cl 600

[murray motors]

hi all i have a CL 600 V12 that was running like a dog computer said both banks had misfires so i put a near side coil pack in at £800 odd pounds and cancelled the faults car went great for a couple of days.Miss fire then came back on the off side only.So i put an off side coil on and cancelled the faults.Now the misfire is back on the off side only so new plugs and an air mass and still a misfire in all off side cylinders any body any ideas ???????

 

[biturbo]

check the cats, other than that there is something else like a control unit that can cause a misfire.

 

[Melk63]

I have heard of intermittent misfiring happen with quite a few v12 biturbos and the usual dealer advice is to change coil packs and spark plugs, usually to little effect. Do you find that if you turn the engine off for a few minutes and start again the cylinders fire properly again? If so, I agree with biturbo's advice above, check the cats.
Mel.

 

[murray motors]

i had a temperature probe at them but not a lot of difference in both kats it eventually cuts out and you restart it it goes slightly better.I had the kats in mind will have a look today

 

[AMGBlack]

Without sending anyone screaming for the hills, I had a SL600 Bi with the fault you mentioned above (about 5 years ago). . 145 days in total in the dealership in two years .. everytime it came out of the dealership would last 2 to 3 days and then die. . one bank packing up or engine management light on . (6 times the car cut out at motorway speed on junctions, thus making the car very dangerious). the dealership replaced almost everything except the loom, and in the end after much grief .. they took the car back and compensated me for my trouble . . They had MB look at the car many times and put it down to "god only knows" . . I hope you didnt get it ..

They should have Burnt it!

 

[RBYCC]

I have heard of intermittent misfiring happen with quite a few v12 biturbos and the usual dealer advice is to change coil packs and spark plugs, usually to little effect. Do you find that if you turn the engine off for a few minutes and start again the cylinders fire properly again? If so, I agree with biturbo's advice above, check the cats.
Mel.

If the fault clears on a restart, then the ECU may need to be reflashed..
Possible a newer version of software available?
I had a similar problem with a 2005 55K...
Dealer replaced coil packs, wires, and still under hard acceleration it would misfire and cause a CEL.
Shut it off, restart and all was fine..
Dealer finally discovered a Merc Tech bulletin about a ECU software upgrade to resolve the problem