RNSL65

Strange engine problems.
My beloved car (Sl65AMG) has now got the following problem:
Cold startup is fine, driving around for approx one hour fine, full acceleration and driving is fine - engine ok! But then suddenly MIL light on and almost all power are gone + strange sound in the exhaust (like only 6. cyl. is running). Right side bank (6 cyl.) running fine, left bank, some or all cyl. not running correctly. The smell from the left tailpipes (left bank) is unburned fuel, the right pipe (right bank) is ok! The below codes are stored.
Switch off and on the ignition – or restarting engine does not change the behavior. But waiting approx 1 hour to cool engine down, it starts up fine, engine ok – nothing wrong, but then after ½-1 hour of driving the whole story repeats!
Please help!
P2050 Misfiring,damages TWC P0300Lamp&Stored&Current
P2057 Misfiring of cylinder 7,damages TWC P0307Lamp&Stored&Current
P2058 Misfiring of cylinder 11,damages TWC P0311Lamp&Stored&Current
P2059 Misfiring of cylinder 9,damages TWC P0309Lamp&Stored&Current
C1A00 ?
C1B00 ?
C1C00 ?
U3400 ?
P2043 Misfiring P0300Lamp&Stored&Current

TMC M5

I think you may have a bad catalytic converter. I think Sound8 mentioned that there was a recall in Europe on his CL65.

Tom

TMC M5

How many miles do you have on your SL65? It could be a problem with the spark plugs as well. MB spark plugs fire multiple times to make sure all fuel is burned...it may be a problem started at the plugs....then the unburned fuel gets into the catalytic converters and causes all kinds of havoc. I would check both out.

Tom

Oxygen

The codes and what you are describing sounds like EXACTLY what happened with my car (S600 V12TT) after I plugged in a newly tuned ECU...

Same codes, same smells, same sounds.

The problem? One of the 4 connectors on the ECU was loose, and only half of the injectors were firing because of it.

Recheck all the plugs on the ECU.

Let us know, good luck.

TMC M5

That is scary...

Tom

RNSL65

@TMC M5 - the car has 22000 miles on it, so I don't think it is the sparkplugs - With the ECI ignition system and spark plugs used, it should go at least 100.000 miles. That what I have seen on other cars with ECI.

@Oxygen - Sound scary if this is the case, I'll check right away and remove and reconnect all connectors on the ECU.

I'll let you know ASAP if this works! Thank you!

If anybody else has seen similar problems, please let us know!

RNSL65

@Oxygen - Did it drive normally until it was really warm as well?

JAYCL600

un plug your battery for 5 minutes and the symptoms should go away, if they dont then you may have some issues, my bet is that they go away after resetting your battery.

RNSL65

JAYCL600 – I understand your point, but please explain why this should make the problem go away? I know you will make a hardware reset on the ECU by doing this, but……?
Which battery should I disconnect, the front or back battery?

Oxygen

No, no normal operation at all. As soon as you start the engine it would only run on half the cylinders.

RNSL65

I have now tried all the good advice published here (i.e. replug the ECU, unplug battery etc.) It’s still same symptoms, that is cold driving normal for up to one hour, then left bank more or less disabled, wait an hour, the engine run all 12 cyl. Again!
Resetting the ECU only brings the same codes next time it fails again!
P2050 Misfiring,damages TWC P0300Lamp&Stored
P2057 Misfiring of cylinder 7,damages TWC P0307Lamp&Stored&Current
P2058 Misfiring of cylinder 11,damages TWC P0311Lamp&Stored&Current
P2059 Misfiring of cylinder 9,damages TWC P0309Lamp&Stored&Current
P205A Misfiring of cylinder 12,damages TWC P0312Lamp&Stored&Current
P205B Misfiring of cylinder 8,damages TWC P0308Lamp&Stored&Current
P205C Misfiring of cylinder 10,damages TWC P0310Lamp&Stored&Current

TWC = Triple Way Catalyst
Maybe it’s time for the dealer to step in!

RNSL65

I’ve done some measurements on the ECI system - output from ECI power supply (before the coil pack).

Then the fault are present (left bank of cylinders not running correctly) the 180V and 23V output from the ECI-Power supply to the left coil pack is missing. When engine runs normally (after approx one hour switch off), the 180V and 23V are back on!

This should indicate a bad ECI power supply, but I don’t know if the ECU tells the ECI-power supply to shot down?

RNSL65

I've now done a ECI power supply rewiring, swapping the 180V & 23V power from left to right bank and vice versa. The faults are present, the left bank coil still shows up to be the faulty one!
StarDiag tester showed the same error codes as my EU702 tester did!
Next move is a new coil for the left cyl. bank!

RNSL65

The dealer diagnosed it to be the ignition coil unit, and changed the unit, but the fault was still present! Then the ECI power supply was changed, and now the fault is gone. This also is the logically solutions to my measurements where the 23V and 180V was missing!

IngenereAMG

I had a feeling that was your problem. Good job!