1999 Jeep Cherokee 1999 Jeep Randomly Shuts Down

Tiny
RCONNER@GREENVILLENC.GOV
  • MEMBER
  • 1999 JEEP CHEROKEE
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 160,000 MILES
My 1999 Jeep started randomly shutting down, (cutting off) usually at low speeds. It starts right back up, but randomly cuts off while driving. When it happens, the check engine light comes on, the voltage drops and the RPM needle reacts. I had the crank sensor replaced, but that was not it. The diagnostic tests don't show anything wrong; however the computer will not res-set when cleared. The fuel pump is fine. What could it be?
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Thursday, January 7th, 2010 AT 9:20 AM

11 Replies

Tiny
RACEFAN966
  • EXPERT
Is there any codes stored? If so what are the codes? What do you mean by computer won't reset?
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Thursday, January 7th, 2010 AT 10:20 AM
Tiny
RCONNER@GREENVILLENC.GOV
  • MEMBER
Everytime the mechanic clears the computer, it shows that it has already been cleared. There are no readings and no codes.
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Thursday, January 7th, 2010 AT 11:11 AM
Tiny
RACEFAN966
  • EXPERT
Now it only dies when you let it come to idle speed and no other time? If this is correct has the TPS or the Idle Air Control Motor checked? Either of these could be bad and not set a code. I also need as if it seems to be temperature related or will this happen just any time it wants? Do you have a digital multi meter to run a couple of tests if needed? Get back to me and we will go from there.
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Friday, January 8th, 2010 AT 10:00 AM
Tiny
RCONNER@GREENVILLENC.GOV
  • MEMBER
I've not been in touch with the mechanic since late last week- it started off "bucking" while driving at higher speeds- but usually when decelerating. It would do it every now and then at first, then got more frequent. Sometimes it would shut down completely - and once it took a while to get it started again, but usually it would re-start. The check engine light would flash, but not stay on. It is not temperature related. The mechanic said he was going to drive it around until it completely shut down so he could figure out what was going on. He does not think it is the gas pump or the ignition.
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Monday, January 11th, 2010 AT 7:57 AM
Tiny
RACEFAN966
  • EXPERT
Ok I need to know if this is a Grand Cherokee or not. I would check the coil on boot ends and the coil pack. The boots should be between 250 to 1000 ohms. Also check them for any cracks. Let me know what you find.
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Monday, January 11th, 2010 AT 10:09 AM
Tiny
RCONNER@GREENVILLENC.GOV
  • MEMBER
It is not a Grand Cherokee. Just a sport model Jeep Cherokee. I'll pass that on.
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Monday, January 11th, 2010 AT 10:15 AM
Tiny
RACEFAN966
  • EXPERT
Ok thanks that changes what ignition system is has. A standard Cherokee has cap, rotor and wires and a coil. Now I would check the wires for the ohms making sure it don't excede 1000 ohms per inch. I also would check the primary side and secondary side of the coil. Primary resistance should be.95 to 1.20 ohms, and the secondary resistance should be 11,300 to 15,300 ohms. Let me know what you find.
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Tuesday, January 12th, 2010 AT 10:07 AM
Tiny
RCONNER@GREENVILLENC.GOV
  • MEMBER
The computer hasn't been reading anything, so he did change the coils in case that was the problem. It didn't solve it - so the next step is a new computer. I'll let you know if that fixes it.
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Friday, January 15th, 2010 AT 1:58 PM
Tiny
RACEFAN966
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Let me know if the computer fixes it. We will take it from there.
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Saturday, January 16th, 2010 AT 8:46 AM
Tiny
RCONNER@GREENVILLENC.GOV
  • MEMBER
It WAS the computer. We changed the crank sensor and the coils, which did not fix it. We put in a new computer, and that took care of it. It took nearly two weeks to figure it out.
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Wednesday, January 20th, 2010 AT 10:01 AM
Tiny
RACEFAN966
  • EXPERT
Yea some times it takes a bit to find the problems. I am glad it is fixed however. Great job and if you have any more questions just ask.
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Wednesday, January 20th, 2010 AT 10:48 AM

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