hey everyone, looking for some advice as to what i should look at next. I have a 95 Jeep Cherokee I6 automatic transmission and am dealing with a cranks but wont start issue.

It started a couple weeks ago at 4am on my way to work, driving through my neighborhood the jeep randomly stalled and it would crank but wouldnt turn over. got it towed back to the house and the next morning it still wouldnt start and i changed the dist cap, rotor, wires and spark plugs(because they were a month or two out from needing changed anyways) tried to start it, it cranked and cranked and finally turned over. i drove it around the neighborhood, parked it and turned it off. turned the key, fired right back up. so i decided to drive down to oreilly just to check if there were any codes out of curiosity. got 3 miles from my house. and it stalled again in the middle of the intersection. pushed it off to the side of the rode, waited a minutes, turned they key and it fired up again. drove it another 2 miles and it stalled again but i was able to pull into a parking lot. from there i couldnt get it started again. so started diagnosing.

thankfully m dad was able to come give me a hand, we got a fuel pressure regulator and a spark tester. checked the fuel and without the vaccum line connected, we had 39psi as it should be. so fuel was eliminated. started checking spark next. didnt have any spark to any of the wires, so checked the from the ignition coil to center stud on the dist cap, and we had no spark going through it. checked the harness that connect to the ignition coil and was getting 11v to the coil. so we thought the coil was bad. went down and bought a new coil, installed it and still no go. so we next assumed the CPS(which i have changed before and it was not the problem then.) so I looked in my haynes manual and it said to test for infinite resistance of the B and C terminals in the CPS harness and it tested out fine. so i assumed that maybe a wire became exposed and was shorting out somewhere, but i have searched and searched and cannot find any exposed wires. so i am stuck as to what to look at next. i had seen someone mention the ASD relay, so i switched it with another to test it but still no go.

we did manage to get it towed to oreilly and it pulled 5 codes, it pulled 21, 43 twice and 47 twice.

21 is O2 sensor, but would a bad O2 sensor cause a crank but no start and the random stalls? i thought it would still start just run rough.

43 was misfire, which i assumed happened during the stalls and 47 was battery voltage, which i did have to charge the battery due to the battery dying when running the hazards as we were towing it.

another thing i saw people mention was the neutral safety switch, but i dont believe that could be the problem. if it were the nss the jeep would not be cranking at all correct? I am at a loss as to what to look at next, so any advice would be greatly appreciated.

 

The pick up coil in the dist would give those same symptoms as a cps. Try this try to start it. If starts turn it off right away check the resistance then, get a heat gun and point it at metal part of the dist. Make the sensor get hot as if it was running then try to start again if doesn't start check the resistance to see what its doing now.

 

(The NSS will not cause the stalling while driving. A bad CPS is still on the cards.)

1) Did you re-check for spark AFTER installing the new coil?
2) you stated you got a new fuel pressure regulator; but did you verify your fuel pressure in the first place?

 

last time this happened to me it was the pick up coil, the wires had rubbed raw and were shorting out on the block. it doesnt start at all, so should i test the resistance while its cool, heat it up, and then retest resistance?


1) yes i rechecked spark after putting the new coil in and still had no spark from the ignition coil to distributor cap
2) sorry, i meant we got a fuel pressure gauge, not regulator. we checked the fuel pressure on rail and without the vac line connected it was 39psi

 

Where did you get you new CPS from? If it was an aftermarket one I would say that it is more then likely still your problem. If it is an aftermarket CPS return it if you can and get yourself an OEM one. The aftermarket ones are known to be bad right out of the box and if they do work they have a very short lifespan. You can also check you cam shaft position sensor. The one in the distributor.

 

the CPS i had bought from Oreilly it was installed June of 2013. it was a BWD. So despite the CPS testing correctly according to the haynes manual, it could still be the issue? and i didnt test the pickup coil(camshaft) yet, but i will do that next. pretty sure the pickup coil was only like 20 bucks.

 

It is possible that it reads good and it still be bad. When mine went bad on my 98 it tested good but in fact it was still bad. I replaced it and never had a problem with it since.

 

I thought that may be the case but didnt really want to switch it out if it wasnt that. so i guess i will test the pick up coil first and if that isnt it ill replace the cps and go from there. Thanks!

 

No Problem. Just keep us updated.
Good Luck.

 

I had the same issue...
Starts sometimes, doesn't sometimes, never stalls, but sporadically won't start, warm or cool, dry or wet...
No rhyme or reason...

>> old man's trick... have someone crank it when it's in a "no-start" mood. Put on rubber gloves and cover them with leather ones. Start wiggling wires and connections in the engine compartment.

KEEP YOUR HAND CLEAR OF MOVING PARTS!

And be sure to wear gloves, shorted wires can zap you.

My jeep sat 2 years in a field...

I replaced the coil, wires, cap, plugs, cps, etc, etc...
Enough to buy a new jeep probably...

Wouldn't start. Turned it over and wiggled the wires TO the coil and it started right up. It was even repeatable. I had clean new connections, had to pull and replace 1 little wire.

The second time it was the wiring harness on the firewall. In the plastic safetly cover, they had worn down and shorted. Couldn't find the problem with a voltometer, but found it... "jiggling."

Plus, it doesn't cost anything to spend 1/2 hour cranking and jiggling.

Good luck. Have fun.
Billy

 

Also...
No one mentioned...

Clean your grounds!

Cheap and easy, never hurts.

 

If you can get the pick up coil for 20 bucks, get it and eliminate that from the list. Just went thru the crank but no start with my 99, turned out to be the cam sensor(pick up coil assy. or who ever your getting it from calls it.) Went thru all the suggested answers that were given in my thread, clean this check that. For 20 bucks I would jump on that, mine cost me 58 with my discount. When I replaced it fired right up like nothing was ever wrong. The other good thing that can out of this, besides the knowledge bestowed on me by the kind folks here, was found out a bearing was going out in my distributor.

 

Remove neg battery cable for 15 minutes or so . Hook cable back up and try to start then recheck codes with key on key off method by counting light flashes.....http://jeep-xj.info/HowtoECUcodes.htm