2014 Dodge Caravan Misfire P0305

hey everyone, new here - working through scannerdanners diagnostic book. dealing with a misfire that i cant figure out.... looking for some direction. thank you in advance!

2014 Dodge Grand Caravan 3.6L SXT

initial code was P0303, was due to burnt exhaust valve....replaced head. after repair still has misfire but now it has moved to P0305 which is the next cylinder over in the same bank/head. i dont know if maybe i got a bad head from the dealer or something is not in line on my side. i did a relative compression test that is attached and what sticks out to me is cylinder 5 will give 2 good rotations and then a bad 1, it keeps this pattern for as long as you crank. before doing this relative compression test i moved coils/plugs/injectors around with no change. also, passes leakdown test. cam lobs look fine, new rockers/lifters were installed with new head. what would you recommend i check next?

Put a pressure gauge in cylinder 5 and see what peak cranking pressure ,do a cylinder leak test , if you have a pressure transducer a running compression test may help with Tyler's overlay program (that he still hasn't shared with the rest of his best friends on here cough cough). you may find the problem with the leak down tester though seems like we went through this same problem on another 1 of these caravans on this site somewhere may try a quick search for it.

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Ben wrote: ...if you have a pressure transducer a running compression test may help with Tyler's overlay program (that he still hasn't shared with the rest of his best friends on here cough cough)...

:lol: You KNEW I'd read this thread! Truthfully, it's not because I don't want to share, just a big legal concern that I don't want to bring to SD.com or the forums.

You could also try a vacuum gauge on the manifold at idle. I'm sure you'll see some twitching of the needle, but I'd be interested to see if you get pressure pulses in the intake during the misfire. That'd suggest an intake valve that is sticking open. You could also put your hand over the throttle (with the throttle wide open) and see if you feel pressure pulses during cranking.

The same could be done at the tailpipe, but I'm not sure you'd feel it? Just because of the length of the exhaust.

Random thought, if it is regularly occurring every third stroke, you could rotate by hand the engine 3 times while doing a leak down on each peak. In theory one of the three should land on the "bad" stroke?

Tyler wrote:

Ben wrote: ...if you have a pressure transducer a running compression test may help with Tyler's overlay program (that he still hasn't shared with the rest of his best friends on here cough cough)...

:lol: You KNEW I'd read this thread! Truthfully, it's not because I don't want to share, just a big legal concern that I don't want to bring to SD.com or the forums.

.

Lol I'm under the impression is was either licensed as a freeware or shareware if you open the about tab it will say its licensing type and if it's either freeware or shareware you can legally share it as long as your not selling it.

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A secondary ignition wave form may reveal if there is any breathing or sealing within this cylinder. Get a parade wave pattern while cranking, at idle and snap throttle.
WOT while cranking will give you relative compression as well, as long as the engine does not start (it shouldn't at WOT in clear flood mode, otherwise disable the injectors).

Any update? I'd hate to see this conversation die.

Only thought I have to add is that it could be a collapsed lifter (or whatever you would call it on an overhead cam) and the "every 3rd" issue is oil pump / pressure related.