Hello everyone. This is my first post here at the MB Forum and I wanted to ask your opinion. I have a MB ML55 AMG -2000 which is not functioning very well at the moment. I have uploaded a video to youtube so please check it out and leave your comments here.

https://www.youtube.com/watch?v=J8-dH37DoI4

The car is idling roughly and shutting off. Engine is jerking/stalling and does not respond to throttle pedal, max rpm you can get sometimes is around 3000rpm... and power is lost etc. Anyone had similar problems with Mercedes?
Will appreciate your opinions. Yes I have read the fault codes and it doesn't seem to give a direct answer.

 

could be an air mass sensor, kinda sounds like it, possible clogged cats, fuel pump, could even be throttle position sensor but that wouldn't cause the car to idle rough. possibly a weak charging system, low voltage will do the same thing your car is doing.
What codes are you getting?
also in the video, towards the end, the tach, just sits at 0 while the engine is revving. to me it looks like a voltage issue.

 

Hi Chassis221, and thank you for your reply. Initially I got error codes for o2 sensor which I replaced all 4. After that the error code disappeared, but the problem persists. Also I got codes:
P1420
P1400
P0443
P0341 Camshaft position sensor (I guess), which I have changed and the code has disappeared (didn't help)
P0300 Misfire

I have also replaced the throttle position sensor with no cure for the problem. Also tried with a different crank sensor with no help.
Additional codes that I got with "iCarsoft" scan tool:
Most of them has nothing to do with the engine, but if there is anything that gives a clue what's going on?

B1002
B1089 CAn bus DTC stored (what is this?)
B1088
B1040
B1041
B1099
P185800
P178400
P114008
P100050
C1000 Control module - I guess this is BAS ESP when you remove the battery you get this? disappears when you calibrate the sensor by turning the steering wheel
P132010
P132000
P1817 Backlight KI.15 voltage supply error (DTC stored) (this is interesting?)

I have cleared the codes and didn't get them back anymore or maybe couple which I can't remember anymore which ones.

The car has new battery, if it is a voltage problem (which it can be) then the problem must be somewhere in the wiring?
"also in the video, towards the end, the tach, just sits at 0 while the engine is revving. to me it looks like a voltage issue. " Exactly, this is what I've been wondering too, why is it doing that? It is not responding to throttle pedal (as you can see in the video) but then suddenly it responds and goes up to 3000rpm (not more even it should) just like in the video and next it comes down and shuts down the engine.
I haven't got any fault code for air mass sensor (it doesn't mean that the problem is not there) but that's why I haven't changed it.

I'm not sure if it is possible to measure the coils with a multimeter, but I did and I got same measurements for every one of them, no discrepancies so I was thinking maybe the coils are ok? When I hit the cats with a rubber hammer there is no extra sounds, nothing is loose (that doesn't mean they are not clogged). Exhaust is coming out from the exhaust pipe pretty normally when you try by hand. Maybe i could remove the cats and try to start the engine? Any ideas/suggestions? Any ideas where to find wiring diagrams for this vehicle?
Thankx, will appreciate your comments

 

Yes, I would loosen the exhaust from the manifold and see how it runs.
Also after you've replaced some of those parts, you might need to clear codes and "teach in" the new part.
Check the 2 ground points on the fire wall. one on the passenger side and one on the driver side. just below the wiper arms. make sure the nuts are tight.

 

Hi Chassis221 and thank you for your reply, I appreciate it and sorry for the delay with my reply.
So finally got some time to play with my ML. I did what you suggested, loosened both exhausts from the manifold with same results.
No change at all except the loud noise. So I guess the cats are ok. Checked the groundings on the firewall and gave them some sand paper just in case. Also took out the EGR valve, cleaned it and checked that its working properly. Vacuum hose was broken, changed it but no effect.
Also checked all the coils, wires and spark plugs. One of my spark plugs were dead so changed it and now its working (even if you have one dead sparkplug out of 16 you won't even notice it).
I haven't changed the air mass sensor yet, but if I unplug the air mass sensor connector I will get an error code, otherwise no codes. I was also wondering about the throttle body itself? could that be the problem?
I think there is some electronics inside as well as potentiometers? I also took the truck for a ride and after warming up it worked little bit better. You could even get
4000rpm out . At the same time I got Missfire codes for cylinders 6 and 8, so swapped the coils from 5 to 6 and 7 to 8 but so far haven't got misfire codes...
Any suggestions?
Thanx for your input

 

Oh and forgot to mention that the fuel pressure at the pump is approx. 5.4 bar.
Don't know how much it is on the engine side...