Can advancing Cam 4deg, cause a P1391 code

[rwkhaussupply]

Without going in to the whole speal.

Cam advanced 4 deg. Cam had 1.5deg built in, after degree wheel read.

Keep getting P1391 CEL and have replaced both CamPS and CPS with Mopar 2 times each. still get the code popping up once warmed up and 2 to 4 heat cycles.

Then read this in a posting somewhere:
P1391
Definition: CMP or CKP signal intermittent condition
Explanation: The ECM detected the actual CMP position disagreed with the expected CMP level
Probable cause: 1. Timing belt or chain stretched or jumped. 2. Defective CMP sensor

So, Thoughts? anyone hear of this? I have one other idea that could be my issue. I made a MAP adjuster as shown online and wondering if that is interfering with ground or 5V system that both the sensor also use.

[jsawduste]

Did you reindex the cam sensor ?

[jeepxj3]

The 5.5* total advance in the cam could be causing too big of a dependency between the cam and crank position sensors position timing signals when the ecu sees these values. Either run the cam without the additional 4* advance or have your tuner make ecu changes to allow for the bigger cam-crank signal differences.

This is a normal feature in the ecu to detect the cam-crank signal timing differences to detect for things like stretched timing chain, etc.

[SilverXJ]

The 5.5* total advance in the cam could be causing too big of a dependency between the cam and crank position sensors position timing signals when the ecu sees these values.

That is incorrect. If the cam sensor is indexed correctly there will be no discrepancy.

[rwkhaussupply]

The 5.5* total advance in the cam could be causing too big of a dependency between the cam and crank position sensors position timing signals when the ecu sees these values.

That is incorrect. If the cam sensor is indexed correctly there will be no discrepancy.

So when you say "If the cam sensor is indexed correctly". Are you meaning that as Jeep meant it to be with the hole in dist holo wheel to dist lined up and dropped in to index on dist body clamp?

I have cut off the index tabs so that it can be rotated, but not really know what to do there and how to get it "right" if that is the solution? If it is? Then the dist should only be turned counter clockwise a tad right?

[jsawduste]

My highly unscientific process for the dist. based engine is to rotate the dist CW/CCW till you find the sweet spot.

Warmed up engine, at idle. The engine will tell you what it likes.

There is likely a better way to do this but it works for me.

[Cheromaniac]

My highly unscientific process for the dist. based engine is to rotate the dist CW/CCW till you find the sweet spot.

Warmed up engine, at idle. The engine will tell you what it likes.

There is likely a better way to do this but it works for me.

That's the only way I know too.
Slowly turn the dizzy one way until the engine runs like poop. Mark the position.
Then slowly turn the dizzy the other way until the engine runs like poop again. Mark the position.
Then turn the dizzy back and lock it in the middle of the two marks.

[rwkhaussupply]

Well I would expect a more black and white method.

But I will try this in the next few days and see what I yield.

[jeepxj3]

I think that the snap-on 2500 scan tool or the other chyrsler DRB handheld scan tool gives a value for the cam-crank timing and allows you to set the cam pos sensor position and not use the toothpick method.

[Cheromaniac]

Well I would expect a more black and white method.

If you don't have a scan tool, this crude method will at least get you by until you can index it accurately.

[jeepxj3]

I think that if the cam and crank are not synchronized within a certain range as recognized by the ecu, a code will be set.
Using the toothpick method will not work as you advanced the cam 4*, that method is for a stock cam without any additional advance set.

I would set it 'toothpick' method and see if sets a code. If it does set a code, try moving one direction and see if it sets a code. If it does set a code, try moving a small additional amount and re-test for a code. If still sets a code, move the other direction and retest.
The position that doesn't set a code might not be the same position that runs the best. But it will be within the cam-crank parameters.

[SilverXJ]

I think that if the cam and crank are not synchronized within a certain range as recognized by the ecu, a code will be set.
Using the toothpick method will not work as you advanced the cam 4*, that method is for a stock cam without any additional advance set.

Just stop. You don't know what you are talking about.

[jsawduste]

I think that if the cam and crank are not synchronized within a certain range as recognized by the ecu, a code will be set.
Using the toothpick method will not work as you advanced the cam 4*, that method is for a stock cam without any additional advance set.

Just stop. You don't know what you are talking about.

Thank you Chris.
Not to mention Robert makes comment of a dist. rather then an OPA.

[rwkhaussupply]

I think that if the cam and crank are not synchronized within a certain range as recognized by the ecu, a code will be set.
Using the toothpick method will not work as you advanced the cam 4*, that method is for a stock cam without any additional advance set.

Just stop. You don't know what you are talking about.

Thank you Chris.
Not to mention Robert makes comment of a dist. rather then an OPA.

Opa?

[jsawduste]

Oil Pump Drive. My bad.