2000 Cherokee 4.0 .driving went dead. Got towed to the house. Next day the coil pack had white filling coming out. So new coil pack, Im here so new plugs. Spins over no start , no codes, now new crank sensor, spins over no start. Ok new ECM plug an play to the vin of vehicle. Spins no start no codes.
Well maybe bad crank sensor being it was BWD. Now new Echlin crank sensor. Spins no start no codes. I had checked fuel pump pressure at start of this. 50 lbs or there about
All fuses are good . Any input would be gratefull

 

Welcome, tramp.


Are you ready to start testing your way to a solution? Or do you want a list of parts to throw at it? We aren't much in favor of firing the parts cannon, but we can help you with the diagnosis part.

For starters (heh. get it? STARTers? ), have you checked to see if you have spark? Sounds basic, but that's where you need to start. I'm guessing you don't, but that guessing business can get expensive. Let's try testing instead.

Also, check your ASD relay. It's in the PDC, over by the battery. There are a few relays in there that will swap around. I don't recall which one is the ASD, but you can just play a shell game with them and see if you get anywhere.


By the way, sensors on these beasts are very picky. There are usually one or two horror stories every week where someone bought an aftermarket sensor (like Echlin) and it was bad out of the box, or it failed in a few minutes, days, weeks, or months. Spend the coin on Mopar sensors. You will be glad you did. The most touchy one is the crank position sensor, followed by the cam sensor.

 

^^^^^^^ What Mark said.

Testing spark on a 2000, due to that whole coil pack thing, can be "interesting". It may be worth it to find a good tool rather than dealing with the rigging up that I've seen some folks do.

I'd be looking at your CPS wiring and the coil pack wiring. As I understand, the coil pack wires can chafe in the back and if the wiring isn't good, you can't even begin to think about whether the sensor that it's connected to is bad or not.

 

Also check the grounds. I had a 1991 Cherokee that would run fine, but at times (usually when it was not convenient) just die. Wouldn't restart (can't remember if it would turn over), after about 30 seconds it would eventually start. Would run fine for a week before same problem popped up. I removed the ground strap from side of engine block, cleaned it all up, reattached it tightly. Never had the problem again. A long shot, but still worth checking out.

 

Moved the relays , no help , did that 2nd day . There were no bad wires at the coil.
I will be checking grounds,
Thanks for input. Im ready to fix this thing. its my ol ladys , she runs mail with it

 

I don't know if this helps you at all, but the plug on the coil rail has 4 terminals. one is 12v when the ASD relay is activated, and the other 3 are grounds to the PCM for the coils inside the rail. This engine uses the "waste spark" system in which 2 plugs fire together, one on compression and one on exhaust, every revolution of the crank. They fire in pairs, 1&6, 5&2, 3&4 in that order. The grounds go to digital drivers in the PCM and the ground circuit is interrupted to fire a spark.

It sounds like there was an internal short in the coil rail that toasted your PCM. You've already replaced both of them, so try this. Disconnect both battery cables and clamp them together, thus draining the memory from the PCM. Charge the battery completely until it holds at least 12.5 volts. Reconnect the cables to the battery, turn the key on and wait until the warning lights go out, then crank it. Let us know what happens.

BTW, do you have the Security Key System? It was optional with the 2000 models

 

I will try the battery thing as soon as daylight. Thanks for input . It just has regular keys Thanks again. Will let you know what happens

 

Had cables jumped together , while charging the battery. Hooked back up, waited for dash panel to do its thing. Still crank no start, no codes.🙄
Any other suggestions..?

 

Thanks Dave , I believe it was

 

Well after everthing said an done. I went back an checked. , no fire out of coil pack..

 

If the dash warning lights went out, you obviously have communication with the PCM so the problem lies elsewhere. Does it fire if you spray brake cleaner into the throttle body? If it does, you've got spark. That also would mean the ASD relay is pulling in. Which also means you're getting a crank sensor signal. See how the diagnostic chain works? If you've got spark, the problem is with fuel delivery, either no pressure or no injector signals. Power for the injectors comes from the ASD relay and are signaled to fire by drivers in the PCM grounding them.

If no spark, the whole thing reverts back to the ASD relay not pulling in. The most common cause of that is no crank sensor signal or a blown fuse supplying it. Pull the relay and check for 12v on one of the big crosswise slots. The socket has 3 slots that run lengthwise and are smaller and 2 that are crosswise and are heavier. The heavier ones are the power out terminals. The smaller ones are for the holding coil magnet. I think 2 are for the magnet itself and the third one is a feedback sensing wire. You can jumper the 2 big ones and see if it will fire, as long as you have 12v in one of them. It may not run because of the lack of crank signal, but you can "prove" the ignition and injectors as functional. If it does run, that proves you have a crank sensor signal because it pulled in the fuel pump relay.

That's enough for now to keep you occupied. Let me know what you find out.

 

Ia appreciate your input, but I have 50 lbs pressure on fuel rail. Sprayed carb cleaner to no avial A second ( elchin this time) crank sensor, . I jumped ADS like you said still notta...

 

Maybe you can answer a question on the crank sensor bolts. One has a shoulder , the other one doesn't. I didn't notice when I took them out, but does the shoulder one go into a specific hole to position the sensor correctly ?

 

Not sure about the bolt, but I'd be checking the wiring to the crank sensor and the cam sensor.

BTW, the cam sensor will give very similar symptoms.

 

Ran a scan Snap On Scanner..Ethos, it shows the Jeep should be running.
It has a new cam sensor
Checked wiring from ECM
to coil all wires have continuity .
.. .50 lbs fuel pressure, good gas.. At a total loss
Thanks for input.
Will keep ya'll informed