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engine cutting out

A

alwayzAMC

NAXJA Forum User
Location
maine
hi all,

am having an issue with my 99 XJ, when driving, the engine seems like it is cutting out, feels like a govener or something cutting the power off to it, best way i can describe it, is like driving a newer style chevy truck at 99 mph when the computer shuts power off to the engine to prevent you from going any faster. have done some searches here, and seems it could be my CPS, part is $85.00 so don;t really want to replace it without knowing for sure. there is only 1 code coming up on the computer, and that is one of my O2 sensors.

any other ideas? checked wires from CPS they seem ok, battery connections seem fine. is strange.
 
ive had exactly the same feeling one time when i left the cps wiring on the exhaust mani, and it grounded out. but you said you checked that....
 
Remove connector for crank sensor. Buy a can of electrical contact cleaner (good to have around). Thoroughly spray the connector. Add a small dab of dielectric grease to the connector and reconnect it.

On occasion, debris gets into this connector and creates some resistance, which results in an intermittent loss of the crank signal to the computer, which could result in the symptoms you are seeing.

If this doesn't resolve it, it could be the crank sensor itself. Or the ignition coil.

This doesn't sound like an oxygen sensor to me, although I would certainly work on resolving your code.

If you have one code that is ignored and then you have a NEW problem, it can get real confusing, real fast.

Post the EXACT code for the O2 sensor you have and we will comment.
 
I am having the same excact issue with my 99 right now only its not throwing any codes. Last night while driving down the freeway at about 65mph the jeep just died. Still had power lights radio ect were all on. I pulled off the freeway and check fuel at the fuel rail and had plenty of pressure. Tried to start it in nuetral and no dice after about 10 mins it started back up and ran fine the whole way home.
 
i had the garage put in a new CPS drove it home, and same issue, my code reader won;t tell me whether is the downspout O2, or the post cat o2, the garage i took it to does, is the downspout, they were going to replace it, but cannot turn out the O2 sensor. they will have to weld in a piece of pipe, or something. am on the road quite a bit, so don;t drive it often, and have even less time to work on it. so now i am back where i started, it is in the barn now, cooling off. am going to get under it more, now that is not raining and see what else i can find, am going to retrace my wires from the cps more closely, maybe one is cut, or bad or something. my next thought from here is fuel pump. have had vehicles with bad O2 sensors before, so am really not thinking this is what is causing this problem. My garage is about an hour north of where i live, if i don;t find it today will do more there, am just hoping it will make it there.
 
QCXJ8879 said:
I am having the same excact issue with my 99 right now only its not throwing any codes. Last night while driving down the freeway at about 65mph the jeep just died. Still had power lights radio ect were all on. I pulled off the freeway and check fuel at the fuel rail and had plenty of pressure. Tried to start it in nuetral and no dice after about 10 mins it started back up and ran fine the whole way home.
Click to expand...

this is quite different from my problem,, mine i still have oil pressure, voltage at right spot, is as if something is killing the electrical supply to the coil pack, just like a computer shutting down the engine at certain speed, ie GM at 99 MPH, stall for a second, get power again, stall again, etc etc, till i nail the gas for a second, and will come out of it, then back at it again maybe in 1 minute, maybe in 10.
 
cherry that o2 sensor boss with an oxy torch it should screw right out. don't force it cold or you will wipe out the threads, or break it off in the pipe. are you getting soot at the tailpipe? are the spark plugs black? try to run it with the o2 unplugged. see if it changes any symptoms. a skewed o2 can and will cause plugs to misfire due to carbon fouling because it is too rich.
 
alwayzAMC said:
this is quite different from my problem,, mine i still have oil pressure, voltage at right spot, is as if something is killing the electrical supply to the coil pack, just like a computer shutting down the engine at certain speed, ie GM at 99 MPH, stall for a second, get power again, stall again, etc etc, till i nail the gas for a second, and will come out of it, then back at it again maybe in 1 minute, maybe in 10.
Click to expand...

The ignition coil itself is also suspect here. If that is flaky, it can give symptoms similar to the crank sensor.
 
birchlakeXJ said:
The ignition coil itself is also suspect here. If that is flaky, it can give symptoms similar to the crank sensor.
Click to expand...


yeah the more i thought about it the more of an idiot i must be to think of a fuel pump issue, has to be electrical somewhere. last thing i wantd to trace is an electrical issue with no codes coming up. will be looking closely at wires, grounds, coil, battery connections, it all looked ok at a good look, but must be something i missed somewhere. will be picking it apart in the morning.
 
amcjeep said:
cherry that o2 sensor boss with an oxy torch it should screw right out. don't force it cold or you will wipe out the threads, or break it off in the pipe. are you getting soot at the tailpipe? are the spark plugs black? try to run it with the o2 unplugged. see if it changes any symptoms. a skewed o2 can and will cause plugs to misfire due to carbon fouling because it is too rich.
Click to expand...

they did,i might if i have time tomorrow put a torch on it myself if i get up to my garage. there isn;t any foulings that i can tell. haven;t worked on any chrysler products in a while. but can;t imagine the O2 sensors killing power to the engine, but they have done dumber things. this has come on within the last couple weeks, was running fine with the 02 code for weeks prior to that.
 
Do you seem to lose all power for a second or so and then it comes back to life? If so, before getting dirty under the XJ, check out the ignition switch wiring.

I had an intermittent power loss that was caused by bad connections at the ignition switch in the column. It could happen any time while driving or when I would bump the column with my knee. If it didn't come back up on its own in about a second I could tap the bottom of the column and it power would return. It was just old corroded connections at the switch.

If the problem is that the engine seems to stutter or bog like the fuel has been cut it could be the o2 sensor - usually symptoms are it happens around the same RPM every time, around 1750-2000 rpm was most common when I had this issue, and it picks back up if you get on the gas.
 
I broke down on my way home from work after buying the crankshaft position sensor. Had some buddies come help me change it on the side of the road and so far so good. I drove it all weekend with no problems and I got to work this morning with no problems. I think I am still going to pick up a new ignition coil and throw it in my parts box in the jeep just in case.
 
alwayzAMC said:
hi all,

am having an issue with my 99 XJ, when driving, the engine seems like it is cutting out, feels like a govener or something cutting the power off to it, best way i can describe it, is like driving a newer style chevy truck at 99 mph when the computer shuts power off to the engine to prevent you from going any faster. have done some searches here, and seems it could be my CPS, part is $85.00 so don;t really want to replace it without knowing for sure. there is only 1 code coming up on the computer, and that is one of my O2 sensors.

any other ideas? checked wires from CPS they seem ok, battery connections seem fine. is strange.
Click to expand...
Hi, I am having exactly the same problem. I took it to a Jeep dealer workshop and the code for the O2 sensor came up but it said it earthed somewhere. I also looked for open or chafed wires but couldn't find any. Hope we find the culprit. I will follow this thread closely:smsoap:
 
Leonkruger7 said:
Hi, I am having exactly the same problem. I took it to a Jeep dealer workshop and the code for the O2 sensor came up but it said it earthed somewhere. I also looked for open or chafed wires but couldn't find any. Hope we find the culprit. I will follow this thread closely:smsoap:
Click to expand...

i went through my ignition, all that seemed fine. tore into the column, that looked fine, was able to run the engine wile playing with all the wires, and nothing there, same with the wires underneath.

an taking it in again tomorrow, having them change the pipe, it does need it anyway, and having the O2 sensor replaced.

i got under there and looked while i had it in the barn, there is what looks like a steel based pre converter, before the first O2 sensor, will know for sure when i see it off the vehicle.

i will let you know if i find anything else out, if you find out what is wrong with yours in the meantime, might give me something else to try
 
ok, an update, picked up my jeep from the garage yesterday,. and problem has seemed to go away. will be taking it on a longer ride tomorrow, so if it comes back, will update again. but so far problem fixed. next item on the list 4WD light
 
alwayzAMC said:
ok, an update, picked up my jeep from the garage yesterday,. and problem has seemed to go away. will be taking it on a longer ride tomorrow, so if it comes back, will update again. but so far problem fixed. next item on the list 4WD light
Click to expand...
Thats awesome!! I truly hope its sorted for good. Please let me know what they did to cure it
 
Leonkruger7 said:
Thats awesome!! I truly hope its sorted for good. Please let me know what they did to cure it
Click to expand...

they replaced the pipe from the manifold and put in a new O2 sensor. and drove it up north an hour and back yesterday, not so much as a hiccup from it. the code was only a temp code, and did not trip the service engine soon light.

so it appears to be fixed, so if you are having the same problems and no service engine soon light is on, it maybe just a temp code in the computer still, mine was O2 sensor voltage reading was too high.
 
always AMC, could you restate the fix? You mentioned a "pipe from the manifold" and the O2 sensor. What pipe are you talking about?

I'm having a similiar issue - has only happened a few times.

while snoozing in my xj, AC on, engine cuts off and shuts down after about 15 minutes. Another time took off from a stop light and had a nice hiccough. Then another time while driving about 60mph, had a short hiccough again. Doesn't seem to be a tranny issue, just seems to cut out for a split second - though not sure of course. That's why I"m here!

thanks
 
my o2 went out and i unplugged it and drove her around and she ran great.. try just unplugging.... my engine had a horrible cut out issue once she warmed up... so don't think that the o2 wont cause the cut out for one minute cause it will!!! lol good luck bro... keep us updated!
 
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