Help - Missfire C300 3.0L 272
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Joined: Jan 2022
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2009 Mercedes C300 4Matic sport, 2008 Chevrolet Suburban, 2002 Corvette Z06, 2002 Workhorse Monaco
Help - Missfire C300 3.0L 272
I need some help with a misfire on my C300.
History: I was on my way home from work and got off the freeway. came to a stop and the MIL light came on and the engine felt like it was misfiring.
Checked the codes and had the following: 0600, 0601, 0605, 0606 or P300, P0301, P0305, P0306
This is what I have done so far.
1. Checked fuel pressure - good
2. Checked cylinder compression - 150 +/- 5
3. Checked the MAF sensor - good
Proceeded with the following:
1. Changed the spark plugs
2. Changed the coils
3. Changed all the injectors
4. Changed all of the cam sensors
5. Changed the Crankcase sensor
I still have the same issue. any help would be appreciated.
History: I was on my way home from work and got off the freeway. came to a stop and the MIL light came on and the engine felt like it was misfiring.
Checked the codes and had the following: 0600, 0601, 0605, 0606 or P300, P0301, P0305, P0306
This is what I have done so far.
1. Checked fuel pressure - good
2. Checked cylinder compression - 150 +/- 5
3. Checked the MAF sensor - good
Proceeded with the following:
1. Changed the spark plugs
2. Changed the coils
3. Changed all the injectors
4. Changed all of the cam sensors
5. Changed the Crankcase sensor
I still have the same issue. any help would be appreciated.
Member
Joined: May 2017
Posts: 242
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From: West by god Virginia
'08 C300 4Matic Sport / '11 C63
I'd be looking at battery and ground connections too. Those codes tend to be PCM error codes which can influence timing etc.
Also, we assume a lot but since you had that type of work done we can safely assume all error codes were erased and came back?
Also, we assume a lot but since you had that type of work done we can safely assume all error codes were erased and came back?
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2009 Mercedes C300 4Matic sport, 2008 Chevrolet Suburban, 2002 Corvette Z06, 2002 Workhorse Monaco
catmandoob, Yes, cleared the codes and they all came back. Thanks for the help. I'll check the ground from body to engine. Do these engines have issues with the timing chain?
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2009 Mercedes C300 4Matic sport, 2008 Chevrolet Suburban, 2002 Corvette Z06, 2002 Workhorse Monaco
Thread Starter
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2009 Mercedes C300 4Matic sport, 2008 Chevrolet Suburban, 2002 Corvette Z06, 2002 Workhorse Monaco
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Thread Starter
Newbie
Joined: Jan 2022
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2009 Mercedes C300 4Matic sport, 2008 Chevrolet Suburban, 2002 Corvette Z06, 2002 Workhorse Monaco
Thread Starter
Newbie
Joined: Jan 2022
Posts: 8
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2009 Mercedes C300 4Matic sport, 2008 Chevrolet Suburban, 2002 Corvette Z06, 2002 Workhorse Monaco
Update
Car has been in the Mercedes shop for a month and they can't figure it out. They have been able to find the misfire and will run for a day then back to the misfire. Everything I replaced is what they would have done. Talked directly to the gentleman working on my car going over different sinerios and no solutions.
Joined: Nov 2016
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Actually, that was probably the best advice yet (except, don't swap out any more parts).
Related to potential grounding issues are battery issues. While it may seem unlikely, the Aux battery may not be performing as it should even though the voltage reading may be within limits. That would be the only thing more I would try before taking the car in.
Related to potential grounding issues are battery issues. While it may seem unlikely, the Aux battery may not be performing as it should even though the voltage reading may be within limits. That would be the only thing more I would try before taking the car in.
Joined: Nov 2016
Posts: 7,847
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Well, I see you did take it to a shop. A month? Did you ask them to swap out the battery? I bet they have the car on a trickle charger but don't put it back on the charger and after a day the battery drains back down. In which case, it could also be your alternator.
Has either battery ever been changed? If so, how long ago? These cars seem to be very temperamental when it comes to batteries and electronics.
Has either battery ever been changed? If so, how long ago? These cars seem to be very temperamental when it comes to batteries and electronics.
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2009 Mercedes C300 4Matic sport, 2008 Chevrolet Suburban, 2002 Corvette Z06, 2002 Workhorse Monaco
Update for Shop
Well, Got the car back from the Mercedes shop. They told me the old intake manifold internal plastic broke apart and pieces of plastic when through the cylinders. That is why I was getting random misfire codes. 1,5,6,3. Unfortunately, cylinder 3 did not recover from the damage and the exhaust valve has a spot on it where it will not seal and will cause an instance of low compression which in turn causes the misfire code for cylinder 3, but only when cold. They said it would need a new head. So... That is what I have been doing. putting another head on the car. I'll update this when I get it done.
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Joined: Apr 2008
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From: Walnut Creek, CA
325Ci, 325Cic, C300
That’s nuts! Seems very plausible given the known issues with the swirl flaps though. Makes me want to replace mine preventively. Currently at 191k on my 08.
And thanks for updating the thread. Wish everyone who posted questions did that.
And thanks for updating the thread. Wish everyone who posted questions did that.
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2021 GLB250 FWD, 2023 GLA250 FWD, 2013 C250, 2015 GLK350, 2005 ML350SE, 2003 E320
!!!
That “spot” on exhaust valve 3 must have been severe to require a new head. From the description “… only when cold”, I would have thought replacing the valve and dressing the seat would have sufficed.
That “spot” on exhaust valve 3 must have been severe to require a new head. From the description “… only when cold”, I would have thought replacing the valve and dressing the seat would have sufficed.
