S500 Occasional misfiring of cylinder 3
Thread Starter
Newbie
Joined: Jan 2016
Posts: 2
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2004 /W220 S-320 CDI
S500 Occasional misfiring of cylinder 3
Hi everybody,
I have very annoying error, which I would like to share with, and I hope some of you have met something like this before.
I have a 2008 W221 S500 vehicle (motor code: M273 5.5L). In the beginning of the day, I start the car, and everything is perfect, the roaring sound is nice, and the 8 cylinder evenly work. When I stop it and restart it after ca. 20 minutes, the idling is uneven, and the engine is also weaker. The engine check lamp is first blinking/flashing and then lights continuously. If I stop the engine and restart it after ca. 2-3 hours everything is perfectly fine again, and the engine check lamp is not on. This error never occurs while driving, only if I stop the engine and restart within short time, but not always. There are days when no error occurs at all. Sometimes, it occurs when it idles too much (ca. 10-15 minutes)
The diagnostic tool says that the cylinder 3 misfires. For test, first, I swapped the transformer of cylinder 3 and 2, then the spark plugs, then the injectors, but in every case, the diagnostic tool says the problem is with cylinder 3.
I don’t have any more idea about the problem and I just hope that some of you had this problem and have some solution for this. I hope you have some idea.
Thank you,
Arpad
I have very annoying error, which I would like to share with, and I hope some of you have met something like this before.
I have a 2008 W221 S500 vehicle (motor code: M273 5.5L). In the beginning of the day, I start the car, and everything is perfect, the roaring sound is nice, and the 8 cylinder evenly work. When I stop it and restart it after ca. 20 minutes, the idling is uneven, and the engine is also weaker. The engine check lamp is first blinking/flashing and then lights continuously. If I stop the engine and restart it after ca. 2-3 hours everything is perfectly fine again, and the engine check lamp is not on. This error never occurs while driving, only if I stop the engine and restart within short time, but not always. There are days when no error occurs at all. Sometimes, it occurs when it idles too much (ca. 10-15 minutes)
The diagnostic tool says that the cylinder 3 misfires. For test, first, I swapped the transformer of cylinder 3 and 2, then the spark plugs, then the injectors, but in every case, the diagnostic tool says the problem is with cylinder 3.
I don’t have any more idea about the problem and I just hope that some of you had this problem and have some solution for this. I hope you have some idea.
Thank you,
Arpad
Super Member
Joined: Dec 2018
Posts: 857
Likes: 501
From: Washington, DC
2007 S600, 2007 Chrysler 300 SRT8, 2000 C5 Corvette, 2017 Mustang GT, 2023 300C, and a 2019 Lincoln
It should have moved cylinders when you moved the coil. If it doesn't, that seems to indicate a problem in the original cylinder. I might do a bore scope check on that cylinder for problems in that bore or on that piston top. It could also be the fuel injector in that cylinder. I would bet it is the fuel injector.
MBWorld Fanatic!
Joined: Aug 2014
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S500
CRANK POSITION SENSOR - (AKA CPS) - these fail all day long - meets a lot of the points you make = correct tools 20 mins and $50 and needs doing every 50k miles
sensor cold and it behaves - In the beginning of the day, I start the car, and everything is perfect
sensor hot and failing (perfect description of the faults) - When I stop it and restart it after ca. 20 minutes, the idling is uneven, and the engine is also weaker. The engine check lamp is first blinking/flashing and then lights continuously
sensor cold again - after ca. 2-3 hours everything is perfectly fine again, and the engine check lamp is not on.
BUT you should see this error display in diagnostics
as for the 8 individual coil packs - these fail at a rate that makes the CPS look like it has a 20 year warranty
swap the number 3 coil pack to any other location and see if the fault moves....
sensor cold and it behaves - In the beginning of the day, I start the car, and everything is perfect
sensor hot and failing (perfect description of the faults) - When I stop it and restart it after ca. 20 minutes, the idling is uneven, and the engine is also weaker. The engine check lamp is first blinking/flashing and then lights continuously
sensor cold again - after ca. 2-3 hours everything is perfectly fine again, and the engine check lamp is not on.
BUT you should see this error display in diagnostics
as for the 8 individual coil packs - these fail at a rate that makes the CPS look like it has a 20 year warranty
swap the number 3 coil pack to any other location and see if the fault moves....
Super Member
Joined: Dec 2018
Posts: 857
Likes: 501
From: Washington, DC
2007 S600, 2007 Chrysler 300 SRT8, 2000 C5 Corvette, 2017 Mustang GT, 2023 300C, and a 2019 Lincoln
Can I change my diagnosis? Before you go internal to that cylinder, try BOTUS' suggestion. I think once again, BOTUS is right. Crankshaft position sensor could well be the problem. It is also pretty cheap so if it is old, start there. Then let us know. Sorry if I started you off on a wild goose chase on that fuel injector.
Thread Starter
Newbie
Joined: Jan 2016
Posts: 2
Likes: 0
2004 /W220 S-320 CDI
Thanks for the quick suggestion.
I did changed the coil pack 3 to another location, but the fault did not move.
Can a faulty CPS cause a problem for only one cylinder and always for the same one?
I did changed the coil pack 3 to another location, but the fault did not move.
Can a faulty CPS cause a problem for only one cylinder and always for the same one?
Super Member
Joined: Dec 2018
Posts: 857
Likes: 501
From: Washington, DC
2007 S600, 2007 Chrysler 300 SRT8, 2000 C5 Corvette, 2017 Mustang GT, 2023 300C, and a 2019 Lincoln
Maybe only one cylinder currently. Typically, the symptoms of a CPS problem show up on fueling the car. You drive in with no miss and no issues just to get gas. The car is warmed up and while you are filling the tank, that CPS heats up; and after you close the fuel door, the car will crank but no start. Wait until that CPS cools down, and she will fire right up. Eventually, the CPS will fail enough to refuse to start. I bet yours is sending you a love note.
Keep us posted.
Keep us posted.
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MBWorld Fanatic!
Joined: Aug 2014
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S500
have had a few where it seems to be number 3 all the time - more recent posts have pushed the thinking towards a failed ECU due to ingesting gunk from leaking cam sensor magnets... by an odd quirk of fate (deliberate design) oil wicks down the wiring loom from the cy head cam sensor magnets and in to the ECU (over time - sometimes many years. Oil on its own should NOT destroy electrics but dirty gunk with combustion acids and moisture might !
you wouldn't be the first - if this seems to be the case your warranty and dealership stitched you up - they all leaked (and still do a bit) and the looms were meant to be retrofitted with a gunk stopper - you need new cam sensors - new wiring looms (or the residual oil will take out the new ECU) and likely a new ECU - note aftermarket bosch ECUs are 1/3 the price for the same thing - but will need a genius to get a map and the immobiliser info in there... MAY be a chip tune lot ?
you wouldn't be the first - if this seems to be the case your warranty and dealership stitched you up - they all leaked (and still do a bit) and the looms were meant to be retrofitted with a gunk stopper - you need new cam sensors - new wiring looms (or the residual oil will take out the new ECU) and likely a new ECU - note aftermarket bosch ECUs are 1/3 the price for the same thing - but will need a genius to get a map and the immobiliser info in there... MAY be a chip tune lot ?
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Joined: Aug 2014
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S500
diagnostics are the same on any reasonable kit these days - its the nursemaid hand holding and then higher level play time - like flashing and coding where dealer kit can be essential
when the car is properly muddled with a dead or part dying component all the diagnostic info goes to **** - and that where life lets u down - if it can't remember whats wrong or is so muddled / or dead that it doesn't communicate correctly, the car will tell you nothing or worse start to invent lies that lead you off in the wrong direction
if the fault isn't saying CPS, nor moving cyls it should never have been the CPS (but if old or orig sensor do it anyway as will just let you down next week) and its not the coil pack at fault - it could be wiring to that cyl - BUT and I believe we see it on the V12 too - when all else fails just say its number 3 - and it tells dealers who get support from the factory that's a default to say its muddled so try this.... I think the "this" is sadly the post above !!!!
http://mbworld.org/forums/attachment...2_modified.jpg
https://forums.mercedesclub.org.uk/index.php?attachments/0813e9dc-a5ae-4b3b-8ed5-ef2f80bd5af3-jpeg.73371/
.
when the car is properly muddled with a dead or part dying component all the diagnostic info goes to **** - and that where life lets u down - if it can't remember whats wrong or is so muddled / or dead that it doesn't communicate correctly, the car will tell you nothing or worse start to invent lies that lead you off in the wrong direction
if the fault isn't saying CPS, nor moving cyls it should never have been the CPS (but if old or orig sensor do it anyway as will just let you down next week) and its not the coil pack at fault - it could be wiring to that cyl - BUT and I believe we see it on the V12 too - when all else fails just say its number 3 - and it tells dealers who get support from the factory that's a default to say its muddled so try this.... I think the "this" is sadly the post above !!!!
http://mbworld.org/forums/attachment...2_modified.jpg
https://forums.mercedesclub.org.uk/index.php?attachments/0813e9dc-a5ae-4b3b-8ed5-ef2f80bd5af3-jpeg.73371/
.
Last edited by BOTUS; Jun 12, 2023 at 04:01 AM.
MBWorld Fanatic!
Joined: Aug 2014
Posts: 5,319
Likes: 1,675
S500
dam parts drawing say I'm right
Merc
070 POSITION SENSOR
CRANKSHAFT POSITION SENDER UNIT
https://nemigaparts.com/cat_spares/e...asis=22107163W
Ford
Sensor - Crankshaft Position - Cps
https://ford.7zap.com/en/car/43/1.19...6/15482/67396/
but I do see the halfwits at BM confused themselves
the "crank sensor" is NOT to tell you there is one there - its to tell you the position its in - morons
.
Merc
070 POSITION SENSOR
CRANKSHAFT POSITION SENDER UNIT
https://nemigaparts.com/cat_spares/e...asis=22107163W
Ford
Sensor - Crankshaft Position - Cps
https://ford.7zap.com/en/car/43/1.19...6/15482/67396/
but I do see the halfwits at BM confused themselves
the "crank sensor" is NOT to tell you there is one there - its to tell you the position its in - morons
.
Last edited by BOTUS; Jun 14, 2023 at 07:09 AM.
