my '99 cherokee was running fine...started sputtering...couldnt keep it running...gas pedal was doing nothing...it cut off...wont start back..its cranking....have fuel...hear fuel pump...strong stream at fuel rail...have spark...pulled a plug wire and even the coil wire to check...sprayed starting fluid...wont start

 

Test the crankshaft position sensor.

 

How many miles on the motor?

Next step is to ensure that compression is happening. If that is within limits, and if you know for sure that spark is present, and of sufficient quality, then it could imply that the spark is happening at the wrong time (although timing issues typically include some popping/backfiring and attempts to ignite). Timing problems could result from problems with cam pickup sensor, crankshaft position sensor, or the more rare possibility that the timing chain jumped and the cam/crank relationship is now out of synch.

Typically, when the cam/crank sensors fail completely - there is no spark at all (the PCM disables ignition). But if they are not failed completely, but giving the wrong information, the PCM can make bad timing decisions.

It is important that you are confident about your spark and fuel pressure tests before getting too deep. Otherwise you'll waste a lot of time/money and find yourself at square one on those basics.

You might also want to do a system voltage test during startup. Because the XJ can do behaviors like this when the PCM isn't getting enough voltage to do its job. Symptoms for this can include being able to start, but with a strong stumble, with difficulty keeping the motor running without a lot of pedal applied. Which doesn't exactly match your description.

 

the engine is in really great shape...had the compression checked about 3 weeks ago...very even across all cylinders...had fuel pump pressure checked at same time...was having other issues at and went through every ground that could be found...replaced or cleaned grounds at that time...has really ran great up until this happened suddenly..

 

Your description also has the hallmarks of fuel injectors that are not getting commanded to open (pulse). This can happen for a variety of reasons, but one reason is a bad reading from the throttle position sensor (TPS) because if the computer things the throttle is fully depressed while starting - it will disable the fuel injects (sometimes called flood-clear mode). When this type of situation is true it can throw people off because the fuel pressure can be correct, but fuel delivery is still failing. However, you said that starter fluid had no effect. Which if done properly, could rule this possibility out. Was there any reaction at all to the starter fluid?

 

using starter fluid made no difference...not even for a second...still just turning over but not starting...using the search it seems that crankshaft position sensor keeps turning up as likely problem....maybe when my wife falls asleep i can take the one off of her '99 to try...and im joking

 

Don't worry, you can speak freely here. lol. Yes, the CPS can be implicated here. There most common failure mode creates a no-spark situation. Which doesn't match your symptoms. But they can fail in other ways (producing bad signals vs. producing no signal).

Was your spark blue and strong? Because a weak coil can also cause your symptoms. (you have a single ignition coil down on the passenger side of the motor on that year right?)

 

Do you have any engine codes?

 

...no codes...had one for the last 02 after the cat a few months ago...cleared it off...its never come back on...check engine light comes on during cranking so i know that the light still works at least....lol...its going to be tomorrow before i have a chance to work on it...trying to have my mind set on what it could be when i start....just tried to start it 1st time today...nothings changed...except no gas is coming out of the valve in the fuel rail now...i can hear the not that old fuel pump still hum when i turn the switch

 

One other thing to check is the fuse for the ASD (auto shut down). It is fuse #19 in this diagram:https://www.cherokeeforum.com/how-to...diagram-398208 . It is under the hood. I had a problem on my '99 where that fuse kept blowing and shutting down everything. Turned out the alternator was causing the problem. Replaced the alternator and no more blown fuse. This fuse controls power to the injectors. So if it's blown, everything else may look right, but the injectors won't fire.

 

im definitely saving these

 

The ASD relay controls both the ignition and injector circuits. The PCM turns this relay on when it gets a signal from the crank sensor. It also turns the fuel pump relay on. The fuel pump will run just long enough to charge the rail with pressure when you turn on the key, but shuts off after about 2 seconds. I firmly believe the crank sensor has failed or the wiring to it is at fault.

 

So now you have no fuel pressure?

 

correct...last night i tried to start it...just to see if it did anything different...there was no change...except that when i pressed the valve on the rail...i no longer had the strong stream of gas come out....does the exact same thing using starting fluid...just cranks...doesnt start