that doesn't really help the no spark.

 

this why i changed the pump and tank

 

i believe the orange wire out back is ur hot 12v to the fuel pump my friend had this happen randomly

 

it was the ecm thanks guys