W210 E55 cutting out in traffic

[W210 Fan]

W210 E55 very annoyingly cuts out when the moving slowly in traffic, car moves along, cuts out, then a random combination of locking and unlocking or just turning the key restarts it,

any ideas?

 

[KLP 92]

Maybe a few possibilites, the 2 that come to my head are crankshaft position sensor or dodgy MAF.

 

[W210 Fan]

I thought about the crank position sensor, especially after the Maidenhead meet last year where the AA got called out! I had the MAF done at merc a while back...... will there be a fault code logged somewhere?

 

[Alps]

they say the crank position sensor doesnt leave a fault code but if you can replicate the problem whilst on diags it will momenteraly show one.

I still havent got round to replacing mine, it intermittently wont start when hot, and lately when left overnight, by what ive read this will lead to the problems you are haveing by cutting out whilst on.

 

[W210 Fan]

Cheers guys, for a few quid I can replace the sensor.... apart from on the crank line somehwere does anybody know where it is as there isnt a lot of room under the bonnet........

 

[Parrot of Doom]

Check for an air leak, I had a similar issue on my TVR. Is the idle stable?

 

[W210 Fan]

Idle is stable, brakes are fine so I assume the air leak is not on the vacuum side, should I be checking around the engine air inlet?

also would anybody have any idea of how to obtain the part number for the crank sensor on the web? would also be handy for the audi which needs a water and an oil temp sensor (I would say its all Bosch stuff) which is why I think the fuel consumption is worse than the mercs!

 

[Parrot of Doom]

The leak I had was on the plenum chamber somewhere, and would cause the engine to die randomly while idling at lights. Usually got worse when the engine was very hot.

 

[W210 Fan]

Been to Merc today and the problem was traced (after it cut out on the way to the garage and refused to start for some 15 minutes while a huge traffic jam built up behind me!) to a £5 air breather pipe for the crankcase, it is post MAF so when more air goes in then it should do the MAF doesnt know what to do so shuts down the engine,

thanks for all the suggestions guys