C240 Engine Starts O.K. and then stops

[Bert]

Hi,
I have a C240 auto (2000). A few days ago I drove it to a destiantion with no problems. An hour later I tried to start it and it started first time but stopped immediately? I tried several times to get it to start and it just kept doing the same thing. After I left it for a few minutes it then started O.K.?
I also noticed a warning message "LIM" in the center of the display panel that I cannot remember seeing before!
My handbook makes no reference to this at all.
Has anyone got any idea what the problem might be?

 

[jberks]

Lim is the speed limiter so probably unrelated. No idea about the running though.

 

[dogsbody]

Lambda sensor

It may be that you have faulty sensor, and the system is shutting down as it sees the mixture to be too rich. Many cars have such software, and rich mixture is deemed to be a risk to explosion and damage to the catalytic converter matrix. Normally it is not a good idea to start the car and move it a few yards, as it wont start due to the rich mixture ... you have to move the car sufficiently far for it to reach normal operating temperature say a mile or so. However, you may have some sort of fault which is fooling the ECU, so it shuts down

 

[Bert]

Some Answers from Mercedes garage

Thanks for the input guys.
I spoke to the Chief mechanic at the local Merc garage who also said that "LIM" was the setting for the "Cruise control" and nothing to do with the problem.
However he was not so sure what the root cause of the problem was and suggeseted that I bring it to the Garage where they would hook it up to the diagnostics equipment to analyse.
My feeling is that I could end up paying out for mis-diagnosis from this process and still have the problem.

Has anyone had a diagnostics check and if so what are your comments about its accuracy?
I am tempted to just continue to use it (locally) until it happens again and then call out the garage.

 

[jberks]

Lim isn't the cruise control - its the speed limiter which was on. If you aren't sure about it, press the cruise control lever in, and it will switch off. Its a handy license protection / economy gizmo though.

The diagnostic will tell you what fault codes were recorded on the ECU. This assumes that the ECU detected a fault.
I doubt the mixture theory though as when a sensor errors, MB systems switch into default mode which in the case of a 240 makes it idle like a trabant and have as much power as an astmatic fiesta, but it does run and it does idle. Plus a restart generally cures it, at least temporarily. So, I suspect that as it didn't 'panick', it probably didn't detect a fault and there will be nothing to show.
It may be that something stuck in the throttle actuator and has freed off again, but this is a guess.

If she's running fine at the moment I think I'd keep my fingers crossed and leave well alone.

 

[piestore]

lim

HI

The cause of the problem is L5 crank shaft position sensor, fit a new one and forget the problem

 

[turnipsock]

I would suggest pulling off all the connectors of anything related to the fuel system and conecting them up again. It may just be a bad contact somewhere. The one under the manifold gives symtoms like you describe.

Can you start the engine with the throttle open and hold it around 2000rpm? Does the engine die when you lift off? Is there a smell of a really rich mixture?

 

[Bert]

Re: Crank shaft Position sensor

HI

The cause of the problem is L5 crank shaft position sensor, fit a new one and forget the problem

Thanks for this info. I remember now that the Mercedes Mechanic suggested that it could be this sensor as well. Do you know if it Is easy to replace?

 

[Bert]

I would suggest pulling off all the connectors of anything related to the fuel system and conecting them up again. It may just be a bad contact somewhere. The one under the manifold gives symtoms like you describe.

Can you start the engine with the throttle open and hold it around 2000rpm? Does the engine die when you lift off? Is there a smell of a really rich mixture?

Hi there,
thanks for your input and in answer to your questions when the car eventually started it ran absolutely fine and I was able to continue my journey home (some 30+miles) without any hint of a problem and there was definitely no smell of rich mixture although I haven't been able to get time to check under the bonnet since then but I will check it this weekend.