2015 Chrysler 200 3.6 liter misfiring on cylinders 2 and 4 after left bank exhaust camshaft and rocker replacement
We have a 2015 Chrysler 200 S with a 3.6 liter that came in with a ticking noise. Our technician determined that it was coming from the front valve cover. After removing the valve cover it was found that a couple roller rockers were worn and had worn the camshaft. Our technician replaced all the roller rockers, tappets and the left bank exhaust camshaft. After re assembly the car was started and had misfires on cylinders 2 and 4. After tear down again, absolutely nothing was found to be incorrect. Our technician also swapped cylinders 2 and 4 coils and plugs to a couple cylinders on the rear bank while the intake manifold was off, just to rule those out as a possible cause. After re assembly, the misfires were still on the same cylinders. After attempting further diagnosis, the misfire monitor will now not run and displays “Global Disable”. The technician attempted a cam/crank relearn but to no avail, the misfires are still present. The technician has performed repairs on 3.6 liter pentastar engines before but has never experienced this particular problem before. Any help with this situation would be greatly appreciated!
Hello, Nathan. I'm not going to be of much help, but FWIW, I had a 2014 Chrysler van display “Global Disable” on the misfire monitor. No P0300 codes, no misfire counts, nothing on Mode 6 except “Global Disable.” We finally pulled the intake to find a single spark-perforated coil boot that would misfire only at full operating temperature. This was weird because the engine would begin misfiring…
Once you clear the codes it has to pass the monitors before you get the misfire detection back. Don't clear the codes on a Dodge until it is fixed or you loose the misfire detection
Correct. Most chryslers will also disable misfire detection at low fuel levels (evidently they dont want codes set on cars under warranty due to the operator running it out of fuel)
Thanks for the info, Scott. I don't recall the system having any codes, which is why I had to pull the intake to physically inspect the coils, boots, and spark plugs. In this case, I performed the acceleration/deceleration routine and added gas to make sure the misfire monitors would run, but with no result. In general, I don't clear codes until the job is done, so I have no idea why it wasn't…
The owner, who happens to be a good neighbor, originally asked me if I could come to his place to “listen” to his engine. I explained that listening to engines went out circa 1958 and that there was a lot more to a diagnosis than he could imagine. So he gave me full authorization to do what was needed to fix the vehicle. My biggest mystery is why I couldn't get the misfire monitors to run. Never…
Disable the fuel system, put a pressure transducer in the intake to compare each cylinder's intake stroke vacuum pulls and another transducer in the tailpipe, to compare each cylinder's exhaust pressure pulses, then crank the engine to see if there are any valve train issues. This capture is from a 2016 Caravan 3.6 with misfire codes. The red channel is a pressure transducer in the…
How is the resistance on 2 and 4 injectors compared to non misfiring cyl
This capture was taken during a 1500 rpm brake torque. The red channel shows the spark plug spark voltage rising because there is no fuel in the cylinder. The blue channel shows the good spark plug spark time.
If these misfires were not there before, I have would suspect the cam timing got off a bit? Or the magnetic wheels on one of the cams has an issue?
cam/crank relearn in the scan tool is a carry over from the days of ole. Even though it is still shown in the scan tool it is none functional. Only way to get it off global disable for that engine is to drive it and perform 4 or 5 long decel's from 4000 rpms down to 1800. It is best to put the transmission in manual shift mode or in low 2 to accomplish this as gear changes cancel the learn…
"Only way to get it off global disable for that engine is to drive it and perform 4 or 5 long decel's from 4000 rpms down to 1800." Yikes! They certainly didn't want any normal driving to accomplish it, did they? Awesome tip Chuck!
We have a lot of wide-open asphalt roads with little traffic. I tried this procedure 3-4 times, no result. Of course, I'm either going uphill or downhill, which might make a difference :0)
Possible valve seating issue now that the valvetrain is restored to normal. Not sure how you would check it as it's under the intake manifold.
While I'd think this unlikely, a leak down test would answer the question.
I for one, do not know how you would have valve problems when there were not any before. I feel it is still most likely a mistake in the assembly which occurred despite you saying it was apart again to check. I do not know if the cams could ever be mixed up between intake and exhaust? You did not say if there are any noises now? Could any of the cam followers (rollers) be out of position at…
I have experienced this on a few . The global disable reasons are visible with witech but unsure of other scan tools . Fuel level should be above ¼ but most likely it’s from So much movement in crank sensor signal from misfires . I usually see this when there is a ignition misfire . —. Perform battery disconnect and touch terminals together for a few minutes . — Try a Pcm reset if you have…
I know you mention your technician has performed repairs with 3.6L engine, is it possible something magnetic was close to the tone ring. Did he wipe the metal filings off the tone wheels? Magnetic parts tray set on the valve cover?
Check compression these engines have valve seat issues with left bank. Also in most cases of rocker failure on these engines is caused by low oil pressure due to bleed off at the head. Just under camshafts are 2 bolts that are parallel with cam.one under each camshaft. These being loose is the actual cause of the rockers failing. Every one iv done have been loose. Also camshaft can…
Thank you everyone for your input! We are just now getting back to work on this vehicle (you know how it is trying to schedule work) and my technician has done a compression check and cylinder leak down on the left head. Cylinders 2 and 4 (the ones that are misfiring) have extremely low compression (<14 PSI) and cylinder 6 has a normal 180 PSI. What I find odd though is both those cylinders…
Hello, Nathan. In your case, the two offending cylinders passing a leak-down test indicates that the valves and piston rings are sealing the cylinder. So I'm speculating that the intake valves simply aren't opening. So faulty lash adjusters could be the cause. We have a lot of junk parts on the market and car owners looking for the lowest price often get these types of unpleasant…
Can you easily crank/and or briefly start the engine over with the cam cover off while watching the valvetrain? the engine was running on all 6 when it came in now after changing parts you have 2 cylinders down leakdown passed so it is unlikely that other parts were damaged if problem isn't visible with cover off then my next step would be in cylinder pressure transducer testing its…
Actually, the leak-down didn't pass. Because he did a static leak down which is only half of the test. You can't just crank the piston to top dead center, pump it up and call it good. You have to advance the crankshaft forward and back to see at what point the valves start to open.
Nathan, I think Gary has a great thought but I am not sure you don't get enough intake opening with a collapsed lifter as how on earth would the engine ever start easily when it has new lifters? I will go in the same direction but different. How about there are some rags in the intake ports that did not get taken out before reassembly of the plenum?
This capture is from a GM 5.3. The yellow channel is the relative compression starter amperage. The green channel is a pressure transducer in a cylinder and the cranking cylinder compression measures 16psi. The intake valve is not opening.
Ok everyone, we found the problem! Once again, thank you all for your help! To start, we were wrong on the cylinder leak down, we were using a faulty tester. After performing the test with another technicians leak down tool, we found the leak down to be close to 100%. With this, we decided to tear the timing cover and left cylinder head down to simply ensure it was not an issue we caused. After…
That is what I was suspecting,that is the most irritating thing to try to explain to a customer. A repair that causes another problem to surface is very frustrating. Glad you found the problem
Hello, Nathan. I've learned to quote engine repairs at the extreme end. As others have said, these engines tend to drop valve seats. Fewer shops are getting into internal engine repairs due to the high risk and liability. Unless it's a fairly new vehicle, Our local dealership quotes a new engine on anything that requires removing the heads or oil pan. Can't say as I blame them…
Nathan, court battles are usually pretty destructive to everyone involved. The waste of time alone will cost you more than you think. Maybe you should consider trying to come up with a solution to avoid court? We never know just how a judge may see things and once they are involved, you may not like the outcome. It is unfortunately highly coincidental for the valve seats to drop just as you put…
Yes David, I am trying my best to lower the temperature. I am currently trying to come to an agreement with the customer so all this can be avoided.
I agree with David. If the case goes to small claims court, you'll probably lose because judges don't understand technical issues very well. The only thing that counts is expert testimony and that can get expensive. If it were me, I'd sell him a new head at cost and reassemble the engine for the original quoted price. If he won't accept that, I would do whatever it takes to get the vehicle back…
Nathan- I have replaced about 92 left pentastar cylinder heads , 43 cars with rocker arms and maybe 2 2014 and up left heads for valve seat uneven sealing like you said . This is in no way the techs failure . Dealers tend to set aside 100 k for these freak failures . My advice is to set aside a percentage in a savings account as crap happens funds . Then I would tell customer it’s on you but…