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Discussion Starter · #1 ·
2012 Ram 1500, 66k, 5.7, vararam/magnaflow catback/tuned.

Hey, all. I appreciate all the info on these forums, and have been having trouble finding more info about some issues with the Ram.

Normal daily driving doesn't come with any issues, but when I "get on it" with some above-average acceleration, I'm getting some kind of failure/misfire. At first I thought it was a transmission issue, since it sounded like the truck was downshifting before taking off. The truck would start accelerating normally, then let out a "WAAAAAAAAAATTT" without accelerating, then after a few seconds something would kick in, and the and the truck will take off. Took it to the dealer (right before warranty expired) and he said tranny was fine, but I needed to change my plugs. Plugs are changed, but the problem persists. While I was at the dealer, I had the exhaust manifold repaired, and haven't had any ticking.

To me, this means coil packs are bad, but I don't want to rule out lifter failure. I'd rather not replace good coil packs, and still have the issue.

about 70% of the time use the "shift to 6th" trick to knock out the MDS. Although, I've experienced the issue whether MDS is active or not.
 

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2014 345ci 8hp70 44-44 3.92 Truetrac NX Express Comp Greene Racing
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Coil packs can usually be tested with an ohm meter and will have a tolerance. You'd have to find a troubleshooting manual as I don't know that info off hand.

You probably don't want to hear this and I hope it isn't true, but coil packs typically misfire at idle/cruise rpm due to lower voltages and not vice versa.

A cam/lifter issue is just the opposite, it might seem fine under low/medium loads but as soon as you want big horsepower the timing and efficiency shits the bed.
 

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Discussion Starter · #3 ·
Coil packs can usually be tested with an ohm meter and will have a tolerance. You'd have to find a troubleshooting manual as I don't know that info off hand.

You probably don't want to hear this and I hope it isn't true, but coil packs typically misfire at idle/cruise rpm due to lower voltages and not vice versa.

A cam/lifter issue is just the opposite, it might seem fine under low/medium loads but as soon as you want big horsepower the timing and efficiency shits the bed.
Yeah, I was clinging to the hope that it was only a power issue (no ticking) I would be good. Any recommendation on testing for a bad lifter?
 

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Discussion Starter · #4 ·
Should also mention the CEL is not on, and inspection didn't show any codes (granted I don't think they pulled the history)
 

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vararam/magnaflow catback/tuned.
I would give your tuner a call, this sounds like an MDS issue. Your tuner would be able to help you rule out if this is an issue with their programming or some kind of mechanical problem.

it sounded like the truck was downshifting before taking of
Were you around 2-3k RPMs when this happened? Sudden engagement of MDS at "high" rpms (the highest rpm stock programming will engage mds is 3k) will make a weird WAAAAAAAT sound, and is especially noticeable if you have aftermarket exhaust. With stock exhaust its like a deep dull jake-brakeish BUUUUR sound. I can PM you a video of the sound if you'd like - I can kinda force my truck to engage MDS at weird points.

That weird feeling that "something kicks in" would be the sudden torque spike when MDS disengages and reactivates the 4 disabled cylinders.
 

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Yeah, I was clinging to the hope that it was only a power issue (no ticking) I would be good. Any recommendation on testing for a bad lifter?
Not that you have a bad lifter, but in another thread it was suggested to pull the valve cover(s) and with the engine running look for a valve operating differently than the others.
 

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If its actually a misfire you should be getting a P03XX code and a CEL. I think its something else here.


Unless you're letting up on the throttle a little I'm not sure how it could be MDS, but the fact you have a tuner introduces some other variables
 

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Discussion Starter · #8 ·
Thanks all. It definitely FEELS like MDS, but still does it when the MDS is deactivated (via shifting to 6th), though worse when I don't do the workaround

The truck came to me tuned (which the dealer told me after owning it for a year, when they went to do a software upgrade). I don't have access to the handheld tuner, or the tuner-person. Seems best bet may be to flash back to stock, and see if the problem persists?
 

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I'd have it flashed back to stock. Theres no guarantee any function would work they way its supposed to unless its stock. I'm almost positive this is either an error/bug in the tune making poor decisions, or an issue with the system itself.

Coil/ignition issues are (usually) very obvious: either a constant misfire/dead cylinder, or a really bad miss (felt as "bucking") under loads.

Lifter issues at their terminal stages make a very gnarly TICK noise.

But a quick thing you can also check: Do you know whos been changing the oil? Not using 5w20 can also cause weird anomalies with MDS
 

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Discussion Starter · #10 ·
I'd have it flashed back to stock. Theres no guarantee any function would work they way its supposed to unless its stock. I'm almost positive this is either an error/bug in the tune making poor decisions, or an issue with the system itself.

Coil/ignition issues are (usually) very obvious: either a constant misfire/dead cylinder, or a really bad miss (felt as "bucking") under loads.

Lifter issues at their terminal stages make a very gnarly TICK noise.

But a quick thing you can also check: Do you know whos been changing the oil? Not using 5w20 can also cause weird anomalies with MDS
Thanks for that. I'll give it a shot. I imagine it'll have to be the dealer? Unfortunately, that will probably be immediately followed by me buying a new tuner, and getting a tune!

I've been doing the oil changes at 5000-6000 miles with synthetic 5w20
 

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Discussion Starter · #11 ·
I would give your tuner a call, this sounds like an MDS issue. Your tuner would be able to help you rule out if this is an issue with their programming or some kind of mechanical problem.

Were you around 2-3k RPMs when this happened? Sudden engagement of MDS at "high" rpms (the highest rpm stock programming will engage mds is 3k) will make a weird WAAAAAAAT sound, and is especially noticeable if you have aftermarket exhaust. With stock exhaust its like a deep dull jake-brakeish BUUUUR sound. I can PM you a video of the sound if you'd like - I can kinda force my truck to engage MDS at weird points.

That weird feeling that "something kicks in" would be the sudden torque spike when MDS disengages and reactivates the 4 disabled cylinders.
thanks, can I get the vid?
 
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