Engine misfire MDS system failure?

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RamJam53

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I picked up a 2011 Ram 1500 at an internet auction. I have read enough of these posts to realize this is a cronick hemi problem. However there is no tick at all. Even with a stethoscope all I can pick up is the injectors cycling. I went through the whole dance like everyone else with plugs and coils ect. and finally pulled the valve cover. I have noticed that in all the other videos I have seen the valves at least move a small amount but my #1 valve spring (it throws a P0301 code) doesn't move at all.....zero. I was hoping to get lucky and have it be a broken valve spring.... but no. My question is....is it possible for it to be the MDS lifter is bad on the #1 cylinder and won't lift the push rod at all? Like I said there is zero valve movement when cranked. Also when driving it it really bucks when the torque converter locks up under light throttle.......seems like it is more than one cylinder would do......back off and step on it harder and it seems to smooth out? Wondering if this could be a MDS system malfunction. One last thing, and I'm not sure if it is related, when I let off gas like coming off the Interstate and coast to slow down....when I go to pick up the gas again sometimes I have to keep pushing the throttle down to maybe half throttle with no response and then it will catch and take off hard? Hope someone has seen this before TIA
 

Dodge 1500 4X4

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X2 also #1 is not MDS, they are middle cylinders, there's allot of members on here that are a Carnick on the 6 speed trans.
 
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RamJam53

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1,4,6,7 are mds cylinders
That's what I understood too. Haven't researched it enough yet to determine if a lifter failure or lifter MDS control could cause the zero valve lift. Could MDS system failure cause the misfire and lurching when the torque converter locks up at lower RPM's. Does the solenoid close or open to allow the lifter to function? The fact there is no tick at all make me suspicious that it is a bad roller. It acts like the MDS is not functioning correctly like I described at lower RPM's and seems to clear up at higher throttle but still has a misfire at higher RPM's. Where is the MDS controlled at the ECU? Could the throttle issue be connected? Don't really want to tear it down and find out it was a electrical solenoid or ECM control issue.
 
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RamJam53

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Can something like this be diagnosed with a scanner or would that be a waste of money?
 

DILLIGAF

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Pull of the Valve Cover and look
 

Octane

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That's what I understood too. Haven't researched it enough yet to determine if a lifter failure or lifter MDS control could cause the zero valve lift. Could MDS system failure cause the misfire and lurching when the torque converter locks up at lower RPM's. Does the solenoid close or open to allow the lifter to function? The fact there is no tick at all make me suspicious that it is a bad roller. It acts like the MDS is not functioning correctly like I described at lower RPM's and seems to clear up at higher throttle but still has a misfire at higher RPM's. Where is the MDS controlled at the ECU? Could the throttle issue be connected? Don't really want to tear it down and find out it was a electrical solenoid or ECM control issue.
The cam turning has to move the valve; cam/lifter is bad.If what you are describing is accurate.
 
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Octane

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Scanner and teardown?
 
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RamJam53

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Solenoid allows oil pressure to the lifter and without oil pressure there it cant work the lifter properly?
Ok now I have to figure out how to check the solenoid to see if it is working like it is supposed to.
 

Octane

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Ok now I have to figure out how to check the solenoid to see if it is working like it is supposed to.
But if there was no oil pressure getting to that lifter then it would wipe out the cam lobe pretty fast anyway.
 
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RamJam53

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Scanner and teardown?
You know what they charge to scan it? I read one thread where the dealer flashed his TCM (truck was running and driving similar to mine) and the truck ran and drove perfect. can the computer get so far gone it can act like that? Wonder what it cost to have it flashed? Would an aftermarket tune do the same thing?
 
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RamJam53

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I'm tearing off the heads and see whats up. Not what i wanted to do with my spare time right now.
 
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RamJam53

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Can't say I've seen one that looks like this before. The only thing I can think of is the lifter wheel rotated. The lifter wheel doesn't really look that bad considering. The lobe next to it shows wear starting on the lobe and the lifter wheel bearings are worse than the one with trough in it. There are 2 other lifters that were going bad too. Definitely going with the MDS Delete.
 

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msedly

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Mine looked exactly the same when my lifter failed on #1. Roller seized up and the lifter turned 90 degrees.
 
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