Jeep Cherokee Cutting Out Periodically

[Swimmer]

I've had the old '93 Cherokee in to my trusted shop, they replaced the coil, checked the fuel pressure -- its OK. A couple days later she died again (instantly turns off while running down the road-- accessories still working -- will sometimes restart in two seconds on its own or I can restart it in Nuetral while coasting, then eventually it will not restart unless it sits for hours), brought it back to the shop and it wouldn't act up for them. So, I took it back and the same thing happened 30 miles later. Any ideas would be appreciated? Neutral safety switch (my thought, but shop said no)? O2 sensor?

[Swimmer]

Sounds great guys. So maybe the simplest try is to pull the distrubutor slightly and spin the rotor to the opposite postion.? Or just pull the distributor and turn the crank on more revolution and realign the timing marks.?

[upnorth]

I think if you do one more revolution of the crank would be best. I don't rememeber why but just turning the distributor is not a good solution(I could mistaken tho).

[Swimmer]

Update on the Cherokee distrubutor. THinking it may be 180 degrees off, I marked the rotor position, pulled the disrtributor, turned rotor 180 degrees and popped it back in (probly should have listened to upnorth and turned the crank instead). Still nothing, no backfires, or any fires.

SO, went back to square one this afternoon. Pulled #1 plug, put a hose in it, had buddy hold his finger over the hose, found the compression stroke, lined up timing mark w/TDC, visualy checked that piston was in up position, lined up rotor with #1 plug wire -- although it would not set down right on the #1...it was closer to the next plug in line, since the bottom of the distributor has a sort of vane shape and it will only fit in one way or 180# from that way --, screwed down the distrubor...and,....Nothin, no pops even. We did check for spark on #1 and it was there.

Question, do these methods sound reasonable? Why, if I'm on TDC according to the timing marks won't the rotor point exactly at #1? THe battery was getting kind of weak, so put in on the charger tonight (maybe it didn't have enough oumph to fire them?) I hate to admit defeat with something this "simple" , but...

[upnorth]

Was the spark a nice blue spark? If not it may not be enough to fire. Are you sure you are getting gas?

[stmichael]

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Sounds great guys. So maybe the simplest try is to pull the distrubutor slightly and spin the rotor to the opposite postion.? Or just

and realign the timing marks.?

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I am not an expert by any means, but, it almost sounds like his timing chain/belt may have slipped/jumped.

Like I said I am no expert, but, with all that has been tried. Is there an easy way to figure out if this is the case other than taking off the timing cover?

[upnorth]

Very good point!! I am not sure if you can be certain, but not being able to line up TDC with the number one plug sure does sound suspicious. Maybe someone with more experience than this backyard hack will chime in.

[Macgyver55]

Since it ran before changing the distributor I doubt that a timing chain or belt is the problem.

One thought that has crossed my mind, is that with all this cranking and cranking thats been done, the cylinder walls could be washed by unburned fuel causing low compression, and/or the plugs could be fouled by now. Without compression it wont fire whether its timed right or not.

Remember, you need all three...spark, fuel and compression, to make something happen.

When you lose track of the distributor position, the easiest and quickest way to get it right is line up the timing mark and drop the distributor in with the rotor pointing to #1 cylinder.(assuming that #1 is the cylinder they use for setting timing) If its not right at that point then turn it 180 degrees and it should be right.

[Swimmer]

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Was the spark a nice blue spark? If not it may not be enough to fire. Are you sure you are getting gas?

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Thanks again for the replies. No, the spark was whitish orange and kind of weak(?) looking. Yes, some gas was seen exiting the #1 cylinder when we tested for spark. The idea that gas had washed the cylinders, or maybe a weak spark due to battery going may have some validity. I don't know either why the rotor won't line up exactly with #1 plug. According to the Hanes book, TDC should be at "O" on the scale next to the crank sensor.

[Swimmer]

Another update. I talked with the mechanic this morning who fiddled with it a couple weeks ago (and replaced the power coil -- not the pickup coil). He had the answer to why the rotor wasn't lining up w/ #1 at TDC. The fin below the gear drives the oil pump! So you have to pull the dist. out slightly to disengage the gears, but with the fin still engaged...then you can work the oil pump so it allows you to line up with #1. I'll give it a try later today. Man, I hope that's it.

[Jeremy airjer W]

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I don't know either why the rotor won't line up exactly with #1 plug. According to the Hanes book, TDC should be at "O" on the scale next to the crank sensor.

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Good at least we know the new distibutor is working. I agree that between the battery being almost dead and the continuous cranking that the engine is flooded. When you finally do get it started it wouldn't be a bad idea to change the oil (all that unburnt fuel has to go somewhere and its usually in the oil).

As far as the rotor being off a little it should be. The spark occurs before the cylinder reaches TDC. This is timing advance. The timing spec would be 15 - 20 degrees BTDC (before top dead center). When the timing is set, by the time the flyweel has reached TDC the rotor will be past the number 1 post on the cap. All your trying to do is get it close enough to start.

[Swimmer]

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Another update. I talked with the mechanic this morning who fiddled with it a couple weeks ago (and replaced the power coil -- not the pickup coil). He had the answer to why the rotor wasn't lining up w/ #1 at TDC. The fin below the gear drives the oil pump! So you have to pull the dist. out slightly to disengage the gears, but with the fin still engaged...then you can work the oil pump so it allows you to line up with #1. I'll give it a try later today. Man, I hope that's it.

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Nope. It tried to fire once or twice at first, but then nothing. Time to give up and call the tow truck.

[Swimmer]

Another update for those of you helped out and might be curious. The dealer mechanic called and when the Jeep was dropped off, it fired right up! So, the distributor was probably in the correct position all along. Fortunately, they had it hooked up to diagnostics when it killed again. The code said Cam Sensor. So, they replaced that and it died again. The mechanic was intrigued so he put in a couple "free" hours and traced it to a bad wire somewhere in the harness. He jumped it and she has been purring like a kitten. So, lets see...$200 for the power coil, $100 for the distributor, $250 for the Cam sensor, diagnostic labor... Priceless...NOT, but at least the Saga is complete (I hope). And, the dealer mechanic, given that no codes were coming up, said we went about it in the proper way. So, thanks to the guys with the good advice on FM!

[Jeremy airjer W]

The "cam sensor" is what you replaced when you installed the distibutor? Was it the "crank" sensor and/or wiring that was the ultimate fix?

[Swimmer]

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The "cam sensor" is what you replaced when you installed the distibutor? Was it the "crank" sensor and/or wiring that was the ultimate fix?

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The "pickup coil" was in the distributor. The new crank sensor didn't do the trick. Ultimately it was a bad wire shorting somewhere in the harness. The mechanic is putting a jumper wire, circumventing the bad wire, from the computer to the? (I hav'nt picked up the car yet).

[shamalex72]

Swimmer,any problems since it was fixed?

I have a 2001 that is stalling. Its been to the shop and they can't find anything wrong. Do you know which wire was bad?

[Jeremy airjer W]

shamalex72, start your own post filled with all the details including year, make model, engine size and all the details on the problem that you can think of (it happens more when cold, after getting off the freeway, after driving 20 minutes, after a hot soak.

You'd be surprised how much info you can get. At the very least you might get some easy to try ideas!