S320 CDI W221 intermittent starting problem

[Dogma]

Hi All,

This is a great site and I thought I would write my first post to get some help from the experts on this forum.

I am experiencing intermittent starting problems with my S class. Eight times out of ten it will fail to start first time. After turning the key in the ignition (and holding) the engine with crank/turn but then cut out before cranking again and eventually starting. It has never failed to start but can take up to five turns/cut out cycles before starting. This happens irrespective of whether it is a cold or warm start.

So far the mechanic has tried the following:
- Replace the relay
- Replace the crankshaft sensor
- Tried starting using the spare keys to ensure there wasn't a problem with the main key.

None of the above has worked. Any advice would be gratefully appreciated.

By the way, not sure if it is a related issue, but I have noticed the gear change to be a little lumpy/jerky at times, especially in lower gears.

Vehicle details: S320 CDI, W221, 54K miles, 2007 model

Thanks in advance

 

[renrutp76]

Have you had any diagnosic checks run? Is rail pressure ok? is there any sign of air in the clear section of the fuel lines.

Hope this helps, best to get it checked on a Star diagnostic.

 

[Stability]

Hi All,

This is a great site and I thought I would write my first post to get some help from the experts on this forum.

I am experiencing intermittent starting problems with my S class. Eight times out of ten it will fail to start first time. After turning the key in the ignition (and holding) the engine with crank/turn but then cut out before cranking again and eventually starting. It has never failed to start but can take up to five turns/cut out cycles before starting. This happens irrespective of whether it is a cold or warm start.

So far the mechanic has tried the following:
- Replace the relay
- Replace the crankshaft sensor
- Tried starting using the spare keys to ensure there wasn't a problem with the main key.

None of the above has worked. Any advice would be gratefully appreciated.

By the way, not sure if it is a related issue, but I have noticed the gear change to be a little lumpy/jerky at times, especially in lower gears.

Vehicle details: S320 CDI, W221, 54K miles, 2007 model

Thanks in advance

Lets be clear before you head up the wrong path - you may have already !

Cranks but then cuts out - then restart it starts ?

What cuts out - the starter starting ?