Ml320 Starting Problems

[adrian h]

My ML320 is playing up... in the morning no problems starts and runs fine
4 mile trip to office but if i use the car during the day or on my trip home
in the evening it will start but runs terrible, shuddering, missing if i stop and restart a couple of times it revs high for a little time whilst moving and then back to normal once it sorts its gearing out, i am not technical but find it a mystery tried starting without headlights on but no difference, a couple of years ago i had a problem with limp home mode and main Mercedes garage
had it in and found the problem to be water/moisture in the gearbox sensor so flushed gallons of oil through and it seemed to be fixed after nearly a grand bill, i wonder if this could be the same problem starting again :Oops:

any feedback will be helpful

Adrian H

 

[dogsbody]

You may have a problem with the journey length. Short journeys result in the engine not getting up to full operating temperature resulting in the engine management system, enriching the mixture - similar to a choke on carburettor engines. If the mxture is rich when the car is switched off, there is a danger that the system will backfire and destroy the cat matrix, so various ploys are used to prevent this, including some manufacturers prevent the car from starting until the mxture is clean air again. Other may muck around with the engine management system to make the fuel extra lean to compensate.
If this is a recent problem and you have been doing the same journey for a while, I would suggest that you need to check for error codes, and specifically for duff temperature sensors, which maybe are not working at all, resulting in the EMS over compensating the mixture. You also should look at the lambda sensor in the exhaust, as this also may be faulty.
What happens if you start the car and do a 20 mile journey - does the same happen then?

 

[adrian h]

thanks, on long trips never have a problem, tow a horsebox at weekends and travel miles and it never misses a beat this is why i find it a great mystery,
your comments could be the answer, how do i check the error codes?, does it have to go into Mercedes, also i remember the service guy when it went for a service commenting on a new fuel pump has been produced as the early ones had problems, long job he said have to remove seats etc but thought that it would be sensible to change at some stage..... could the fuel pump be dodgy...

Regards

Adrian

 

[dogsbody]

If the vehicle is OK on long trips but not on your short runs, I would definitely get the error codes check at a MB Stealership.
Still think that you have a sensor problem somewhere.
Unlikely to be the fuel pump, as your long runs do not give problem. Still think that your problem is either temperature or fuel mixture related

 

[adrian h]

it is gearbox problems again the seal has gone on the box and the connector
on the side, being replaced tomorrow at a non franchise specialist
The seals on the gearbox should last 50k but only 16k in my case..

still other than that problem everything else is fine......