jeep will turn over but not start
Senior Member
Joined: Sep 2009
Posts: 629
Likes: 0
Model: Cherokee
Just thought i'd through down a few links for ya!
http://www.jeepforum.com/forum/f11/c...-maybe-889010/
http://www.jeepforum.com/forum/f11/w...s-test-610958/
I'm thinking CPS at this point.
Good luck!
http://www.jeepforum.com/forum/f11/c...-maybe-889010/
http://www.jeepforum.com/forum/f11/w...s-test-610958/
I'm thinking CPS at this point.
Good luck!
Senior Member
Joined: Sep 2009
Posts: 629
Likes: 0
Model: Cherokee
CF Veteran
Joined: Nov 2009
Posts: 1,261
Likes: 0
From: New Jersey
Year: 1996
Model: Cherokee
Engine: 4.0 HO
Alrighty, I just went through this whole ordeal so I'll help you out. The CPS is the crankshaft positioning sensor. It's located on the top of the bellhousing. It monitors the crankshaft rotation and tells the PCM when to produce spark. You can test the resistance with a multimeter by setting it to 10k-20k and placing the terminals between B and C as seen in this picture http://fototime.com/78EA763821BA137/standard.jpg . It should be zero resistance, if there is any resistance at all replace it. Here is a picture of the location of the senor itself 
If the CPS doesn't fix it, let me know and I'll give you the rest of the test procedure.
If the CPS doesn't fix it, let me know and I'll give you the rest of the test procedure.
Senior Member
Joined: Apr 2009
Posts: 922
Likes: 2
From: Grand Haven, Michigan
Year: 1998, 1999
Model: Cherokee
Engine: 4.0
Here's a good article I saved for this problem...
Jeep Cherokee Dies In The Heat
Q. Okay, here's my stalling story, I have a 1993 Jeep Cherokee with 160,000 miles which ran very well with no problems until three days ago. I like everyone else with this problem took it to a mechanic. and he checked the throttle body cleaned it, changed the fuel filer, changed the Crankshaft Position Sensor (CPS) but still stalls.
He also checked the psi of the fuel pump, put the car on a diagnostic machine, no codes. Also checked and changed the relays in the fuse box under the hood. Pulled on every wire harness, still stalls but only when driving. You can leave the car in idle and never stalls.
Now here's the thing, I did some testing with friend while the car had stalled with the key still in the on position the car would not start, so we pulled a spark plug wire and put a screwdriver bit inside the plug and held it to the engine cranked the car and no spark.
So I turned off the ignition and waited about 20 to 30 (minutes?) the jeep started right up and there was spark coming from that wire. I hate to be long winded but i am trying to keep costs down and have not replaced the main PCM, coil or fuel pump. Could a blocked catalytic converter also cause this no spark thing after the jeep has stalled? Is there something tripping the auto shutdown relay??
Bill
A. First off, a bad catalytic converter will not cause a no spark condition.
These checks must be done when the vehicle won't start or they will not help track down the problem. If you look at the wiring diagram, you should have power to the dark green/orange wire at the coil. This is the feed from the ASD relay.
Flashing the black/gray wire to ground should generate a spark from the coil wire. If it does, the ASD relay and coil are good. If you flash the gray wire at the PCM connector and generate a spark, everything up to the PCM is good.
All that leaves is the Crankshaft Position Sensor (CPS), the wiring or the PCM itself.
To test the CPS, near the rear of intake manifold, disconnect the sensor harness connector from the main wiring harness. Place an ohmmeter across terminals B and C.
Ohmmeter should be set to 1K-to-10K scale for this test. The meter reading should be open (no resistance). Replace the sensor if a low resistance is indicated.
If all of this checks out good, you probably have a bad PCM. You might also want to read Handling No Trouble Code Problems.
Q. Okay, here's my stalling story, I have a 1993 Jeep Cherokee with 160,000 miles which ran very well with no problems until three days ago. I like everyone else with this problem took it to a mechanic. and he checked the throttle body cleaned it, changed the fuel filer, changed the Crankshaft Position Sensor (CPS) but still stalls.
He also checked the psi of the fuel pump, put the car on a diagnostic machine, no codes. Also checked and changed the relays in the fuse box under the hood. Pulled on every wire harness, still stalls but only when driving. You can leave the car in idle and never stalls.Now here's the thing, I did some testing with friend while the car had stalled with the key still in the on position the car would not start, so we pulled a spark plug wire and put a screwdriver bit inside the plug and held it to the engine cranked the car and no spark.
So I turned off the ignition and waited about 20 to 30 (minutes?) the jeep started right up and there was spark coming from that wire. I hate to be long winded but i am trying to keep costs down and have not replaced the main PCM, coil or fuel pump. Could a blocked catalytic converter also cause this no spark thing after the jeep has stalled? Is there something tripping the auto shutdown relay??
- 1993 Jeep Cherokee
- 4.0 liter
- Automatic transmission
- 160,000 miles
- Fuel injection
Bill
A. First off, a bad catalytic converter will not cause a no spark condition.
These checks must be done when the vehicle won't start or they will not help track down the problem. If you look at the wiring diagram, you should have power to the dark green/orange wire at the coil. This is the feed from the ASD relay.
Flashing the black/gray wire to ground should generate a spark from the coil wire. If it does, the ASD relay and coil are good. If you flash the gray wire at the PCM connector and generate a spark, everything up to the PCM is good.
All that leaves is the Crankshaft Position Sensor (CPS), the wiring or the PCM itself.
To test the CPS, near the rear of intake manifold, disconnect the sensor harness connector from the main wiring harness. Place an ohmmeter across terminals B and C.Ohmmeter should be set to 1K-to-10K scale for this test. The meter reading should be open (no resistance). Replace the sensor if a low resistance is indicated.
If all of this checks out good, you probably have a bad PCM. You might also want to read Handling No Trouble Code Problems.
CF Veteran
Joined: Nov 2009
Posts: 1,261
Likes: 0
From: New Jersey
Year: 1996
Model: Cherokee
Engine: 4.0 HO
Also, if it's not the CPS, it could be the Camshaft Positioning Sensor, aka the pick-up coil or stator. It's located under the distributor cap and also controls the spark. This is a good read and explanation on how to change one out. If your's is 193,000 miles old like mine was though, it just breaks because it's so brittle. If anyone ever has to change one out, try to use leverage under where the input wires are to avoid snapping it. Here's the link. http://www.lunghd.com/Tech_Articles/...lse_Stator.htm
Senior Member
Joined: Sep 2009
Posts: 629
Likes: 0
Model: Cherokee
Also, if it's not the CPS, it could be the Camshaft Positioning Sensor, aka the pick-up coil or stator. It's located under the distributor cap and also controls the spark. This is a good read and explanation on how to change one out. If your's is 193,000 miles old like mine was though, it just breaks because it's so brittle. If anyone ever has to change one out, try to use leverage under where the input wires are to avoid snapping it. Here's the link. http://www.lunghd.com/Tech_Articles/...lse_Stator.htm
Senior Member
Joined: Apr 2009
Posts: 922
Likes: 2
From: Grand Haven, Michigan
Year: 1998, 1999
Model: Cherokee
Engine: 4.0
CF Veteran
Joined: Nov 2009
Posts: 1,261
Likes: 0
From: New Jersey
Year: 1996
Model: Cherokee
Engine: 4.0 HO
If you ever have a no-spark condition, I've been there, done that, and have all the information due to extensive research, haha. My CPS crapped out and took the coil and Camshaft Positioning Sensor with it, so at first I was a bit confused because the CPS tested bad and the new one didn't fix it at first. Then i pieced the puzzle together and it runs again. Woo!
Newbie
Joined: Jul 2014
Posts: 21
Likes: 0
Model: Cherokee
Same issue
I'm not sure the year on my engine but the previous owner thought it was 98 or 99 but was unsure. Any help will be greatly appreciated.
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