Interesting OPDA findings

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Bill M.

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Looking for a couple of 2005/2006 original Mopar OPDA any condition.

The back story is that after a long search for a new Mopar CMP sensor to install in a Crown OPDA we found one last week. Installed it the Crown OPDA and it would not create a signal, bummer. So took the OPDA and a handful of different manufacturers sensors over to friend shop that had a distributor machine. We got the Crown OPDA and Mopar sensor to work but not in the standard Crown configuration. Several of the other sensors worked but not consistently.

Now what we would like to do is compare the stock original OPDA from Mopar to the Crown OPDA to compare specs. Problem is we throw away all our old Mopar OPDAs. Thus we are looking for your help to find a couple of old OPDA. Once we compare the specs we will publish our finding here.
 
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I have one you can have for $10 shipped. PM me your full name and shipping address. I'll get it out on Thursday.
 
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Chris, after lots of testing of cam position sensors (CPS) and OPDA's we found that the Crown OPDA is the best out there. To beware of the Mopar and Dorman OPDA.

When come to cam position sensor we tested Crown, Standard, Mopar, Napa, Dorman and some brown bag ones from Ebay. Some were units that had been replaced because they were "bad" some were brand new but the only one that was actually bad was the Mopar original from the dealership, go figure.

What we found was that the after market CPS generally had about 3 degrees more drop down dwell than the Mopar CPS. Thus cam to crank sync with the aftermarket CPS was almost always out of tolerance when installed. After we synced each sensor and ran the factory CPS relearn procedure all the sensors worked fine except the one bad Mopar.

The factory PCM only allows a cam to crank sensor out of sync tolerance of 1.2 degrees +/- at the cam before it goes into limp mode. Because the Mopar drop out dwell is 4 deg. and the Crown, as an example is 7 deg., when a TJ owner replaces the Mopar CPS with the aftermarket CPS without regard to whether they are replacing OPDA and align the OPDA exactly like the old OPDA they are already out of tolerance. Thus requiring that the cam and crank sensors be resynced and then the relearn performed.

The problem is that most scan tools, even the expensive ones like Snap-on, don't have the factory relearn procedure. They can do the sync procedure but not the relearn. The sync must be done first and then the relearn to guarantee reliable results. We used a Zurick ZRPRO, DBR2 and Hantec 1008c for testing.

Hope that helps.
 
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Bill M. said:
Chris, after lots of testing of cam position sensors (CPS) and OPDA's we found that the Crown OPDA is the best out there. To beware of the Mopar and Dorman OPDA.

When come to cam position sensor we tested Crown, Standard, Mopar, Napa, Dorman and some brown bag ones from Ebay. Some were units that had been replaced because they were "bad" some were brand new but the only one that was actually bad was the Mopar original from the dealership, go figure.

What we found was that the after market CPS generally had about 3 degrees more drop down dwell than the Mopar CPS. Thus cam to crank sync with the aftermarket CPS was almost always out of tolerance when installed. After we synced each sensor and ran the factory CPS relearn procedure all the sensors worked fine except the one bad Mopar.

The factory PCM only allows a cam to crank sensor out of sync tolerance of 1.2 degrees +/- at the cam before it goes into limp mode. Because the Mopar drop out dwell is 4 deg. and the Crown, as an example is 7 deg., when a TJ owner replaces the Mopar CPS with the aftermarket CPS without regard to whether they are replacing OPDA and align the OPDA exactly like the old OPDA they are already out of tolerance. Thus requiring that the cam and crank sensors be resynced and then the relearn performed.

The problem is that most scan tools, even the expensive ones like Snap-on, don't have the factory relearn procedure. They can do the sync procedure but not the relearn. The sync must be done first and then the relearn to guarantee reliable results. We used a Zurick ZRPRO, DBR2 and Hantec 1008c for testing.

Hope that helps.
Click to expand...

Sounds like that confirms using the Mopar sensor with the crown opda is best?
 
Bill M. said:
Chris, after lots of testing of cam position sensors (CPS) and OPDA's we found that the Crown OPDA is the best out there. To beware of the Mopar and Dorman OPDA.

When come to cam position sensor we tested Crown, Standard, Mopar, Napa, Dorman and some brown bag ones from Ebay. Some were units that had been replaced because they were "bad" some were brand new but the only one that was actually bad was the Mopar original from the dealership, go figure.

What we found was that the after market CPS generally had about 3 degrees more drop down dwell than the Mopar CPS. Thus cam to crank sync with the aftermarket CPS was almost always out of tolerance when installed. After we synced each sensor and ran the factory CPS relearn procedure all the sensors worked fine except the one bad Mopar.

The factory PCM only allows a cam to crank sensor out of sync tolerance of 1.2 degrees +/- at the cam before it goes into limp mode. Because the Mopar drop out dwell is 4 deg. and the Crown, as an example is 7 deg., when a TJ owner replaces the Mopar CPS with the aftermarket CPS without regard to whether they are replacing OPDA and align the OPDA exactly like the old OPDA they are already out of tolerance. Thus requiring that the cam and crank sensors be resynced and then the relearn performed.

The problem is that most scan tools, even the expensive ones like Snap-on, don't have the factory relearn procedure. They can do the sync procedure but not the relearn. The sync must be done first and then the relearn to guarantee reliable results. We used a Zurick ZRPRO, DBR2 and Hantec 1008c for testing.

Hope that helps.
Click to expand...

So from my understanding, you can make an aftermarket CPS work with a Crown (or Mopar) OPDA, but you need a special tool to sync, then re-learn?

To be totally honest, I had no idea any of this was necessary. Everyone I know has just been dropping in the new Crown OPDA, putting in a Mopar CPS, and calling it good. Most never have issues either.

So there's an entire sync and re-learn procedure I'm not even aware of? Is this specified in the FSM? If so, clearly I need to read it.

Are you saying you can make an aftermarket CPS unit work with any OPDA?
 
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Chris said:
So from my understanding, you can make an aftermarket CPS work with a Crown (or Mopar) OPDA, but you need a special tool to sync, then re-learn?

To be totally honest, I had no idea any of this was necessary. Everyone I know has just been dropping in the new Crown OPDA, putting in a Mopar CPS, and calling it good. Most never have issues either.

So there's an entire sync and re-learn procedure I'm not even aware of? Is this specified in the FSM? If so, clearly I need to read it.

Are you saying you can make an aftermarket CPS unit work with any OPDA?
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Yes it is specified in the FSM after changing the cam/crank sensors or OPDA. We had to buy a new scan tool just to run the test per the FSM. Our Snap-on could not do the relearn.
 
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Chris said:
So from my understanding, you can make an aftermarket CPS work with a Crown (or Mopar) OPDA, but you need a special tool to sync, then re-learn?

To be totally honest, I had no idea any of this was necessary. Everyone I know has just been dropping in the new Crown OPDA, putting in a Mopar CPS, and calling it good. Most never have issues either.

So there's an entire sync and re-learn procedure I'm not even aware of? Is this specified in the FSM? If so, clearly I need to read it.

Are you saying you can make an aftermarket CPS unit work with any OPDA?
Click to expand...

Ive read that yes, you need to tell the PCM to learn the new one.Though I don’t know if that’s just a battery disconnect for a while or an intentional sequence that must be performed. Honestly it confused me a while as my replacement CPS would only ever throw codes (I still have my whatever CPS and just accept in cold weather it complains until warm).
 
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rasband said:
Ive read that yes, you need to tell the PCM to learn the new one.Though I don’t know if that’s just a battery disconnect for a while or an intentional sequence that must be performed. Honestly it confused me a while as my replacement CPS would only ever throw codes (I still have my whatever CPS and just accept in cold weather it complains until warm).
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Don't be confused, the PCM has many learned functions that can not be erased with just a battery disconnect. A battery disconnect does nothing more than a scan tool does when you hit the erase button.

The symptoms you describe in relation to your CPS not working when it is cold is likely because your CPS to crank is out of sync. We have found that the CPS timing between a cold engine and warn engine can vary as much as 1.5 degrees of cam timing. So as you engine warns you CPS to crank sync may very well change enough for the PCM to accept the CPS signal as good.
 
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Bill M. said:
Don't be confused, the PCM has many learned functions that can not be erased with just a battery disconnect. A battery disconnect does nothing more than a scan tool does when you hit the erase button.

The symptoms you describe in relation to your CPS not working when it is cold is likely because your CPS to crank is out of sync. We have found that the CPS timing between a cold engine and warn engine can vary as much as 1.5 degrees of cam timing. So as you engine warns you CPS to crank sync may very well change enough for the PCM to accept the CPS signal as good.
Click to expand...

Fortunately I only ever see this when it sits out in extreme cold overnight. Last year I spent a lot of time on the OPDA orientation - which I think is right, but hard to know it’s not unless I see a code.
 
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Chris said:
So from my understanding, you can make an aftermarket CPS work with a Crown (or Mopar) OPDA, but you need a special tool to sync, then re-learn?

To be totally honest, I had no idea any of this was necessary. Everyone I know has just been dropping in the new Crown OPDA, putting in a Mopar CPS, and calling it good. Most never have issues either.

So there's an entire sync and re-learn procedure I'm not even aware of? Is this specified in the FSM? If so, clearly I need to read it.

Are you saying you can make an aftermarket CPS unit work with any OPDA?
Click to expand...
Most of them are just lucky and get it within tolerable range and it runs. So, they tell everyone since they did it, everyone else can to. We always reset the timing of the unit with a DRB and do the forced relearn. Not one of them put in with even very careful marking and care about orientation is even close to being in spec.
 
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Bill M. said:
Don't be confused, the PCM has many learned functions that can not be erased with just a battery disconnect. A battery disconnect does nothing more than a scan tool does when you hit the erase button.

The symptoms you describe in relation to your CPS not working when it is cold is likely because your CPS to crank is out of sync. We have found that the CPS timing between a cold engine and warn engine can vary as much as 1.5 degrees of cam timing. So as you engine warns you CPS to crank sync may very well change enough for the PCM to accept the CPS signal as good.
Click to expand...
We ran into one similar with the camshaft synchronizer. It would run perfectly up the hill to the mountains and start running like crap coming back down. Friends and shops had the owner replace the PCM, cats, plugs, coil rail, etc. all with no change. I got the call after everyone else had spent lots of the owner's money. I suspected wear on the drive gear was letting it move out of synch slightly going down hill. Put the DRB on it, set it back to 0, all the problems went away.
 
mrblaine said:
Most of them are just lucky and get it within tolerable range and it runs. So, they tell everyone since they did it, everyone else can to. We always reset the timing of the unit with a DRB and do the forced relearn. Not one of them put in with even very careful marking and care about orientation is even close to being in spec.
Click to expand...

Have you managed to make an aftermarket CPS work without any codes being thrown?

I ask because it would seem that factory Mopar units are close to being dried up in terms of stock.
 
Chris said:
So from my understanding, you can make an aftermarket CPS work with a Crown (or Mopar) OPDA, but you need a special tool to sync, then re-learn?

To be totally honest, I had no idea any of this was necessary. Everyone I know has just been dropping in the new Crown OPDA, putting in a Mopar CPS, and calling it good. Most never have issues either.

So there's an entire sync and re-learn procedure I'm not even aware of? Is this specified in the FSM? If so, clearly I need to read it.

Are you saying you can make an aftermarket CPS unit work with any OPDA?
Click to expand...
Chris, refer to the Service Manual section 8I pages 9-13 where you will find the OPDA/CPS replacement procedure. The last step to replacement is "Gain access the "CAM/CRANK RELEARN". The relearn function is done via the factory DRBIII scan tool or equal. First you use the scope function to align the CPS/CKP signals and then push the learn button.
 
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