My 1999 jeep cherokee stalled out the other day, didnt make any noise, and now wont start back up. I tried the ASD relay, crankshaft sensor, plugs, distributor cap and rotor. Im getting spark, compression, and gas, so i have no idea what could be wrong...It cranks but wont run, tried starting fluid in the throttle body.

which engine? (asked now 1000 times, only 2 ever answered)

tune up time, spark parts, rotor to plugs. filters. both.

its called a 60k mile tune up solves most.

my guess, is its misfiring or

is this the ASD relay dropping out then back in, as driven.

jerked before and after CKP sensor, did you know its the last thing to fail......

see the list of ASD drops.

misfiring, can be felt, its like a misfiring chain saw, ever here a 2 stoke misfire, ratta, tata ,tat?

some call it jerking, its not, is misfiring. (3reasons ) and 25 causes.

but jerkin real, like if you cut the ignition that is and instant bog.

but if you off the key and back on , fast, that be a jerk

that is total power loss. not misfire. its loss spark and fuel.

and jerks hard.

so does loss of 12vdc to the EFI system.

so the first step is to see if its the ASD relay dropping out.

on all jeeps.. 93 to now.



ASD



http://www.fixkick.com/Jeeps/ASD.html



automatic, shut down. (relay and EFI logic)



key point, the ASD will kill the engine, if fit sees spark is bad.

so its a chicken and egg deal.

here is the logic.

key on , crank , ASD closes, fuel injects and engine starts

then dies in seconds. or runs full time.

note that if the ECU sees spark dead, it cuts spark.

Sounds odd , huh. but is NOT.

this relay stops all car fires. (caused by this protection not in place)

Crankshaft sensor is responsible for fire (located driver side behind the engine mounted to transmission bellhousing), camshaft sensor (or distributor pickup) is responsible for injector pulses. Also check the ASD relay underhood and switch it with another like the horn relay.

If you can hear the pump running inside the tank right after it stalls and you turn the key to the run position, I'd be looking at the crank position sensor. If that fails, fuel will reach the fuel rail but the injectors won't fire. Also check cam sensor, pump relay and ASD relay in power distribution center.

Found that the outboard PCM cover screw was shorting out the circuit board. Chrysler PCM p/n P56028412, s/n TEH106636023.

Short story long: I have a 96 Grand Cherokee 4.0L, 125,000 miles. Several weeks ago, I started to have stalling issues. Hot or cold, dry or wet, first drive of the day or last, it didnt matter. The engine would cut out. It felt like it lost all electricals.
At the time it was showing an ASD relay code. Swapped the ASD and A/C relays. Same problem. I didnt have time to look at it, so I had the dealer go through it. After 2 days and $200, they called and said it was the ASD relay, and that they put in a new one, and its all good. Um, ok, maybe I missed something. Im a trusting soul, but lets see if this fixes it. The next day the problem was back. I went back to the dealer and they basically said, We dont know what it could be, good luck with that. Now my wife knows why I dont go to the dealer. By the way, the old relay tested good.
My turn. Being the methodical aircraft mechanic that I am, I grabbed a multi-meter, contact cleaner, and wiring diagrams. I cleaned connectors, ohmed out wires and sensors, checked for power and grounds. Everything checked good. By now, its showing ASD, crank sensor, and primary ignition codes. Then, with my wife trying to start it, I wiggled the connectors on the PCM. Every time I wiggled the gray C3 connector just right it would run. When I let go, it would die. So I took the connectors apart and tightened up the crimps (I dont recommend doing this without the proper extractors and crimper). Threw it back together and BAM! Same problem. Well, time to bite the bullet and check for bad solder joints on the PCM board. I took the cover off of the PCM and realized that looking through the potting compound is like looking through Guinness Stout. But, I put it back in and hooked it up. It started stronger than ever, and didnt even think about stalling. Yes! I figured that I finally got the connectors sorted out, so I left it over night to cool down. Got up the next morning and it started right up and wouldnt stall even when wiggling the connectors. So I put the cover back on, put the PCM back in, hooked up the connectors, and BAM! It wouldnt start! That was the point when my wife asked, Hows it going? And I, being the methodical aircraft mechanic that I am, said, what the ----? Thats when my wife turned around and went back into the house. While smoking a pack of cigarettes, I thought, Gee, it runs with the cover off, but not with it on. DUH, wonder what it could be? So I backed out the two screws that hold the cover on and BAM! It started right up. Then, while it was running, I tightened the outboard screw and sure enough, it died. Yes! Aircraft mechanics love it when they can make things stop working. I installed new screws (1/4 long, factory screws are 1/2 long Torx head), and shes been running great ever since

CHECK ASD RELAY THAT IS AUTOMATIC SHUTDOWN RELAY IN THE POWER DISTRIBUTION CENTER UNDER THE HOOD IN ENGINE COMPARTMENT.IF ASD RELAY GOOD PROBLEM COULD BE CAMSHAFT SENSOR IN THE DISTRIBUTOR.TO SAVE TIME AND MONEY HAVE JEEP SCANNED FOR CAMSHAFT SENSOR AND CRANKSHAFT SENSOR FAULTS.

If computer sees no crank sensor signal it shuts down pulses to the injectors. But, you bring something new into the mix. Make sure fender grounding is good so the relay can operate properly and make sure power going to it is not restricted by a loose or dirty contact on the power side.

you have to hook up a fuel pressure gauge while its runnung to rule out the fuel pump and check for codes also. This is just the start in getting it diagnosed. You also have an ASD Relay that can cause this as well as a fuel pump relay and also a crank sensor.

Check the asd relay in the fuse block. Replace it with a known good relay

I Found that the outboard PCM cover screw was shorting out the circuit board.
Short story long: I have a 96 Grand Cherokee 4.0L, 125,000 miles. Several weeks ago, I started to have stalling issues. Hot or cold, dry or wet, first drive of the day or last, it didnt matter. The engine would cut out. It felt like it lost all electricals.
At the time it was showing an ASD relay code. Swapped the ASD and A/C relays. Same problem. I didnt have time to look at it, so I had the dealer go through it. After 2 days and $200, they called and said it was the ASD relay, and that they put in a new one, and its all good. Um, ok, maybe I missed something. Im a trusting soul, but lets see if this fixes it. The next day the problem was back. I went back to the dealer and they basically said, We dont know what it could be, good luck with that. Now my wife knows why I dont go to the dealer. By the way, the old relay tested good.
My turn. Being the methodical aircraft mechanic that I am, I grabbed a multi-meter, contact cleaner, and wiring diagrams. I cleaned connectors, ohmed out wires and sensors, checked for power and grounds. Everything checked good. By now, its showing ASD, crank sensor, and primary ignition codes. Then, with my wife trying to start it, I wiggled the connectors on the PCM. Every time I wiggled the gray C3 connector just right it would run. When I let go, it would die. So I took the connectors apart and tightened up the crimps (I dont recommend doing this without the proper extractors and crimper). Threw it back together and BAM! Same problem. Well, time to bite the bullet and check for bad solder joints on the PCM board. I took the cover off of the PCM and realized that looking through the potting compound is like looking through Guinness Stout. But, I put it back in and hooked it up. It started stronger than ever, and didnt even think about stalling. Yes! I figured that I finally got the connectors sorted out, so I left it over night to cool down. Got up the next morning and it started right up and wouldnt stall even when wiggling the connectors. So I put the cover back on, put the PCM back in, hooked up the connectors, and BAM! It wouldnt start! That was the point when my wife asked, Hows it going? And I, being the methodical aircraft mechanic that I am, said, what the ----? Thats when my wife turned around and went back into the house. While smoking a pack of cigarettes, I thought, Gee, it runs with the cover off, but not with it on. DUH, wonder what it could be? So I backed out the two screws that hold the cover on and BAM! It started right up. Then, while it was running, I tightened the outboard screw and sure enough, it died. Yes! Aircraft mechanics love it when they can make things stop working. I cut the screws (1/4 long, factory screws are 1/2 long Torx head) with a pair of wire cutters, and shes been running great ever since.

Since you've replaced many of the usual suspects (fuel pump etc.) you might want to look into testing or simply replacing the crankshaft position sensor or the camshaft position sensor. If you intermittently lose one the these signals it would cause the problem you describe.