Xj problem

bigtruck

Registered User
Location
lehi
I have a 90 xj that wont start. Its the 4.0 and I can hear the fuel pump kick on and it will turn over but it wont start. Any help would be apriciated thanks.
 

Badger

I am the Brute squad
Location
South Salt Lake
CPS sensor would be my first guess.look along the fuel rail at the end by the firewall you'll find a wire loom that has a plug witha wire that trails off down to the trans bell housing were you will see a sensor bolted to the bell housing.

unplug the sensor up by the fuel rail.to the car to on do not start just turn it to on.turn it back to off and plug it in.if it still doesn't start do it agin but leave the key to the on position.when you plug the sensor back in you should hear a relay clickover on the passenger side.if you hear this lite click it should turn over.this works for me when mine has issues.but really you should replace the sensor if this is wha tthe problem is.
 

Milner

formerly "rckcrlr"
Badger said:
CPS sensor would be my first guess.look along the fuel rail at the end by the firewall you'll find a wire loom that has a plug witha wire that trails off down to the trans bell housing were you will see a sensor bolted to the bell housing.

unplug the sensor up by the fuel rail.to the car to on do not start just turn it to on.turn it back to off and plug it in.if it still doesn't start do it agin but leave the key to the on position.when you plug the sensor back in you should hear a relay clickover on the passenger side.if you hear this lite click it should turn over.this works for me when mine has issues.but really you should replace the sensor if this is wha tthe problem is.

Yep, had the problem MANY times. Sometimes just the plug is bad, other times it is the sensor....
To change the CPS, it is one the bell housing about 10 or 11 a clock if you are looking at it from the rear (drivers side of motor). It is held in with 2 small bolts. I found it easiest to use about 3 Ft of extensions and a wobble socket and feed it in from behind the tcase....you can get a pretty straight shoot at the bolts that way....

NEVER, EVER use an aftermarket CPS. I have had 5 bad ones in a row from AZ and PepBoys!!!!!!!!!!! GET THE FACTORY JEEP ONE :D
 

bigtruck

Registered User
Location
lehi
What harness? I am new to the jeep thing and am not really sure what you are talking about. Thanks Badger
 

Milner

formerly "rckcrlr"
Badger said:
really because i have been running a AZ cps for awhile now

Yep, IIRC MBryson had similar issues with the non-factory ones. I have heard it from others too. I got to the point that I carried a spare with me....Get a factory spare as a backup....$30 cps is cheaper than a tow ;)

Ironically, I carry a spare CPS for my PSD too....
 

Hickey

Burn-barrel enthusiast
Supporting Member
way2nosty said:
second guess is fuel pressure regulator - check static fuel pressure at the manifold.
XJ Fuel pressure Regulators are pretty reliable. I have never even heard of anyone having a problem with one. Replacing one is spendy. XJ fuel problems are usually the pump or pump relay.
 

way2nosty

Registered User
I've seen plenty of them, with the exhaust and intake on the same side of the motor the heat tends to do them in.
 
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