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Old May 11th, 2019, 09:48
RCP Phx RCP Phx is offline
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P1391 - Temp loss of CMP/CKP

Besides connections, anything that I should be looking for?
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Old May 11th, 2019, 12:36
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Tim_MN Tim_MN is offline
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Re: P1391 - Temp loss of CMP/CKP

Distributor index / Cam Sensor Synchronization.



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/bucking/stalling, often over bumps or right hand turns or when going into reverse.
(2) shorted out the Fuel pump/ECU power wire.

Possible causes
- Faulty Camshaft Position (CMP) Sensor
- Camshaft Position (CMP) Sensor harness is open or shorted
- Camshaft Position (CMP) Sensor circuit poor electrical connection.
-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
-CRANKSHAFT POSITION SENSOR CONNECTOR/WIRING
-FAULTY CRANKSHAFT POSITION SENSOR


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.

Read this also : http://www.jeepforum.com/forum/f19/j...e-fix-3487474/

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 service manual.
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Last edited by Tim_MN; May 12th, 2019 at 09:02.
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Old May 12th, 2019, 13:18
RCP Phx RCP Phx is offline
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K.I.S.S.

I hope! I started with the easiest/simplest item, the cam sensor. Everything was looking good with the connection so I removed the cap. Didn't notice anything and was about to check it with a ohmmeter (which I would need to grab out of the other garage) so I was going to check the gears for end play/radial play. Then I saw something unusual, the magnet is hanging on the tab of the rotor! I can't get a Mopar sensor today sob I just ordered one.
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Old May 16th, 2019, 09:41
RCP Phx RCP Phx is offline
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Re: P1391 - Temp loss of CMP/CKP

Well mines fixed better than ever, for months I've had a tick which made me think I needed to check my lifter per-load. Turns out that noise is gone too!
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