Misfire misfire misfire. Can’t solve it. Need help
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Junior Member
Joined: Nov 2019
Posts: 40
Likes: 6
2017 c300 coupe
Misfire misfire misfire. Can’t solve it. Need help
My c300 has been misfiring and we changed everything from coil packs. Spark plugs and injectors. A compression check was also done and everything is good. I am about to give up on this because everytime I think the problem is solved it starts again. What else is left to changed? The battery symbol came up but I’m not sure if it’s due to the car being parked but do you think that can cause it? Mechanic was saying maybe the auxiliary battery needs to be changed. Also, someone else was suggesting it could be a bad ecu . Any help please
Last edited by hks; Jan 28, 2021 at 05:45 PM.
Senior Member
Joined: Feb 2018
Posts: 333
Likes: 102
2019 CLS450 (C257)
My c300 has been misfiring and we changed everything from coil packs. Spark plugs and injectors. A compression check was also done and everything is good. I am about to give up on this because everytime I think the problem is solved it starts again. What else is left to changed? The battery symbol came up but I’m not sure if it’s due to the car being parked but do you think that can cause it? Mechanic was saying maybe the auxiliary battery needs to be changed. Also, someone else was suggesting it could be a bad ecu . Any help please
Senior Member
Joined: Feb 2018
Posts: 333
Likes: 102
2019 CLS450 (C257)
so all coil packs, spark plugs, injectors were replaced with new original parts ya?
What were the individual number readout for each cylinder for the compression test?
Do you get random misfire of cylinder one when driving? or it's constantly misfiring till now?
Have you changed out any other parts, sensors?
battery symbol is likely due to the car being parked for long. you can drive the car around longer and see how it goes first. The aux battery (for us its a capacitor box) can be changed out easily if needed.
Lets see what else we can drill down to before looking towards a bad ecu.
What were the individual number readout for each cylinder for the compression test?
Do you get random misfire of cylinder one when driving? or it's constantly misfiring till now?
Have you changed out any other parts, sensors?
battery symbol is likely due to the car being parked for long. you can drive the car around longer and see how it goes first. The aux battery (for us its a capacitor box) can be changed out easily if needed.
Lets see what else we can drill down to before looking towards a bad ecu.
Thread Starter
Junior Member
Joined: Nov 2019
Posts: 40
Likes: 6
2017 c300 coupe
so all coil packs, spark plugs, injectors were replaced with new original parts ya?
What were the individual number readout for each cylinder for the compression test?
Do you get random misfire of cylinder one when driving? or it's constantly misfiring till now?
Have you changed out any other parts, sensors?
battery symbol is likely due to the car being parked for long. you can drive the car around longer and see how it goes first. The aux battery (for us its a capacitor box) can be changed out easily if needed.
Lets see what else we can drill down to before looking towards a bad ecu.
What were the individual number readout for each cylinder for the compression test?
Do you get random misfire of cylinder one when driving? or it's constantly misfiring till now?
Have you changed out any other parts, sensors?
battery symbol is likely due to the car being parked for long. you can drive the car around longer and see how it goes first. The aux battery (for us its a capacitor box) can be changed out easily if needed.
Lets see what else we can drill down to before looking towards a bad ecu.
Thread Starter
Junior Member
Joined: Nov 2019
Posts: 40
Likes: 6
2017 c300 coupe
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2013 Mercedes Benz C250
Hey guys I'm new to this forums just need some help.
2013 Mercedes Benz C250 - 55xxx KM clean as a whistle bought it brand new from the dealership
So I had a steering angle sensor changed to a after market one because one of the indictors broke off. Turned the car on every single light came on, drove it for a couple of weeks my car started jerking like it was mis firing . Took my car to a mechanic they replace my sttering angle sensor to a brand new one that cost me $2300 drove my car home and it still started jerking abit turned the motor off now my car dosent start at all it only turns to the reds Lights but not engine. can you guys please help me out .
churrrbro91 is online now Report Post
2013 Mercedes Benz C250 - 55xxx KM clean as a whistle bought it brand new from the dealership
So I had a steering angle sensor changed to a after market one because one of the indictors broke off. Turned the car on every single light came on, drove it for a couple of weeks my car started jerking like it was mis firing . Took my car to a mechanic they replace my sttering angle sensor to a brand new one that cost me $2300 drove my car home and it still started jerking abit turned the motor off now my car dosent start at all it only turns to the reds Lights but not engine. can you guys please help me out .
churrrbro91 is online now Report Post
MBWorld Fanatic!
Joined: May 2018
Posts: 1,432
Likes: 300
From: Illinois
2021 c300 Cab. Arrived 7/28/21 . 24 GLE 450e.
Hey guys I'm new to this forums just need some help.
2013 Mercedes Benz C250 - 55xxx KM clean as a whistle bought it brand new from the dealership
So I had a steering angle sensor changed to a after market one because one of the indictors broke off. Turned the car on every single light came on, drove it for a couple of weeks my car started jerking like it was mis firing . Took my car to a mechanic they replace my sttering angle sensor to a brand new one that cost me $2300 drove my car home and it still started jerking abit turned the motor off now my car dosent start at all it only turns to the reds Lights but not engine. can you guys please help me out .
churrrbro91 is online now Report Post
2013 Mercedes Benz C250 - 55xxx KM clean as a whistle bought it brand new from the dealership
So I had a steering angle sensor changed to a after market one because one of the indictors broke off. Turned the car on every single light came on, drove it for a couple of weeks my car started jerking like it was mis firing . Took my car to a mechanic they replace my sttering angle sensor to a brand new one that cost me $2300 drove my car home and it still started jerking abit turned the motor off now my car dosent start at all it only turns to the reds Lights but not engine. can you guys please help me out .
churrrbro91 is online now Report Post
Out Of Control!!
Joined: Sep 2018
Posts: 14,666
Likes: 4,568
From: unbegrenzt
2017 GLE350 4MATIC
Measure compression. Consider piston cracking as a potential cause for misfire. Read the posts on piston cracking.
Senior Member
Joined: Aug 2019
Posts: 284
Likes: 77
2019 GLC300, 2017 E300
Out Of Control!!
Joined: Apr 2019
Posts: 11,922
Likes: 6,775
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
multiple contributing issues
My c300 has been misfiring and we changed everything from coil packs. Spark plugs and injectors.
A compression check was also done and everything is good. I am about to give up on this because everytime I think the problem is solved it starts again. What else is left to changed?
The battery symbol came up but I’m not sure if it’s due to the car being parked but do you think that can cause it? Mechanic was saying maybe the auxiliary battery needs to be changed. Also, someone else was suggesting it could be a bad ecu . Any help please
A compression check was also done and everything is good. I am about to give up on this because everytime I think the problem is solved it starts again. What else is left to changed?
The battery symbol came up but I’m not sure if it’s due to the car being parked but do you think that can cause it? Mechanic was saying maybe the auxiliary battery needs to be changed. Also, someone else was suggesting it could be a bad ecu . Any help please
Do you have random cylinder misfire or one single cylinder ??
> Check your fuel trims value for negative values indicative of a lean (marginal lambda upstream sensor)
> Scan the car for list of ALL faults as some faults introduce TIMING LATENCIES > MISFIRE guaranteed!
> Battery low voltage is never a food thing around networked computers. Float your battery and try to keep an eye on alternator voltage. Multiple reasons can drain a perfectly good Benz battery.
> Do a quick "car reboot" to solve many weird computer issues such as discharge and misfires.
Let's *NOT* arbitrarily replace the ECU without any evidence because it controls the engine...
Last edited by CaliBenzDriver; Mar 13, 2022 at 03:37 PM.
Thread Starter
Junior Member
Joined: Nov 2019
Posts: 40
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2017 c300 coupe
I ended up doing a rebuild and this was my second one. For some reason the pistons keep cracking around the pin area. I ended up ordering some forged pistons from China and they been holding up.
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Joined: Jun 2012
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From: Toronto
2022 E53 AMG
Hello, I was looking at the video and I may know the issue. Firstly, you need to take out the Spark Plugs and check the gaps. Before you do any of this, you need to switch the coil of a working cylinder to the cylinder one. If the issue moves, then it's the coil but if the issue remains, then the coil is not the problem and the problem is the spark plug. So see if it's really the sparkplug and not checking the measurement. You can remove the sparkplug from the working cylinder and check it with the cylinder one for gap and then swap the sparkplug locations. IF compression is okay and all it good, you need to look at the injectors in cylinder one as it maybe stuck open or clogged.
