[Element96x]

Changed fuel pump after no fuel pressureand there was spark and it ran of ether, now there fuel pressure and no spark. Like I don't know what to do now. I'm going to try and change the CPS tomorrow but like I don't understand why i went from no fuel and spark to fuel and no spark. It just crank crank cranks and nothing

[BrunoS]

stop!

check ASD relay under the hood, high power fuse box, passenger side fender above the shock tower. it's identical to a/c relay (same exact part)

swap the a/c relay with the ASD relay.

next, pull trouble codes.

let us know what you find.

fuel injection timing is taken off the distributor sensor on the 4.0. spark timing comes off the CKP On the flywheel.

the ASD controls power to fuel pump if computer does not see crankshaft rotating signal from the CKP sensor on bellhousing. if the relay is old/sticky can cause problems. also check the NSS if you have auto transmission.

CKP is CranKshaft signal pickup bolted to transmission housing.

CPS is CamshaftPositionSensor inside distributor.

[Element96x]

Changed the ASD relay with a known working one and still no luck, I cant pull codes cause i dont have the scan tool. And I just tried starting in neutral and still nothing. just crank

[BrunoS]

ok, borrow a scanner or use the ignition key on/off method to get codes.

next, you need to check to see if you have fuel pressure at the fuel rail (remove valve cap, get rag, press down with screwdriver to see if you have pressure. watch your eyes) and replace cap. do this with engine off, but after having tried to start it for a few seconds. this will test fuel pump. sniff exhaust for gasoline, this will tell you if the CPS and fuel injectors are working.

also, your ignition coil might have gone dead on you. grab a spare spark plug, and plug it into the main coil to the center of distributor cap, have someone crank the motor while you hold the plug to metal ground surface. should spark 6x more than just trying one plug, i like this method the best. should be a nice strong spark. this will check the coil and CKP sensor.

[Element96x]

Problem solved. CPS

[BrunoS]

Originally Posted by Element96x

Problem solved. CPS

ok, just to follow and close this out:

"CPS"

do you mean crankshaft sensor OR camshaft position sensor.

that is, CKP, or CPS.

in future, a tip for checking a dead/almost dead CKP sensor is to disconnect and reconnect the harness connector to the CKP-bellhousing that is next to #6 injector and trying to start it, 1 time out of 3 it might work and get it running. if it died on the trail or road, or wouldn't start, that's a tip that seems to have worked on the forums' xj's as posted.

[Element96x]

crank shaft sensor