bentz69

16 CLS63S, 37k miles with the following mods for the past 20k miles. Eurocharged e50 tune with e45 in the tank, catless downpipes, blackboost intakes. Caught a flashing CEL during a wot run and went into limp mode. The car would not accelerate and pushing the gas peddle would induce slight shaking. Pulled over and scanned, #6 misfire. Cleared the code and went on my way. This same scenario happen only one other time at 18k miles in May 2022 with #6 and #8 misfire. Since then I haven't had an issue. I drive around 100 miles a day. Car still has the original spark plugs with oem gap.

When the first misfire happened I started data logging rail pressure and rpm to send eurocharged a log if a misfire happened again. I tried numerous wot runs over the course of a couple weeks and never had another misfire so I stopped logging. Eurocharged said oem plugs with oem gap were fine. Here we are 8 months later and the same thing happened again.

After I cleared the misfire I got back on the highway and the car felt fine but Im noticing a sporadic shaking at idle whether in park in drive. Feels like a random misfire. There is no steady CEL but when I scanned, the p300 random misfire is listed as pending. Now what scares me is the noise coming out of the driver side muffler only. It sounds like a tapping/stutter/knocking noise. Im not hearing any abnormal noise from the engine bay. Check the video.

PeterUbers

Ooph... sounds like piston slap or spun bearing

37k original coils and plugs and aggressive tune ... the latest misfire likely the other ones also were possibly bad plugs or coils and now this latest misfire caused some damage... I would expect to hear something in the engine bay if engine damage though however the m157 is a noisy engine even when normal

will wait for others to chime in

edit ** I actually hear the knock/slap in the engine bay if I listen carefully

bentz69

Plugs were on the to do list. Ive seen the recommendations of changing plugs every 10k miles but honestly, my driving style is literately grandma driving 95% of the time. Although I drive 100 miles a day, I could go 2 weeks without going wot. However, they were due for a change and I suppose Ill start there.

Ill give a better listen when I start the car again but the engine bay sounds the same to me like it always has. Those high pressure pumps are loud but I dont hear any ticking or slapping

PeterUbers

scope those cylinders while you're there and new coils too, also you're testing your e-fuel content?

bentz69

I have spools Bluetooth e85 unit. It works very well

jvakos

definitely want to get those OEM plugs changed if you're at 20k miles on them AND tuned.... most tuned guys are changing plugs every 5k to 10k miles and even changing coils in that interval. always start with plugs and coils with misfires on these M157 cars as the high boost from the tune can rapidly degrade the coils and accelerate the plug wear.

bentz69

After a short drive, the pending p300 misfire popped the CEL for a #6 misfire (same as the other day). Stopped by the dealer to pick up 1 oem plug and new boot (just in case it ripped) to start troubleshooting. OEM plug came out the box at .0024 so I left it alone. After removing the original plug it didnt visually appear to be in bad shape. The gap was .0026. No oil or fuel on the plug. New plug went in, original boot came off with ease and the car is good for now. No shaking at idle, no farting out of the exhaust, no cel. Drove for a while and shes running fine.

I did notice the upgraded boots now available, They have stronger plastic sleeve essentially covering the whole boot. Defintely more robust. In the meantime I ordered all new bosch plugs from amazon and Ill swap the rest when they come in.

wseikow

I have 2016 E63. I had misfire. brought to dealer . Says cylinder 5. They did some test etc. Gave me the car back to drive and see if it occurs again . Drove it 10 minutes and happened again.
Brought it back to dealer. They opened a trouble ticket or something with AMG techs offsite.
Waiting to hear back.
Find it strange that with codes etc they can;t pin point something.

Thanks for any insight. I am not knowledgeable about these things... I just drive cars.

Thx

bentz69

Well it seems when it comes to misfires there's 3 things to check and usually in this order from what Ive read. Spark plug, coil pack, injector. A misfire code on the #5 cylinder obviously points to a specific cylinder and these items should be changed first. If you have a warranty then let the dealer figure it out. If not, a second opinion from a non-dealer mechanic that specializes in MB would be wise

wseikow

@bentz69
Thx bentz69
This morning the dealer messaged me and told me they Recreated the misfire.
They say they will replace all spark plugs , 1 ignition coil and 3 injectors.

For you experts, does this compute? Should I give them additional feedback or anything?
Many thanks.

PeterUbers

sounds like they are on it, you should be good with this exception:
- I would ask if you can pay to replace all coils not just the one

jvakos

ask them to share the pressure/test data on all your injectors as I'd be curious to see what the 3 bad ones were showing and how the other 5 compare as maybe they replace other injectors that were on the lower end of the performance range. those are expensive so if they're replacing under warranty then for sure ask.