Looking for CAM/Crank sensor Waveform for 2005 Wrangler 4.0 - JeepForum.com
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post #1 of 17 Old 06-09-2021, 12:43 PM Thread Starter
ltklein
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Looking for CAM/Crank sensor Waveform for 2005 Wrangler 4.0

I'm working on a P0344 issue with my 05 Rubi LJ. Jeep runs but it goes in limp home mode after 30-60 minutes - not related to temperature.


Have a lot of work done based on threads here and elsewhere - bypassed the harness, new CPS, new OPDA (cuz it should have a new one after 162,000 miles anyway).


Before we get into real-money (ECU, new camshaft) , I just need to verify the CAM sensor relationship as it goes into the ECU.



Have a solid CAM signal going into the ECU when it flips the code so it's either:


a) not recognizing a good signal when it sees it
b) getting an out of time signal
c) wear/slop in the timing chain or cam gear driving the OPDA is drifting outside of the limits.


This has been in the dealer once (I was on a road trip to Death Valley when this struck). They were confident in clipping my wires and bypassing the wire harness.



It failed 32 miles out of town and I limped it home a few hundred miles. I put in a new CPS and it still tripped. Then it went to the dealer.


At home I put in a new OPDA, correctly timed per the FSM. Then I put in a new crank position sensor as some here have seen that interaction. They all share the same 5volt buss and ground after all.



The one thing I can't do at home is a cam/crank relearn and the dealer charges me $125 just to hook up to my Jeep.


I have an automotive oscilloscope and a CAM/CRANK sensor trace. I want a known good reference to see if the relationship is correct.


Anyone have one available? This is unique to 2005 and 2006 Wrangler 4.0 engines.


Mine is copied below.


Thanks!


Before I pay them a visit, I want to make sure everything outside of the ECU is correct.

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post #2 of 17 Old 06-09-2021, 04:16 PM
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Here is info that may be helpful. It is a bit dated but good info. The only update I can think of is that for some time now even the cam sensors from the dealers are giving the same problems so I suspect they are using the same supplier as everyone else is.

Also note that the P0344/340 issues has been proven (to me with a ton of data saying so) to be a sensor, possible bad air gap related too, issue. Not a cam/crank sync or PCM or wiring issue. I know for sure more than 1 member has replaced their PCMs (dealer advised) with no improvement.

I wish I could contact psouza who did the work in the link. So far no luck.


https://www.wranglerforum.com/thread...sensor.914394/ post #14

https://www.jeepforum.com/forum/f9/20...l#post15520973 posts #4580 then #4951 & 52 for the meat of this with the scope patterns.

https://www.jeepforum.com/forum/f9/ne...l#post24009538
post #401

https://www.jeepforum.com/forum/f9/od...l#post34707545
post #23

I think that is everything I have from him.
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post #3 of 17 Old 06-09-2021, 05:47 PM Thread Starter
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Fantastic response...thank you!


I wasn't able to download the PDF in Post 4951 - it keeps taking me to a Vbulletin link telling me I already created an account in my name. I'll try later in case the forum the wires crossed.


I did come across threads suggesting there are no reliable sources of new cam sensors. I think I'll put in the 3 I have and check the waveforms against each other. I still have the original, a Duralast and a Crown.


I also note that some folks have shimmed their sensors out with washers. Looks like I have a lot of hocus pocus in front of me!..


Again...Thank you very much!
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post #4 of 17 Old 06-09-2021, 06:11 PM
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If I recall the PDF was in 4951 & the actual shot was in 4952. I think he made some reference to some not being able to open it so he posted it. If you don’t find it there let me know & I will copy it here.

As for shimming, yes, that is a crap shoot but did work for one or two members that did follow up posts. Of course they might have had the code reappear the next day too. As I said mixed, mostly bad, results. It is easy to shim it out, 1 guy used aluminum foil others used thin washers. The hard part is closing the gap. You need to do some grinding on the sensor. What I found interesting is various guys reported their gaps & they were all over the place. Some closer than my 0.021”, others a lot more. That is simply bad tolerances in the casting/machining process when making the housing or where they place the hole for the bushings. Then you have low quality sensors & no chance for a good outcome.

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post #5 of 17 Old 06-09-2021, 07:46 PM
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A clarification:

I have been looking at the scope shots of both sensors which I have not done in a long time. I see that it is not that the 5v pulse is too short on the aftermarket sensor it is to 0v pulse (dwell) that is too short. Either way, I would think the PCM is unable to read the non standard signal it is seeing from aftermarket & now the later dealer supplied ones as well.
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post #6 of 17 Old 06-10-2021, 03:45 PM Thread Starter
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With my 3 sensors, I'm set up to repeat those results so that's this weekends endeavor. I have OEM, Duralast and Crown. The last 2 being new.


A wider dwell or pulse may still work fine if its perfectly timed to the last time it was resynched -- as long as the ECU is doing mid-pulse sampling. That may be exactly what the resynch does - finds the center of the CAM and Crank pulses and then synchs those readings.. Don't know for sure but makes sense. But it can make it harder to hit that sweet spot tweaking the OPDA manually, especially on a high mileage engine which may have timing chain or cam gear slop.

I'll post up those waveforms and add to the collective knowledge on the pulse-width subject.

On the post 4951/52 - yeah...I can't see the shot in 4952 either. If it's convenient and you can repost here, I certainly would appreciate it!


Job is interfering with my troubleshooting time!
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post #7 of 17 Old 06-10-2021, 04:36 PM
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In the links I posted he mentioned have it throw codes above a certain which I havenít seen posted in the various 340/344 postings but thinking about that combined with a short dwell makes me thing maybe the PCM canít process the data that fast. Maybe even to the point with some (really bad) sensors even at idle is too fast???

I have been relearning some of this since it has been a long time since I read through everything I have on this subject. There is definitely a cam/crank sync relationship but have always assumed if you were not getting the P0016 sync code you were within the necessary tolerance but that assumes, of course, it is relative to the PCM ability to process the expected data. So you might be onto something about relearning/syncing. I just read (reread) an article that had the conclusion that you might have to time them with a scope rather than a timing light. I will post just the conclusion.

And here is the screen shot from the 4952 link.
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post #8 of 17 Old 06-11-2021, 09:23 AM Thread Starter
ltklein
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That last shot is what I was struggling to come up with - thank you!


I did have a P0016 once...and that was following the long limp from Death Valley to Wikiup, AZ where it started dying instead of just being in limp home mode. Having another 90 miles of desert to cross with no cell service to get roadside, I left it there, caught a ride home and tow barred it home.


That code hasn't returned but I haven't run it as long. Also had a MAF code and I replaced that with the hopes maybe it was shorting. Fixed the MAF code but I suspect it was unrelated to the overall issue.


I'll be on the edge to see if P0016 returns over time. I can get the P0344 to come up in a short-ish run.



Thanks again for reposting those...I don't know why my browser wasn't showing them. Another thing to troubleshoot!
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post #9 of 17 Old 06-11-2021, 09:30 AM Thread Starter
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Shucks...sooo close. I can see the crank signal on that trace is different than mine...I don't have 4 repeating pulses. I have 15 - I think that's what I counted. But I'm looking to mimic that process exactly.


As part of the weekend festivities (115 degrees this weekend so it will be short)...I'm going to mark, then turn my OPDA slightly and watch my scope and see if I can find a sweet spot. If I'm lucky, I can make it pop a P0016 in both directions and then put it in the middle.



Now I'm inventing my own troubleshooting....


I have the pin from the installation so I can repeat the TDC process...
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post #10 of 17 Old 06-11-2021, 11:35 AM
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The P0016 can come up from wear on either the timing chain/sprockets or wear/stretch or the cam/OPDA gears. The chain/sprockets is more “normal” wear. Either will retard the cam timing relative to the crank. Eventually is may exceed the tolerance limit & set the code. I always recommend when installing an OPDA to set in to TDC then install with the pin rather than just set the old one to pin alignment (not looking for TDC), then the new one. That way you are compensating for any wear & getting it back (as close as possible) to proper sync with the crank.

I see you mentioned stopping at a dealer on your DV trip. Where was that? Or is that in Wikiup?

I know about no cell service. Having been to DV several times I can say there is no service there. And leaving going south through CA you don’t get service until over the last pass about 40 miles from Baker. It is not nearly as far going east into NV.

Back on topic.

I did notice the many crank pulses you showed which is odd since the flywheel has 3 sets of 4 notches. I count 15, 16, & 15 pulses in the view you posted but looking closely it looks like every other one is actually a wide pulse rather then a dwell to the next & the only dwell is at the 3 pulse cam signal. Not sure what that is all about. Any ideas?? Maybe play with that when scoping it again. It seems that besides expecting 4 pulses there would be dwell (no signal) at each of the cam signal spots. Also try looking at patterns at various RPM levels since psousa did note RPMs as a factor.

Just to clarify, the last shot I posted is from an earlier jeep that only had 1 180į pulse from the cam sensor. We have the 1, 2 & 3 notches on our OPDAs so not sure where it should line up with the crank but it appears it is the 3 notch sequence that triggers off the crank (in your posted shot) & needs to be synced with the dwel (flat spot) of the crank signal. Yours looks to be centered which might be correct or maybe to needs to be at the beginning or end, then is it using the beginning, center or end of the 3 pulses. That is what I do not know. I wish the psousa screen shots would have had the crank signal included to compare. He was not trying to get sync so I understand not having it but it would be helpful for us to have. I do understand the 1, 2 , 3, 2, 1, 3 arrangement but am a little surprised they would not trigger off the single pulse, it would be easier to know where the PCM sees it as the trigger point.

It certainly will be interesting what you see & what happens as you turn the OPDA. Post screen shots of anything interesting that you get.

Try to stay cool.
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post #11 of 17 Old 06-11-2021, 01:41 PM
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Nice to see the scope shots, I'd hate to have to use a scope to get my TJ running correctly. I spent years using various scopes in my earlier RF and computer jobs, they're great help but man vehicles are just getting crazy complex when you have to resort to a scope. Good luck with this!!!

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post #12 of 17 Old 06-11-2021, 04:36 PM Thread Starter
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I used the dealer in Pahrump. I was 30 miles out from there when this "adventure" started and was going to be in Pahrump for 1 night and the rest of the week in Beatty. Had to wait a day for the sensor to come into Autozone so did 2 nights in Pahrump. When that didn't solve it, I was thinking I'm 700 miles from home...so take it to the dealer and make what I can of the vacation.

They couldn't get it in until the end of my trip so they had it for only 2 days and I had to start home with it.

I'm sure they would have worked with it if I could have brought it back so I'm not inclined to give them grief. Intermittent problems are the hardest to solve.

Regarding the Crank pulses...ya made me look. Just pulled up a picture of the 05 flywheel and it matches what we're seeing - 16 then high and 16 then low (or was it 15?)...

Getting up early tomorrow to test... more to follow...
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post #13 of 17 Old 06-11-2021, 04:38 PM Thread Starter
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Oh...and that flywheel pic...
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post #14 of 17 Old 06-11-2021, 06:39 PM
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It's easy to see why you're getting a 15-low-16-high signal when you look at an '05/'06 flywheel versus the previous version used up through '04 that had three sets of four notches. The changeover to an NGC PCM brought with it not only the rather hated large tone ring type cam sensor OPDA with its multiple notches, but also a unique matching flywheel with many more notches. Unfortunately even the FSM for '05 and '06 doesn't have an example of the correct signal waveform for these late model 4.0L TJs, they only show the waveforms for the earlier 4.0L, 2.5L, and 2.4L engines.
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post #15 of 17 Old 06-11-2021, 07:24 PM
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Thanks mukluk.

It’s interesting about the flywheel. I guess they only really need one spot marking the 1/6 TDC to sync the cam, then use the 6 OPDA sets of notches to better sync & trigger the injectors which is probably one reason they went to this setup. They also did want to standardize everything in the (Chrysler) line with the NGC PCMs.
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