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99 PCM replace/update

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Old Nov 24, 2019 | 06:02 PM
  #316  
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Those signals look good! I guess it's time to get the black tape!

Artifact from probably the probe cables too near plug or coil wires.
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Old Nov 24, 2019 | 06:15 PM
  #317  
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Originally Posted by Dave51
Those signals look good! I guess it's time to get the black tape!

Artifact from probably the probe cables too near plug or coil wires.

No quite sure what you mean about the tape Dave, is this suggesting probes touching or pulling signal from something else?

also what is the artifact? This has been fun tinkering with, but no idea what I'm doing.
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Old Nov 24, 2019 | 06:33 PM
  #318  
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Artifact is those extraneous spikes in the waveforms, most notably the camshaft. They are caused by electrical interference by other signals. Since the coil and spark plug wires have high voltage, they can cause contamination if they are too near your signal cables. Move the cables away from all other wires to see if you can clear that out.
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Old Nov 24, 2019 | 06:36 PM
  #319  
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And if you can't clear them out, I think we have to figure out why they're there, because they shouldn't be.
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Old Nov 24, 2019 | 06:51 PM
  #320  
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Originally Posted by Dave51
Move the cables away from all other wires to see if you can clear that out.
If that doesn't work, try measuring the signals at the sensor connectors.
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Old Nov 24, 2019 | 07:02 PM
  #321  
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Originally Posted by Dave51
I guess it's time to get the black tape!
Either cover up a leaky wire or the CEL!
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Old Nov 24, 2019 | 07:53 PM
  #322  
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Cmps At pcm

After moving the cmps plug i tried at the pcm again, then I went for direct to sensor and grounded to battery.

Last edited by 4x4jeepmanthing; Nov 24, 2019 at 07:58 PM.
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Old Nov 24, 2019 | 07:58 PM
  #323  
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At sensor harness, grounded to battery
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Old Nov 24, 2019 | 08:36 PM
  #324  
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With the measurement tool, can you measure how many volts those spikes are?

Is that the same pickup coil you've had throughout this ordeal (I tried to read back to figure that out but this is a BOOK!)?
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Old Nov 24, 2019 | 10:06 PM
  #325  
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yes it is the same cmps, its got about 30,000 miles on its after being replaced for p0340 about 2 yrs ago. it is mopar.

junk sensor?

Last edited by 4x4jeepmanthing; Nov 24, 2019 at 10:31 PM.
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Old Nov 24, 2019 | 10:53 PM
  #326  
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Originally Posted by 4x4jeepmanthing

yes it is the same cmps, its got about 30,000 miles on its after being replaced for p0340 about 2 yrs ago. it is mopar.

junk sensor?
I thought we had established absolutely without question the cam sensor has been replaced after your sync code started ?

or in fact an entire new distributor body with sensor included,,, even a used one ?
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Old Nov 24, 2019 | 11:32 PM
  #327  
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We had established that I had a code p0340 April 2018, I had replaced the cmps at this time. May 2018 p1391 arrived with a CEL.
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Old Nov 25, 2019 | 01:09 AM
  #328  
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Originally Posted by 4x4jeepmanthing
We had established that I had a code p0340 April 2018, I had replaced the cmps at this time. May 2018 p1391 arrived with a CEL.
long thread..interesting timing on the new code..1 month after a new cam sensor, and along with the spike in voltage, suggests that could be the issue, keep checking

I obtained a number of used OEM sensors, and that is their entire job in life, to be test beds, they are in a little bag under my passenger seat
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Old Nov 25, 2019 | 04:44 AM
  #329  
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Originally Posted by 4x4jeepmanthing
junk sensor?
I suppose what you're really asking is

If I replace the pickup coil will that solve the problem?
and I do not know that. But since 1391 can be generated by

P1391-INTERMITTENT LOSS OF CMP OR CKP

When Monitored: Engine running or cranking.

Set Condition: When the failure counter reaches 20 for 2 consecutive trips.

POSSIBLE CAUSES:
...
IRREGULAR LAB SCOPE PATTERN OF CMP SIGNAL
...
I think we're REAL close. With an otherwise normal and synced CPS signal that artifact (I believe it's coil) would seem to be the culprit. I think it's either the CPS, the distributor cap, rotor or somewhere along the harness to the ECU.

Last edited by Dave51; Nov 25, 2019 at 04:48 AM.
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Old Nov 25, 2019 | 08:24 AM
  #330  
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Originally Posted by awg
long thread..interesting timing on the new code..1 month after a new cam sensor, and along with the spike in voltage, suggests that could be the issue, keep checking

I obtained a number of used OEM sensors, and that is their entire job in life, to be test beds, they are in a little bag under my passenger seat
quite a lengthy thread, but its been a great chance to learn. I even ended up replacing some things I never would have known I needed to replace.

I suppose ill try a cmps either echlin or J.y. but i dont figure ide find a mopar cps in the JY to likely.

harness is newly reworked,cap/rotor new with motor. other than a timing chain we have gone through about everything.
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