2009 Hemi Misfire at Idle

[AlexT]

Hello, I've got a 2009 5.7L with 173k miles on that has been having issues with a shaky idle and occasionally a P0306 code that I've been chasing for a while and am not sure where to go next.

Symptoms: Misfire at idle that goes away under load or above ~1k RPM, it is definitely a lot worse on a cold start and seems to improve once it warms up but never completely goes away. I can still rev out the engine smoothly and haven't noticed any decrease in MPGs. I've found if I let it idle too long, it will throw up the P0306(cyl 6 misfire) code but it doesn't count any misfires at cruising rpms. Occasionally it will misfire as I slow down for a turn. It has never stalled on me. I can also hear an intermittent ticking coming from the passenger side, I think it has been there a while but I always assumed it was an exhaust leak tick because I have a few broken exhaust manifold bolts on the pass side. Now I'm not so sure.. In the video you can clearly hear the intermittent ticking at about the 14s mark. Usually its more apparent when the engine is cold started and gets a little better once warm.

https://youtu.be/Yroy4vEEyvA
Diagnosis attempts: I started by checking out the spark plugs (looked good, only 25k miles on them) and coils, and also swapped them between cylinders but the misfire did not follow. I replaced the injector on that cylinder with a new mopar one and saw no change. I thought maybe it was a vacuum leak so I replaced the intake manifold gaskets, cleaned up the intake/TB, and still saw no change. I checked compression between cylinder 6 and 4 and they were similar and seemed to be in a good range. I changed the oil with penzoil platinum 5w20 since it was due already and it may have helped some but it is still present. I took an oil sample and sent it off for testing in the process but it will be a few weeks before I get the results. Lastly, I popped off the passenger valve cover to check for the dreaded lifter/cam failure issue I've been reading a lot about and it was inconclusive, at least to my eye. My neighbor is a mechanic and I had him come over and take a look with the valve cover off, he checked tension on the rocker arms/springs and watched it turn over and didn't notice anything abnormal either. Here's the video I took:

So that's where I'm at and I'm kind of lost as to where to look next. It drives around just fine but misses at idle. Has anyone dealt with this before or have any ideas of what to check next? At this point I'm thinking it could be a sensor or something PCM related? Part of me thinks it could be a lifter, but I'm not sure why it would miss at idle and not at high RPM. Any help is appreciated, thanks.

 

[Burla]

Hemi plus misfire with hemi tick= new cam lob and lifters. Sounds like you have some mechanical ability, read this thread. That fact a new oil change helped a bit kinda tells the story, it is lifters. Might want to read the threads on my sig, maybe help you with new cam when you replace it. Smart move swapping coils, bad news misfire did not move. Writing on the wall, sorry man. Not that I recommend this, but only hope an oil will make it last a little longer, go thick. Missing at idle is what to expect, the lifter is dry and has no fluid friction roller versus cam lob, the lob is worn to the nub, lifter will not lift correctly. It's a matter of time before it is missing all the time.

If you want to absolutely verify all it can be, check valves, but this is a known issue and most of the time it is cam lob.

I hope you stick around and learn and report how everything worked for you, and especially how that uoa turns up. We have a blackstone thread, whatever lab you used I hope you post the results, thanks Burla.

sorry for the troubles

 

[Tim Garceau]

Your symptoms and troubleshooting do point to a seized roller from the history of this engine. However, number 6 appears to have decent rocker travel so it may be in the early stages if you have not driven too many miles with it especially if it only flares up during cold start and lower oil pressure(hot idle). Might have to get out the feeler gauges to have a more accurate comparison between 6 intake/exhaust and another hole.

Did you cut open the oil filter and inspect the media? Good call on the analysis as your wear metals should be well above average if that is the culprit.

Keep us informed. If you were to crack the heads off now this may tell us if a needle bearing failed or due to excessive mileage, they just wore down where they had so much clearance the roller is rocking and audible. Normally users put more miles on and by that time the similar hardness between the roller/cam start compounding the decrease in valve travel.

 

[AlexT]

Part of me knew in the back of my mind that this was probably the issue, I was just hoping that maybe there was something I wasn’t thinking of that could’ve caused these symptoms. I do have some mechanical ability but mostly suspension, brakes, and maintenance. I’ve never had the heads off of engine or swapped out camshafts. After reading through that very helpful thread and watching many YouTube videos I think it’s something I’m capable of but does seem like a tedious process. Thankfully I’ve got a workshop in the back and a weekend car I can drive in the meantime if I do decide to take some time and do it myself. Any idea on time commitment this would take or approximate labor cost to have a shop swap the lifters and camshaft? Also do people usually replace valve seats while the heads are off? I know that was a failure point pre ‘09 but not sure if it was still something to look out for.

How quickly do things go down from here? Is there risk to anything else if I drive it a bit further? I’ve got a 2k mile road trip coming up in a month that I should probably make alternate arrangements for or try and get it fixed before then..

I guess I could use this as an opportunity to do a performance cam but this was supposed to be my quiet comfortable daily driver/tow vehicle compared to my Mustang GT track car haha.

thanks for you alls help, as you can tell from the video this is actually on a Grand Cherokee but they didn’t have a whole lot of insight on those forums. It looks like y’all have a pretty good knowledge base over here and I appreciate that. I’ll definitely keep y’all updated because there nothing worse than a thread with no resolution.

 

[Burla]

Depending on your locale the wide range on average cams is wide, 1800 to 3800 seams to be the range, at dealer it seams to be 3800 to 7500, but it has even been higher. Occasionally the many subsidizes the job, and people pay as little as 1800 even out of warranty, this is rare but it has happened. I think most people replace lifters and cam, as that is what the actual issue is, but who knows about valves, maybe it is a good idea while everything is open.

I've taken my bumper off, that can be a job, a couple bolts in fender jammed me up, maybe those arent on your vehicle. I think pro's can do the cam lifters in 4-8 hours, especially if the bumper is off. I think most will be 8 for sure, even if they do it in less time, one of those things. An amateur job, shot in the dark - 7 days of tooling, maybe get a friend who had a muscle car before. Pay attention to the push rod install, that is the number one thing jamming up these cam swaps, even pros have gotten this wrong. Really re-read that thread. Let us know what you will do, gl Burla.

 

[Burla]

I’ll definitely keep y’all updated because there nothing worse than a thread with no resolution.

Thanks for this bro. Ask for the Cam, take a picture of the wiped lob, we are sadistic that way.

 

[AlexT]

A bit of an update: I took it to a mechanic for further diagnosis and they found compression on that cylinder was a little low, they said 70-80 vs 100-105 for others. I had them take the valve cover off and investigate further and they determine that the exhaust valve on that cylinder wasn’t closing completely. They said they needed to remove the head to investigate further but seemed to think it was a sticking valve lifter that wasn’t allowing the valve to close all the way. I had them stop at that point, they quoted me worst case scenario of replacing all lifters and the cam and said it didn’t make sense to continue digging unless I was willing to go all the way.

It’s not quite the diagnosis I expected, they were sure it was an issue with the valve not closing 100% vs the common hemi lifter failure where the valve doesn’t open. They didn’t seem to think it was a bad valve spring but didn’t rule it out either.

if it truly is an issue of the valve lifter sticking intermittently, my neighbor suggested doing an oil treatment like marvel oil and then changing the oil with something like redline. Changing the oil did seem to help some so it seems this could help some more?

At this point I think I will try the oil treatment next, and if that doesn’t work I’ll probably remove the head myself and get a clear picture of what’s going on. I’m really hoping it is just the lifters on that side that would need replacement and not the camshaft as well. I should get my uoa back in the next week or two and that should give me a good idea if the camshaft is wearing.

 

[ChevySlayer69]

Pulling the head shouldn't be that bad. If you're lucky the failing lifter might not have chewed the cam yet. Or you could just trade it in...

 

[AlexT]

I got the blackstone analysis back today and the results look to be promising. Would this give the impression that my camshaft is probably fine? I may be comfortable replacing the lifters myself, I was just really dreaded the idea of having to do the cam as well.

 

[Burla]

Maybe, just have a back up plan. I can't imagine if the lob is wiped and you put lifters that any damage will occur to new lifters. The wear numbers aren't cut and dry, with 170+k miles and a short interval, those numbers aren't insignificant. It is very possible that the lob wore out over time as opposed to just the last oil interval. Hard to say how or why with that many miles without a longer report. But yeah it looks good for a hemi. I would like to be more positive, but quite often your symptoms = cam lob nubbed out.

 

[burner71]

Check your valve spring, could possibly just need a new spring.

 

[Black-Ram15]

I got the exact same symptoms on mine. I have almost replaced every single sensor but nothing gas changed. It started with a minor tick about 2 months ago. I was running pup oil and immediately did an oil change using redline 5w-30. The tick went away almost immediately but stared to have the exact symptoms AlexT has.

I have already bought an aftermarket cam and hellacat lifters back when it started the tick.

The wife is going to love this one.....hehe

 

[AlexT]

Despite me trying to rationalize it being anything but a failed lifter, I started tearing it down last week and discovered a failed exhaust lifter for cylinder 6. I decided to order a complete MDS delete kit with camshaft and the upgraded hellcat lifters in the hopes I never have to deal with this again. Spent most of the day working on it and was able to get the camshaft swapped out, timing set, and timing cover back on with the help of my neighbor. I sent the heads off to the machine shop to get surfaced and pressure tested so those won't be going back on until next weekend. Nothing has been overly difficult thus far, but there are just so many steps I hope I don't forget something as it goes back together.





View attachment 223594

 

[Burla]

Despite me trying to rationalize it being anything but a failed lifter, I started tearing it down last week and discovered a failed exhaust lifter for cylinder 6. I decided to order a complete MDS delete kit with camshaft and the upgraded hellcat lifters in the hopes I never have to deal with this again. Spent most of the day working on it and was able to get the camshaft swapped out, timing set, and timing cover back on with the help of my neighbor. I sent the heads off to the machine shop to get surfaced and pressure tested so those won't be going back on until next weekend. Nothing has been overly difficult thus far, but there are just so many steps I hope I don't forget something as it goes back together.

View attachment 223593

View attachment 223592

View attachment 223594

You are a man of your word, good man there. Thanks for updating us, and again sorry for the troubles. I'd just ask you to look at the hemi tick lubrication threads. You are doing upgrades that is nice, but also develop a strategy that will help those lifters slide and not create back pressure on the lobs.

 

[Tim Garceau]

Was that roller assembly rough in rotation or did the lifter spin in the cradle? At least from the photo it appears to still have function since the roller doesn’t have a flat spot.

Appreciate the follow up, give your filter a pat on the back keeping the oil from extreme contamination. You’d expect to see increased iron levels.

 

[AlexT]

You are a man of your word, good man there. Thanks for updating us, and again sorry for the troubles. I'd just ask you to look at the hemi tick lubrication threads. You are doing upgrades that is nice, but also develop a strategy that will help those lifters slide and not create back pressure on the lobs.

It's always so frustrating when you have symptoms that nobody else seems to have had, I had to update it for the next person that gets to go through this. I read through the oil thread and it seems the consensus is the redline 5W30 which I do intend to switch to after I do a 1k mile break in oil change. I'm not sure what else you are referring to when it comes to 'not creating back pressure on the lobs' ?

Was that roller assembly rough in rotation or did the lifter spin in the cradle? At least from the photo it appears to still have function since the roller doesn’t have a flat spot.

Appreciate the follow up, give your filter a pat on the back keeping the oil from extreme contamination. You’d expect to see increased iron levels.

Probably about 1/2 of the needle bearings were missing so it would still spin but was very rough. I think I likely caught it a little earlier than most people. Every other lifter/camshaft lobe looked pristine after 173k miles, I'm not sure why this one decided to give up the ghost other than just bad luck. I'm not totally sure when I started hearing a tick, I had some broken exhaust bolts too so I assumed that's what it was for the longest time.

 

[Burla]

In hemi tick, when the lob hits the lifters, the lifters aren't sliding though the cavity smoothly, thus the force trying to push them is the force that is receiving the pressure, IE the cam lob. If the lifters are lifting properly, the cam doesn't wear out. Uncle Tony's lifters showed a bad case of exactly this, with wear on the side of the lifters. The metal assay shows that on worn cam lobs, the metal was in fine condition. It would not matter the metal make up of the lob, if there is resistance in the lifter cavity from perpendicular force, that isn't going to stop a cam lob spinning with 390hp behind it, it simply will absolutely force that lifter through the cavity regardless, thus we get tick and heavy wear.

Part of the reason why redline works is it makes those perpendicular forces smooth, that is the science of those additives. Once those perpendicular forces are smooth, the truck simply doesn't tick, the force creating the issue is solved, gone, **** like a fart in the wind. Read those lubrication threads, see the assay, the engineers words on oil formulas, uncle tony's proof even though he got some things wrong, the fact we killed hemi tick if you give it half a chance, the entire thing has came together. It may not be 100%, but it surely was a yeoman's effort here at ram forum to put all of this together and find something that actually has been killing these ticks, instead of doing nothing or begging fca the feckless manu to do something.

 

[Burla]

Probably about 1/2 of the needle bearings were missing so it would still spin but was very rough. I think I likely caught it a little earlier than most people. Every other lifter/camshaft lobe looked pristine after 173k miles, I'm not sure why this one decided to give up the ghost other than just bad luck. I'm not totally sure when I started hearing a tick, I had some broken exhaust bolts too so I assumed that's what it was for the longest time.

Can you expand on that, the needle bearings were missing when the engine was operating? The lob that was wiped lifter still had in tact roller/bearing?

 

[AlexT]

After closer inspection I noticed that the pin that the roller spins on had shifted to one side and actually made it difficult to pull the lifter out of the bore. I had to use a pair of channel locks and slowly wiggle it out of its bore. I slid another lifter into the bore afterwards and it slid smoothly so there wasn't any damage to the block. You can see in the picture above that the pin shifted slightly towards the bottom of the pic. I'm wondering if possibly that happened first and caused increased pressure on the cam lobe and led to the needle bearings starting to disintegrate. When I tore it down the roller would still spin but it had maybe 1/8" of play and was definitely missing some of the needle bearings.

 

[AlexT]

After a full weekend in the workshop putting the Jeep back together I was finally able to start it up Sunday night. It ran a little rough and smokey at first, and threw a CEL but it eventually smoothed out as all the crud and oil that had gotten in during assembly had burned off. It also looked like I was sending smoke signals under the hood due to all of the oil and lubricant that had gotten all over the exhaust . Eventually that all cleared up as well and I took it on its first test drive successfully. I cleared the CEL and have since driven about 300 miles with no issues! I went ahead and did an oil change after 100 miles just to flush out anything that may have gotten in there during assembly. After not having driven it in almost a month and half I'm so excited to have my Jeep back running again just in time for a Texas winter!! Special thanks to my neighbor and my dad for loaning their time and tools on a few occasions.

For anyone considering doing this fix themselves know that there isn't any one thing that is super difficult, there are just a ton of steps to follow and a few critical things that must be torqued correctly. It took me probably 30 hours of work over 3 weeks to tear it down, replace the camshaft, and rebuild it. Knowing what I know now and assuming I don't have to wait on parts, I could probably do it in a 3 day weekend. With the labor required and the parts cost markup I estimate I saved probably $2500-3k vs the quotes I had gotten from 2 different mechanics. I feel pretty satisfied that I was able to do it myself but this project dominated my freetime and stressed me out for a good 3 weeks so I totally understand why most people would just spend the money to not have to deal with it.

The Jeep is at 173k miles now and with the refreshed engine the goal is to go at least another 50-75k before I look into replacing!