hello everyone I have 2 2000 jeep cherokees, White Jeep cranks but does not start. Since I have 2 of these cars I decided to switch the crank position sensor and coil bar from the two cars. Blue jeep still runs and White jeep is still dead. I also checked that i have fuel to the bar and replaced the spark plugs.

the only code that fires is p0140 - o2 sensor rear bank but that code has been firing for a month or so and to this point has not had an impact. I occasionally get a NO BUS reading but that has been going on for about 5 years and has never had any effect on the car and can be remedied with a tap to the area under the steering column.

any help on a good course of action would be appreciated.

 

Im going thru the same thing right now... Ive changed crank. cam and presently waiting on a coil. I youtube searched a bunch of tests. www.fixjeeps.com had some quick checks. Btw I see your in Akron.. Canton here. Ill be watching your posts for my own selfish reasons... Good luck

 

coreyt,

A no crank problem is pretty easy to suggest things over the web. A crank-no-start condition is a little more difficult. Because it could be fuel, air, spark, timing (ignition), timing (cam/crank), exhaust, or compression that are causing the problem.

From the sounds of your post, it would seem that you are not seeing spark, but I'm just guessing by the types of components you said you already swapped.

The good news is that each of the areas I mentioned can be ruled-in/ruled-out if tested properly. But that is key, for example testing for fuel in the rail vs. actually testing fuel pressure at startup are quite different, and the first is not sufficient to rule out a fuel delivery problem.

Here is a video covering some of the methods for working through those areas and getting a solid direction to follow. Its worth your time.

 

did you check all of the fuses?

 

Does it start even briefly using starting fluid?

 

good luck to my canton friend, its been cold the last few days, not fun for working on cars. to answer the questions so far, the car doesnt trart with starter fluid, I tested all the fuses in both the engine compartment and passenger side, and no I dont get spark. the car ran fine for a quick drive to the store and when i came out it wouldnt start.

 

this is exactly why i wont consider taking a trip in my great running 2000. they call me a "worry wort" but what can i expect. theres a dozen things that can do just what yours did!!
i drive 8 miles to town to shop and wonder if ill get home!!
love the ride but dont trust it...

 

Start at the ASD relay in the PDC. Either it is being commanded to close by the PDC during the startup, or it isn't. If it is, then you can move towards the ignition side, and if it is never being commanded to close, then you can move towards the computer side. If the computer is good, then that will likely lead to a sensor that has failed or is having connectivity issues.

Another route, given the symptoms, is to start back at the CPS. Its one thing to swap it with a known-good, but that won't help if the problem isn't the sensor itself, but the connectivity to the sensor. Has that all been tested yet? Normally, you'd expect some codes if these sensors weren't being sensed by the computer, but with your no-bus condition it makes me wonder if that can be trusted. Also, was your knowledge of the codes you mentioned recent? or was it based on some scans from the past?

 

Pull the coil plug and check the green stripe wire for power when key is turned to on.. You should hear the ASD relay kick in also.. Crank engine check green stripped wire while cranking for 5 seconds this will confirm your crank sensor is doing it's job ( from what I have read)

 

ok i checked the ASD relay by simply switching it out the relay itself is good. is there a better way to check this? also i checked for power at the coil clip, i do get power to the coils on crank.

 

I tested for power at the green wire, I got no power to the wire with the key in on position but i do get power to the wire on crank and then i see and hear the ASD relay click and loose power when i stop cranking over. can you confirm this is what i should see.

 

Well i figured out my issue with the crank no start no spark. after a considerable of advanced electrical diagnostics (if you are having an electrical issue i highly recommend getting your hands on the original wiring diagrams) we found that we had a faulty cam position sensor and synchronizer gear. basically what happens in the 2000+ pjs is there is a the bottom half of a distributer which spins as the engine cranks over, a small electromagnetic field senses the turning of the distributor and supplies signal to the computer. in my case the physical synchronizer gear housing broke sending bits of metal spinning around breaking the sensor gear and shorting out the computer.

after replacing the synchronizer gear and sensor i got a condition of start and immediate kill. working on a hunch (and having already checked many other parts in the ignition system) i bought a used computer (same year and exact same model number 635ag) which was a plug and play fix.

 

The occasional "NO BUS" signal on the dash it problubly due to a loose wire coming from the CPM hope this help!