OPDA TDC reset

BoldlyGoing

BoldlyGoing

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I swapped my OPDA this morning suspecting it was the source of my squealing/grinding (it wasn’t but that’s another discussion).

So, I disconnected the battery, followed the “align the pin hole” procedure, swapped it, and reassembled everything.

On the test run, engine runs fine, but I’ve got a P0016 code. First thing I’ve done is tried swapping the OEM Crankshaft Position sensor back in instead of the one that came with the crown unit. Code remains.

So, clearly something is out of sync. Before I go through the trouble of pulling serpentine belts and plugs and verifying TDC, is there anything else I can try?
 
mots said:
@Daryl posted some info from the FSM on this in another thread. Read about my experience here with P0016. If you know how the housing was orientated at TDC, get it back close to there and the code will go away.
https://wranglertjforum.com/threads/mots-2005-x-rocky-mountain-edition-oem-build.12446/post-244634
Click to expand...

As far as I can tell, it’s oriented the same way the old one was. My understanding though is that the Sensor only allows for ~15° of variance.

There’s at least that much play in the unit before you clamp it down, so I may try fiddling with that a bit.
 
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Got any pics of the engine bay before you removed it so you can compare? If you loosen the lock nut a bit you can rotate the housing quite a bit. I had to rotate mine 5 degrees or so and then the code stopped popping. If you started at TDC before you removed it, this should be your issue.
 
mots said:
Got any pics of the engine bay before you removed it so you can compare? If you loosen the lock nut a bit you can rotate the housing quite a bit. I had to rotate mine 5 degrees or so and then the code stopped popping. If you started at TDC before you removed it, this should be your issue.
Click to expand...

If aligning the holes and inserting the pin prior to removal reliably establishes TDC, then yeah.

I’m gonna turn it a bit it now and see if that fixes it. Annoyingly, I didn’t pick up on how critical aligning the housing was, so I didn’t bother with any “before” pics, but going from memory, it’s close.

We shall see.
 
BoldlyGoing said:
If aligning the holes and inserting the pin prior to removal reliably establishes TDC, then yeah.

I’m gonna turn it a bit it now and see if that fixes it. Annoyingly, I didn’t pick up on how critical aligning the housing was, so I didn’t bother with any “before” pics, but going from memory, it’s close.

We shall see.
Click to expand...
Yep, you should be good then. It’s just that the housing is not close enough in orientation to how it was before. I’d also switch back to the Mopar sensor if you haven’t.
 
mots said:
Yep, you should be good then. It’s just that the housing is not close enough in orientation to how it was before. I’d also switch back to the Mopar sensor if you haven’t.
Click to expand...

I did swap back to the MOPAR sensor.

I rotated it a bit (there is a lot more available play than I thought) so this may take a little while. First attempt still popped the code.

I know the sensor pointed roughly toward the front of the Jeep, so I may start there and rotate clockwise until the code stops popping.
 
BoldlyGoing said:
Ok. So this was less painful than I expected.

After generating some new and exotic CEL codes, the code isn’t coming back. Going to let it run a little while and see if anything pops, but I’m gonna cautiously call this fixed.
Click to expand...
.

I been having the same issues for 6 months now. No one close to my area seems to know the fix. can you please take a picture of how the OPDA ended up so that I can use it for reference?
 
robsam said:
.

I been having the same issues for 6 months now. No one close to my area seems to know the fix. can you please take a picture of how the OPDA ended up so that I can use it for reference?
Click to expand...
I can, but I doubt it will be much help.

What I did was pull the battery cable-
Point the sensor connection directly toward the front of the Jeep.
Put the cable back on, start the Jeep.

I’d let it run till the code popped.

Then I’d disconnect the battery and turn it slightly in a clockwise direction.

Repeat until the code stopped coming up.

It probably won’t start at all for the first couple attempts. Then as you get closer and closer, it will start, but run like shit.

Then it starts to settle, then you’ll land in the sweet spot.
 
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BoldlyGoing said:
I can, but I doubt it will be much help.

What I did was pull the battery cable-
Point the sensor connection directly toward the front of the Jeep.
Put the cable back on, start the Jeep.

I’d let it run till the code popped.

Then I’d disconnect the battery and turn it slightly in a clockwise direction.

Repeat until the code stopped coming up.

It probably won’t start at all for the first couple attempts. Then as you get closer and closer, it will start, but run like shit.

Then it starts to settle, then you’ll land in the sweet spot.
Click to expand...
I hope this works. I installed the OPDA last week and all was fine, till I realized I didn’t install the tiny gasket and was losing oil. So I pulled it and slid it right back in. Now it won’t start. Housing must be slightly off. Arghhhhh....
 
JMT said:
I hope this works. I installed the OPDA last week and all was fine, till I realized I didn’t install the tiny gasket and was losing oil. So I pulled it and slid it right back in. Now it won’t start. Housing must be slightly off. Arghhhhh....
Click to expand...

Cool, I see you are being told essentially the same thing here :) This method should work. You may be able to get the starting position a bit closer by looking at pics you may have of your engine bay. I'd start with the two OPDA cover bolts and visualize an imaginary line with them and make that line parallel with the valve cover line. Then rotate clockwise from there until the P016 code stops popping. I think it will at least start at this beginning position.

This one has been rotated to its final sweet spot. It has been turned clockwise a few degrees from the imaginary parallel lines making them no longer parallel.

80975
 
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mots said:
Cool, I see you are being told essentially the same thing here :) This method should work. You may be able to get the starting position a bit closer by looking at pics you may have of your engine bay. I'd start with the two OPDA cover bolts and visualize an imaginary line with them and make that line parallel with the valve cover line. Then rotate clockwise from there until the P016 code stops popping. I think it will at least start at this beginning position.

This one has been rotated to its final sweet spot. It has been turned clockwise a few degrees from the imaginary parallel lines making them no longer parallel.

View attachment 80975
Click to expand...
I must have the OPDA slipped in one notch clockwise of the right position because mine is much more counter clockwise than that now where it is rough starting and throwing codes (but the best spot), whereas before it looked more like the photo above.

Think I could slip the OPDA out again and rotate slightly counter clockwise and re-try?

EDIT: sorry, I had to edit a clockwise to read counterclockwise so my post is not confusing. Here’s a pic of where it is now and starts.
80976
 
Last edited:
JMT said:
I must have the OPDA slipped in one notch clockwise if the right position because mine is much more clockwise than that now where it is rough starting and throwing codes (but the best spot), whereas before it looked more like the photo above.

Think I could slip the OPDA out again and rotate slightly counter clockwise and re-try?
Click to expand...

It's shouldn't be the OPDA shaft, that will only spin on and slide down and mount cleanly to the block in one way (as the OPDA gear it slides into the camshaft gear). I'm pretty sure you can't get that part wrong. It is the OPDA housing that you turn by hand while the OPDA is already mounted and parked on the camshaft gear. That is what is changing the timing. If you lock down the OPDA retainer clip with the housing spun off its proper position, this is where the problem starts.
 
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The proper and efficient way is pinning both OPDA'S , the OEM during removal by turning the engine pulley clockwise until pin drops.
Then orientate the Crown OPDA the same way with pin or screwdriver during installation.

The pin is not to be removed until OPDA is seated firmly in place by twisting counterclockwise and drops exactly in place where OEM was.....replaced mine and 2 others without issue.
80985

80981

You can see the small alignment hole.
80983
 
I can't recall the " play " that's being referred too as the gears on the OPDA and Cam work together to snug things up.
 
mots said:
It's shouldn't be the OPDA shaft, that will only spin on and slide down and mount cleanly to the block in one way (as the OPDA gear it slides into the camshaft gear). I'm pretty sure you can't get that part wrong. It is the OPDA housing that you turn by hand while the OPDA is already mounted and parked on the camshaft gear. That is what is changing the timing. If you lock down the OPDA retainer clip with the housing spun off its proper position, this is where the problem starts.
Click to expand...
Alright, after about 100 attempts of getting it just right I said screw it. Went to the research. First, and this is more info on this forum for the OPDA. I went to the FSM as per @Chris recommendation and another unnamed forum with posts from a few knowns over here like @mrblaine. . You have to have the harmonic vibration pulley at Top Dead Center. There is no scale as the FSM says, it’s a metal point that sticks out and there is a notchbyou have to align with that point as pictured below. You’ll need to loosen the belt to see it align.
81071

Once you do that. Reset your OPDA where the two holes align and reinstall. If you need to, rotate the cam shaft with a screwdriver so the OPDA will fall in. Put your bracket back on and remove the pin and crank it. After 4 hours it’s sufficient to say I was elated that I didn’t get anymore p0016 or p0344 or p0522 codes thrown.

Now, to avoid all this, don’t forget to put the fmfamn gasket on when you first install your new OPDA, because you may screw it up when you go back and slip it on, even if you just barely pull it out to get it on
 
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You can also view the timing marks from underneath the Jeep with a mirror if you don't want to remove the belt.

I'm really surprised how many people are giving advice based on the orientation of the OPDA housing to the motor or other components external to the OPDA. None of that matters a lick. The orientation that matters is the relationship between the rotating disk in the OPDA and the OPDA housing when the motor is at TDC compression on #1.

Bird's procedure works if and only if the OPDA you remove happens to be timed correctly AND the wear on the OPDA gear is not that bad. If it is timed correctly, the holes will only line up if the motor is at TDC on #1 compression. However, many OPDA's that are getting replaced have significant wear on the gear so that the timing is not that precise. And in many cases the timing has been F'd with and it's therefore not timed correctly to start with.

Do it right once and be done.

You definitely want to at least keep and probably use the original sensor from you old OPDA.
 
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