random stalling.. another CPS?
07-01-2011, 02:10 PM
#1
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random stalling.. another CPS?
1994 4.0L 4WD -
here's whats goin on with it.
it keeps randomly shutting off, and when it does you have to turn the key off and let it sit for a minute or two, then it fires back up and will usually go for a few minutes before stalling out and i have to let it sit again.
so last night i replaced the crank sensor with a new one (aftermarket), it drove fine for about a mile and then started misfiring real bad and stalled out. would start back up but still misfire. i found that if i disconnected the battery each time it stalled, it would run for about a mile at a time before it would start to misfire and stall out.
i put my old crank sensor back in, no more misfiring but of course it still stalls out randomly. i've also noticed the speedometer drops to zero when it stalls.
should i try another crank sensor? what else can i be checking? what are some other likely causes?
i've also swapped the ASD (autoshutdown) relay, no luck.
fuel pressure at idle with vacuum line connected/disconnected is within spec, as is the fuel pressure bleed-down, according to specs from alldata.
here's whats goin on with it.
it keeps randomly shutting off, and when it does you have to turn the key off and let it sit for a minute or two, then it fires back up and will usually go for a few minutes before stalling out and i have to let it sit again.
so last night i replaced the crank sensor with a new one (aftermarket), it drove fine for about a mile and then started misfiring real bad and stalled out. would start back up but still misfire. i found that if i disconnected the battery each time it stalled, it would run for about a mile at a time before it would start to misfire and stall out.
i put my old crank sensor back in, no more misfiring but of course it still stalls out randomly. i've also noticed the speedometer drops to zero when it stalls.
should i try another crank sensor? what else can i be checking? what are some other likely causes?
i've also swapped the ASD (autoshutdown) relay, no luck.
fuel pressure at idle with vacuum line connected/disconnected is within spec, as is the fuel pressure bleed-down, according to specs from alldata.
Last edited by rompnXJ; 07-01-2011 at 02:31 PM.
07-01-2011, 05:50 PM
#3
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battery voltage is 13.9 at idle, battery always stays charged and it cranks fine.
also, i replaced the crank sensor again today with a new one from autozone. no more misfiring, but the random stalling is still there. except this time, instead of random stalling, it stalls randomly only when i try to give it gas.
the pcv/crankcase breather-to-airbox hose has been disconnected for a few weeks, today i put a new hose on it and it seems to somehow be running fine now. i have no idea how that could have anything to do with it. i need to test drive it some more to confirm its fixed, but in case its not... what else can i check?
also, i replaced the crank sensor again today with a new one from autozone. no more misfiring, but the random stalling is still there. except this time, instead of random stalling, it stalls randomly only when i try to give it gas.
the pcv/crankcase breather-to-airbox hose has been disconnected for a few weeks, today i put a new hose on it and it seems to somehow be running fine now. i have no idea how that could have anything to do with it. i need to test drive it some more to confirm its fixed, but in case its not... what else can i check?
Last edited by rompnXJ; 07-01-2011 at 05:55 PM.
07-01-2011, 07:03 PM
#5
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Year: 1992
Model: Cherokee
Engine: 4.0L HO
Did it suddenly start doing this or did it work itself into something this bad? Try checking your tps, idle sensor, map, and even your o2 sensor. It could even be a computer problem....
07-01-2011, 08:02 PM
#7
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Year: 2001
Model: Cherokee (XJ)
Engine: 4.0L I6 Power Tech
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07-01-2011, 08:57 PM
#8
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TPS is a couple weeks old, there are no codes in it, and it always has good fuel pressure even when it wont start back up.
tonight i went wheeling with it for a good couple hours thru some mud, deep water, hills, stuff like that; it never even hinted at stalling. im gonna keep my fingers crossed that it stays this way.
but a failing distibutor could cause random stalling, even without it ever misfiring? also, is the cam sensor built into the distributor or does it not have one?
the only time the jeep has ever misfired was when i replaced the crank sensor with a junk aftermarket sensor. also, ive never seen an o2 sensor cause a car to stall, u can drive without it all day long; and if it was bad it would run like sh**.
whatever yall think the most likely culprits are (besides fuel pump, ckp, tps), will go on my to-do list.
thanks for the help.
tonight i went wheeling with it for a good couple hours thru some mud, deep water, hills, stuff like that; it never even hinted at stalling. im gonna keep my fingers crossed that it stays this way.
but a failing distibutor could cause random stalling, even without it ever misfiring? also, is the cam sensor built into the distributor or does it not have one?
the only time the jeep has ever misfired was when i replaced the crank sensor with a junk aftermarket sensor. also, ive never seen an o2 sensor cause a car to stall, u can drive without it all day long; and if it was bad it would run like sh**.
whatever yall think the most likely culprits are (besides fuel pump, ckp, tps), will go on my to-do list.
thanks for the help.
Last edited by rompnXJ; 07-01-2011 at 09:02 PM.
07-01-2011, 09:11 PM
#9
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Year: 1992
Model: Cherokee
Engine: 4.0L HO
I've actually had mine continuously stall on the highway for a week before i found that my o2 sensor was faulty. I think my seafoam ruined my o2 sensor.
07-01-2011, 09:28 PM
#10
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except for the stalling, did it run good with the bad o2 ?
and btw, yes this problem came on all of a sudden about 3 weeks ago, it seems to only act up on the weekends lol.. but this last week its been doing it every day.
07-02-2011, 12:35 AM
#11
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Year: 1992
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It would drive fine then lose power even on even road. Finally my friend told me to check the o2 sensor and i was sceptical but he was right.
07-02-2011, 04:17 PM
#13
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