W156 Misfire
08-23-2019, 01:19 AM
#27
Junior Member
Thread Starter
See above on leak down.
Cam solenoids and cam adjustment gears were replaced when heads were done.
Cause or symptom the injector turns off at light load intermittnantly
Cam solenoids and cam adjustment gears were replaced when heads were done.
Cause or symptom the injector turns off at light load intermittnantly
08-30-2019, 07:12 AM
#29
I just changed all my plugs, and the injector and coil on cyl 7. Still misfires.
I did note that my exhaust cam positon values were fluctuating between -10 and +14 while cruising at that low rpm though
Both intakes were approx. +17 , and the other exhaust was about -6
I did note that my exhaust cam positon values were fluctuating between -10 and +14 while cruising at that low rpm though
Both intakes were approx. +17 , and the other exhaust was about -6
08-30-2019, 09:17 AM
#30
Junior Member
Thread Starter
How did you capture/measure that?
08-30-2019, 09:48 AM
#31
Live data on a scanner
I have a theory though. Disconnect the cam position sensor on Bank 2. Go for a drive. See if it still misfires without the cam adjuster running.
If its fine, then its either the cam adjuster or the cam position sensor
I have a theory though. Disconnect the cam position sensor on Bank 2. Go for a drive. See if it still misfires without the cam adjuster running.
If its fine, then its either the cam adjuster or the cam position sensor
Last edited by kkkk; 08-30-2019 at 09:51 AM.
09-07-2019, 02:39 AM
#34
no...the tune won't be specific to each bank. its pretty rare even with full standalones to allow for individual cylinder correction.
the M156 engine was CAD designed so I'd doubt the head flow characteristics to allow for a deviation of 11%. deviation is unavoidable with OEM built engines, but not of a spread of 11%. I'd look to maybe the possibility of air flow restriction of some sort? it wouldn't be a fuel flow issue as fueling will be based off metered air and oxygen sensor reading.
does your trims always have a 11% spread, or was it just this instance? my LTFT's with larger injectors and e85 tend to have a spread of about 3-7% at times, but never static.
anybody else here have any thoughts?
the M156 engine was CAD designed so I'd doubt the head flow characteristics to allow for a deviation of 11%. deviation is unavoidable with OEM built engines, but not of a spread of 11%. I'd look to maybe the possibility of air flow restriction of some sort? it wouldn't be a fuel flow issue as fueling will be based off metered air and oxygen sensor reading.
does your trims always have a 11% spread, or was it just this instance? my LTFT's with larger injectors and e85 tend to have a spread of about 3-7% at times, but never static.
anybody else here have any thoughts?
09-07-2019, 02:41 AM
#35
09-09-2019, 10:34 PM
#38
Im just going to replace my cam adjusters. Cant figure out whether its the intake or exhaust so Ill just do both I think.
It could be the solenoid I guess, and could just try switching those first .
It could be the solenoid I guess, and could just try switching those first .
09-11-2019, 07:42 PM
#42
MBWorld Fanatic!
09-11-2019, 07:55 PM
#43
MBWorld Fanatic!
Not sure why one of the 5 shops that took his car apart didnt notice the car sounding like rocks in the adjuster.
Feel bad as they took him to the cleaners changing everything but the one thing that is making noise.
Feel bad as they took him to the cleaners changing everything but the one thing that is making noise.
09-12-2019, 03:12 AM
#45
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'04 E55 (Gone but not forgotten), '13 C63 P31 (RIP), another '13 C63 PP
Do any of you guys have any weird sounding noises from the cam adjuster (intake)?
Im just wondering maybe someone skipped a step or something when putting the car back together after the headbolt install
https://www.youtube.com/watch?v=XhgVA6Ajm5w
Did your misfire come after the headbolt install dogtag?
What are your long term fuel trims like?
Im just wondering maybe someone skipped a step or something when putting the car back together after the headbolt install
https://www.youtube.com/watch?v=XhgVA6Ajm5w
Did your misfire come after the headbolt install dogtag?
What are your long term fuel trims like?
I hope you got that cleared up.
09-15-2019, 07:25 AM
#47
With the exhaust cam solenoid unplugged, the exhaust reads at -15.
I havnt looked to see what it reads with the intake cam solenoid unplugged, or if it defaults to a safe setting with the exhaust cam solenoid unpolugged.
I havnt looked to see what it reads with the intake cam solenoid unplugged, or if it defaults to a safe setting with the exhaust cam solenoid unpolugged.
02-19-2020, 11:44 PM
#49
Junior Member
Thread Starter
update: Pulled bank 2 apart. Changed camshaft adjusters, cleaned and flowed injectors, replaced all coils (again), found a nose seal on the cam that was in the wrong slot. Got that fixed, everything back together. And guess what.
With brand new cam solenoids plugged in, misfire on cylinder 7 still present.
Unplug exhaust cam solenoid. Misfire goes away entirely....at this point I'm completely at a loss.
With brand new cam solenoids plugged in, misfire on cylinder 7 still present.
Unplug exhaust cam solenoid. Misfire goes away entirely....at this point I'm completely at a loss.
