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Well, I did what I said I was not going to do. I replaced the MDS harness with a brand new OEM harness and it fixed nothing. The 17 year old harness I replaced looked very good. Back to square one.
 

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I believe the cam, lifters and compression are good but cannot say for certain. I assume these things to be ok since I can manually shift or use tow/haul mode to prevent the problem from occurring. Also, when I let it fail (driving it with transmission in normal mode when the engine is cold) I can fix the issue immediately by resetting the computer. It always fails on cylinder 1, has new MDS solenoids, and I've checked and/or replaced the harness from the ECM to the MDS. With that, the only thing left I can reasonably conclude is that it's the ECM. I should know in about 3 weeks as I just shipped the ECM to get repaired.
 

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Discussion Starter · #64 · (Edited)
I just Installed AlfaOBD on my laptop!! AND wow!! ive been looking for a OBD2 PC program for dodge for years.
With this software i can turn on and off MDS solenoids program keys and much more..
Polaridoo your problem is almost the same, Its cylinder 4 for me, new MDS installed.. harness is good gets stuck then i need to reset computer, but that dont always work the 1st time,
I started this post a long time ago and im determine to get to the root of the problem. With this new program I can definitely dig deeper than ever before.

I can enable and disable individual cylinders but only when the vehicles off. So in my first testing I disengaged and reengaged all 4 solenoids and when I started it up cyl4 was stuck which is odd because the truck was not on when testing and there was no oil pressure so I think this rules out the lifter having mechanical lock pin problems which is what I started worrying was the case.

After playing with it I noticed cylinder 4 when engaged it would sound like the rest and when it disengaged it sounded like the rest but there is a 10 second delay between engaging and disengaging all other cylinders make a ticking noise multiple times between engage and disengage cylinder 4 does not make this ticking noise
So cylinder 4 is not acting the same as the other 3 in the test. It is a AutoZone part and the other three look original. Maybe that's why they sound differently but I feel like that's not the case.

I also discovered there is a relay under the hood that controls the MSD solenoids im going to test to see if its a better way to disable the MDS then pulling the oil sensor plug.

I'm thinking that I bought a defective new MDS solenoid or there is a computer issue.

Polaridoo how much does it cost to have the computer sent out?


video is showing the program and testing cyl1 and cyl4

 

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2017 AWD durango GT 3.6
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Yup, IMO every DIY'er with an FCA vehicle should have alfa OBD. I have both the android and PC version but I prefer the PC version as you can send custom codes which I have used for can bus sniffing.

I have used alfa on my challenger to enable launch control and on my durango I used it for my LED light installs but also to enable the factory tow harness. As a diagnostic tool it is awesome. I've use it to determine which wheel sensor has failed by logging each individual wheel speed (in RPM). Paired with HP tuners and an unlocked PCM you have pretty much dealership level wizardry and then some.
 

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Blazz81- thanks for sharing AlfaOBD and your video; very cool stuff. I wish I would have known about it before but I might be learning about sooner than later if the computer repair place doesn't find anything wrong.

The place I sent my ECM to charges $185 but that is a rough estimate. Once they take apart the ECM, evaluate it, and run tests they will call me with the specifics of what they found and adjust the price accordingly. I will post the results as soon as I hear back from them. Honestly, if it's not the ECM I will be surprised. Just thinking out loud, but what else would cause the MDS solenoid to activate on one cylinder other than the computer? I was very thorough in testing the wiring harness and looking for a bad connection. I think it is very improbable that there is a bad wire next to the MDS wire for cylinder 1 conveniently supplying 12 volts so that cylinder gets shut down. Furthermore, if there was some errant 12 volt supply being applied to cylinder number one, I don't see how putting it in tow / haul mode would prevent that. I think I'm just trying to keep myself optimistic. Honestly, this is a toughest thing I've ever troubleshot. I hope they find a problem in the ECM and can fix it. Stay tuned....
 

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Discussion Starter · #67 · (Edited)
i have 2 Durango's same year 2006 with this problem, one has a problem with cyl4, it runs fine until MDS kicks in. then when its time to kick out of MDS cyl4 wont reactivate unless I shut the truck off and reset computer. unplugging oil sensor keeps it from turning on MDS. i replaced the MDS cyl4 in this truck with no fix.

2nd Durango has a problem with 4 and 7 going by the trouble codes, both cylinders started acting up at the exact same time. with that truck it runs on 6 cylinders from startup. I have to unplug main MDS plug on driver side back of engine.. then it runs fine. as soon as i plug it back in it runs ruff. This one i think it could be the wire. but today i ran the same alfaobd test in my last video and 4 and 7 don't make the ticking sound. i have not changed any MDS on this truck yet.

on both trucks all MDS solenoids in the test make a clunk sound to start and then a buzzing sound for 10 sec then a clunk off sound.
the working MDS solenoids make a taping sound when its buzzing in the 10 sec window, like in my video.

Both trucks run awesome other then this, Even now with MDS disabled/bypassed.

I just read a old 2019 post that AlfaObd can turn off MDS im trying to confirm in another post.
 

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2017 AWD durango GT 3.6
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i have 2 Durango's same year 2006 with this problem, one has a problem with cyl4, it runs fine until MDS kicks in. then when its time to kick out of MDS cyl4 wont reactivate unless I shut the truck off and reset computer. unplugging oil sensor keeps it from turning on MDS. i replaced the MDS cyl4 in this truck with no fix.

2nd Durango has a problem with 4 and 7 going by the trouble codes, both cylinders started acting up at the exact same time. with that truck it runs on 6 cylinders from startup. I have to unplug main MDS plug on driver side back of engine.. then it runs fine. as soon as i plug it back in it runs ruff. This one i think it could be the wire. but today i ran the same alfaobd test in my last video and 4 and 7 don't make the ticking sound. i have not changed any MDS on this truck yet.

on both trucks all MDS solenoids in the test make a clunk sound to start and then a buzzing sound for 10 sec then a clunk off sound.
the working MDS solenoids make a taping sound when its buzzing in the 10 sec window, like in my video.

Both trucks run awesome other then this, Even now with MDS disabled/bypassed.

I just read a old 2019 post that AlfaObd can turn off MDS im trying to confirm in another post.
Uploading my answer to that post here.

BTW I wonder if the lock pin on the lifter has engagement/release issues once the solenoid is deactivated to remove pressure acting on the pin.
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Discussion Starter · #69 ·
BTW I wonder if the lock pin on the lifter has engagement/release issues once the solenoid is deactivated to remove pressure acting on the pin.
View attachment 122343
I started thinking the same thing about the pin. but when i tested the MDS with truck off and no oil pressure it was stuck on when i started after the test, I would think without oil pressure the pin would not activate.
at the time MDS was bypassed for over 6 months and has not activated at all till i did the AlfaObd MDS test on cyl4.

Here is a picture i posted a few pages ago, you can see the computer shows cyl4 MDS is activate and cyl4 injector is off. but other cylinders are normal.
Also a video of cyl4 valve but i cant say for sure if MDS was stuck at the time i took it apart and made video.

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