mercedes 420 sec jerks when accelerating and stop

[Firepants78]

Hi There,

Today new problem occur

Driving by in the morning to work, after about 15 minutes of driving at the traffic lights, while accelerating car started to jerk at the next traffic lights, jerked and died.


Have any ideas where to look for the cause?

 

[ianrandom]

Didn't you have a new fuel pump relay already?

 

[Firepants78]

yes , brand new oem part

 

[design guru]

I had this issue in a 300SE and after replacing the fuel pump relay I needed a new set of HT leads as a couple had cracked the rubber cover and moisture from the cold was causing the problem. Try spraying the leads with some WD40.

 

[Firepants78]

Today the situation repeated, I noticed that so happens when it rains heavily, and a car is 2-3 days not used.
teeth to be certain what is damp can anyone give me exactly what components are responsible for the ignition in the car?
from what I think is this:
-coil ignition
-distributor
-rotor
-spark plugs
-HV cables

is there anything else I should check?

 

[ray_hennig]

Today the situation repeated, I noticed that so happens when it rains heavily, and a car is 2-3 days not used.
teeth to be certain what is damp can anyone give me exactly what components are responsible for the ignition in the car?
from what I think is this:
-coil ignition
-distributor
-rotor
-spark plugs
-HV cables

is there anything else I should check?

Yes, that you replace those items with new ones of the highest quality. MB original or Bosch/Beru.

I was tempted by cheaper cap and rotor and the rotor left me stranded for 2 hours while it cooled down. Replaced with MB parts and all's well.

RayH

 

[ianrandom]

Absolutely, especially the rotor. The leads are just too expensive from MB though, a few hundred quid all in, you have to buy the ends of the leads separately, meh. Euro Car Parts should have something half decent.

 

[grober]

Possibly condensation water inside the distributor body. [not cap] Everything normally OK at start up- then the heat of the engine block warms up the water which then condenses on the inside of the distributor cap causing a misfire. Try taking off the cap and giving the distributor body and cap a thorough dry out with a hair drier to see if that helps. this phenomenon is made worse by a rotor arm and cap that are past their best

 

[MphumiN]

I have the same misfire problems on my W203 C180 2004. It was caused by a sustained oil leak into my coil sockets because my tappet cover was worn out. I replaced the gasket cover and removed the oil/moisture from the coils. The car ran smoothly for about two weeks. Now the car is misfiring from cylinder 2 and 3 where most of the oil had leaked profusely. Is it possible that the oil leaks damaged the coils now they need to be replaced? The car is consuming fuel at a meteoric rate and its jerky.

 

[MphumiN]

I received the following error codes on the diagnostics:

P2004 - 48 -Altitude Pressure Sensor, Short Circuit to +120 (P0108) (P0107) (P0106)

P200B - 32 - MAF Short Circuit to +120 (P0103) (P0102) (P0101)

P201A - 32 - Misfire Cylinder 2 (P0335) (P0302)

P201B - 32 - Misfire Cylinder 3

The mechanic I spoke to said all these errors could have been caused by moisture in the engine, which turned out to be true ie.the oil in the coil sockets from the gasket cover leak.

 

[grober]

Can you tell us which engine you have M111 or M271? or putting it another way have you 4 ignition coils or 2 coils on your engine?

 

[MphumiN]

Thanks for the response. I have 4 ignition coils.

 

[grober]

That will make it a M271. Did you replace the oil seals in the coil recesses as well as the the one round the edge of the cam cover? Potential problems would arise from the coils themselves or the wiring harness which might be damaged.
M271 - oil in connectors? - Page 3 - Mercedes-Benz Forum