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replaced CPS now I have coil pack codes?

SeansBlueXJ

NAXJA Forum User
I was out in my 2000 4.0 running errands I had a moment when it cranked and didn't start, then tried again started up. This happened again and then it threw the code P1391. Then after my last time starting it I had several times it stalled out etc. Finally got it running consistent and then headed home. Got home OK but then was having several issues starting. I changed both the Crank and Cam position sensors, left the battery disconnected etc. The jeep still has the same issues starting, I need to go through several cycles of cranking it. Well when it starts, it will idle fine, but any increase on the throttle, or any attempt to move throws it into rough idle, and most likely a stall.

The codes I am pulling now however are different. p0351/0352/0353 Ignition Coil A/B/C primary/secondary circuit. So any thoughts? I do not just want to go chasing gremlins and throwing money I don't have at this time. This is still my daily and I can't afford to have it down long. Please help!
 
I think those codes are telling you where you should start. Something's not right with the new parts/installation!
 
Did you buy genuine Jeep sensors ?


I suggest you problem solve for the P1391.

P1391 - Intermittent Loss of CMP or CKP Signal. Loss of the Cam Position Sensor or Crank Position sensor signal has occurred.

P1391 – Possible symptoms:
(1) random misfire/stumble/stalling, often over bumps or right turns and when going into reverse.
(2) shorted out the Fuel pump/ECU power wire.

Possible causes
- Faulty CamshaftPosition (CMP) Sensor
- Camshaft Position (CMP) Sensor harness is open or shorted
- Camshaft Position (CMP) Sensor circuit poor electrical connection.

Symptoms:

CMP SENSOR OUT OF SYNC
-DAMAGED TONE WHEEL/FLEX PLATE (CRANKSHAFT)
-DAMAGED TONE WHEEL/PULSE RING (CAMSHAFT)
-IRREGULAR LAB SCOPE PATTERN OF CMP SIGNAL

INTERMITTENT CKP SIGNAL LOSS WHEN WIRING IS WIGGLED
-IRREGULAR LAB SCOPE PATTERN OF CKP SIGNAL
-WIRING HARNESS INTERMITTENT

INTERMITTENT CMP SIGNAL LOSS WHEN WIRING IS WIGGLED
-SENSOR CONNECTOR/WIRING
-CAMSHAFT POSITION SENSOR
-CKP SENSOR CONNECTOR/WIRING
-CRANKSHAFT POSITION SENSOR

Often replacing the sensor fixes this code, but not necessarily. Therefore it's important to check the following:

• Check that the wiring isn't routed too close to to sharp metal edges, or to hot exhaust parts.
• Visually inspect the wiring at the sensor for any burn marks, discoloration indicative of melting or chafing of insulation
• Visually inspect the cam sensor for damage
• Visually inspect the reluctor wheel inside the alternator. Make sure the magnet is firmly attached.
• If all checks out okay, then replace the sensor.

If you buy any OBD-II engine sensors, make sure to buy genuine Jeep sensors.

Potential Fixes:

Fix #1:
Inspect your wire harnesses for damaged wires, chafed insulation, or failed wire splices. Use a volts/ohms multi-meter to check the resistance of the ground wire circuits from each sensor. Replace corroded ground wires/connectors and clean ground wire connection points.

Fix #2:
Timing may off. Re-index the distributor/cam sensor per the FSM instructions, or replace faulty distributor/cam sensor pickup module.

Google Scan Tools, O-Scopes and Toothpicks, and read the article.

A mis-indexed distributor/cam sensor may exhibit surging, light bucking or intermittent engine misfiring. This will most likely occur when the vehicle is at operating temperature and under a light load at approximately 2,000 rpm. The proper indexing procedure must be used as outlined in the Jeep Service Manual.
 
Last edited:
I was out in my 2000 4.0 running errands I had a moment when it cranked and didn't start, then tried again started up. This happened again and then it threw the code P1391. Then after my last time starting it I had several times it stalled out etc. Finally got it running consistent and then headed home. Got home OK but then was having several issues starting. I changed both the Crank and Cam position sensors, left the battery disconnected etc. The jeep still has the same issues starting, I need to go through several cycles of cranking it. Well when it starts, it will idle fine, but any increase on the throttle, or any attempt to move throws it into rough idle, and most likely a stall.



The codes I am pulling now however are different. p0351/0352/0353 Ignition Coil A/B/C primary/secondary circuit. So any thoughts? I do not just want to go chasing gremlins and throwing money I don't have at this time. This is still my daily and I can't afford to have it down long. Please help!



Same thing happened to mine when the CMP sensor had failed. Be sure you indexed it correctly.

If you look on the synchronizer body there’s a small pinhole in it and the rotor inside it.

Loosen the bolt on the engine block so you can turn the entire synchronizer body

Turn it so you can line the holes up ( may have to bump the starter so you can get it close)

Put the paper clip through the holes and tighten the bolt.

Install sensor cap and plug it in. Then try to start it.


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Put in Mopar sensors. will not start. At least with the Auto store stuff I could get it to run, it would idle fine but die out with any throttle... Related? Maybe not. But still not starting. Thoughts?
 
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