C250 cylinder 3 misfire
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C250
C250 cylinder 3 misfire
ok, Im new here, Hello... I have this 2013 c250 and it keeps giving me a cylinder 3 misfire on my code reader, i clear the code and it comes back fairly quickly, I have swapped coils, replaced coils with used ones, swapped them and Im still getting the code, is it my wiring? I have also replaced the plugs with iriduim plugs, code reader says code is permanent..what does that mean ? so direction would be appreciated...thanks
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From: unbegrenzt
2017 GLE350 4MATIC
How many miles on the vehicle and how long have you owned it? Does it have a full service history?
Check cam position sensor and cam magnet connectors for signs of oil.
Check compression.
How is oil consumption? Rough idle? Smoke or steam coming from the tailpipe?
Check cam position sensor and cam magnet connectors for signs of oil.
Check compression.
How is oil consumption? Rough idle? Smoke or steam coming from the tailpipe?
Thread Starter
Newbie
Joined: Oct 2022
Posts: 5
Likes: 4
C250
7 years, 110k, I replaced the valve cover gasket because it had leaked oil into the #3 coil, and it was misfiring then , that how I found out about the oil in the coil, doesnt use oil, no smoke or steam, has rough idle because of #3 misfire, other than that, seems fine, dont know about compression yet
Out Of Control!!
Joined: Sep 2018
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From: unbegrenzt
2017 GLE350 4MATIC
If the coil was wet with oil, the connector could conceivably been saturated with oil. Open the connector and have a look on the harness side. Clean with contact cleaner. Also inspect the ECU connector for signs of oil on the pins. Clean with contact cleaner if oil is present.
Out Of Control!!
Joined: Sep 2018
Posts: 14,694
Likes: 4,584
From: unbegrenzt
2017 GLE350 4MATIC
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Thread Starter
Newbie
Joined: Oct 2022
Posts: 5
Likes: 4
C250
So I took it in, and they ran a compression test and said all is good, they came back to tell me that the new plugs I installed number 3 was bad, now here is where it gets to be a little weird, the reason I took the coils off was because #3 was misfiring, so when I did that I saw the spark plug hole filled with oil, so I ordered a new valve cover gasket and replaced it, so I thought I would also replace the plugs since they had 100k on them, so what are the chances that #3 would have the bad plug in it, seems to be odd. but it is running a whole lot better, I wont know for sure for at least a couple weeks if its fixed.
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