ML 270 CDi poor starting

[PaulD]

Hello everyone, a bit of help please with a problem that has been diagnosed with my 2003 model ML 270 CDi with 45k miles.
It has been running fine until recently when the weather got colder. It proves almost impossible to start when cold but the glow plugs were replaced only 9 months ago. It's never a problem when the weather is mild but the last few days it just won't start as normal when the outside temp drops below around 2 degs. It turns over without any problem (new battery 1 month ago) but it does seem to have a smell of raw diesel coming from it once it gets up and running and it's also a bit smokey when it eventually starts after about 5 mins cranking!
Anyway, my local garage has it now but they can't find any fault codes. They noticed a little bit of diesel around one of the injectors and they simply tightened it down more. They did however, tell me that it has low fuel pressure but don't know what is causing it
Any advice will be greatfully received and I might just have a bash at fixing it myself if it's not too complicated.

 

[Argenjagd]

Hi PAUL !!
I had the same problem a couples of years ago , when travelling 1500 km from my home place Bahía Blanca in the eastern side of Argentina to the west, in the Andes Mountains (Bariloche, the argentine swiserland), for skying.
As the temperature fell down from 30 Celcius to -10 C in the same day, the nex morning my ML270 cdi refuse to start. Once started and warmed up, it perform normally. And so every morning.
Coming back home I commented this with my mechanik :-?, he changed every O´ring in the engine fuel hose system (about 10, hose and pipes). After that and up to now it works perfect and never repeated that failure . ( Of course there were others)
As the guy show me, the old O´ring were dryed and sworn, allowing air comming into the fuel system, and dificulting the cold start.
One U$ dolar for ten O´rings and 20 U$ handwork.
Hope that help you in solving your problem, I would be glad to hear about that,
All the best,
Argentinische Jagdreisen