Need help identifying multiple cylinder misfire on left bank

Ken Technician Georgia Posted   Latest   Edited  
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Driveability
2001 Mercedes-Benz CLK430 4.3L (113.943) 5-spd (722.6)
P0305 — Cylinder 5 Misfire Detected
P0306 — Cylinder 6 Misfire Detected
P0307 — Cylinder 7 Misfire Detected
P0308 — Cylinder 8 Misfire Detected
Misfire
Misfire At Idle
Missing Under Load

This vehicle is misfiring and is setting misfire DTC's (EDIT from Skip Codes) on the left bank after short run from cold.

To date, we've replaced plugs and wires and a left side cat converter.

Fyi, I'm Jim Fox, Ken … is the shop owner. We're going to see if we can change the name on the account.

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Missing Info
Missing Tests
Chris Diagnostician
New York
Chris
 

Skip codes? Are we talking about misfire codes? If so, is it a hard miss?

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Bob Mobile Technician
Illinois
Bob
 

Can you give some information as to testing? Codes with definitions, at Idle or under load, Fuel trim etc

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Scott Manager
California
Scott
 

Hi Bob, I'm working with Jim (Ken) on getting more info. Thanks.

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Steve Technical Support Specialist
Florida
Steve
 

If you are using the MB software there are some cool test procedures. The first one is the ability to monitor engine smooth running while either bank A or Bank B is shut down. Because the engine has two plugs/coils per cylinder a misfire can not be apparent when one circuit is failed and the other weak. Shutting off all the A plugs will increase the smooth running counts on a cylinder that was

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Terry Technician
United Kingdom
Terry
 

Hi Ken Check your AirMass sensor this will throw these codes along with P0300.

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Stacey Technician
Ontario
Stacey
 

Good Afternoon Steve Can you expand on where in the xentry software the tcc disable function is located. Was chasing a vibration last week on a 2010 ML350 and could not find it?

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Steve Technical Support Specialist
Florida
Steve
 

I would guess that would be under the activations menu in the trans Module. MB does move things around and some models like the ML have sometimes been slighted. if there is a lock up function separate it could be hidden there.

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Stacey Technician
Ontario
Stacey
 

Thanks Steve I looked pretty hard in the menus and did not see it. Vibration immediately goes away when you use the paddle shift to downshift. Pretty sure the converter has failed. It was a just purchased used vehicle so client was not real interested in extensive diag or repair time. Thanks again for the prepurchase advice on the xentry program. Still feel like a apprentice every time I get a

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Steven Mechanic
Washington
Steven
 

Hey Jim, It's hard to tell what you are describing exactly, but from this part of your post, "...left bank after short run from cold". It sounds like it begins to happen after is warms up a bit from a cold start. Therefore, I would suggest that you have an oxygen sensor that has failed and the ECM is trying to use it for feedback when it goes into closed loop. Check the oxygen sensor on that

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Steven Mechanic
Washington
Steven
 

Hey Ken, you got any more info to update us with? Did you get it figured out yet?

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