ML 270 CDi low fuel pressure

[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.

 

[astradave81]

a lot of modern diesel cars have an in tank fuel pump if the car uses an electronic style diesel injector. Sometimes these pumps can completley stop working and the car will still run but just make it difficult to start when cold. Suggest this to your local garage and they should be able to test it for you.
If they have the correct diagnostic equipment they should be able to perform an "actuator" test and you should be able to hear the pump running when so selected. (thats if they turn the radio down)

 

[ML270BZ]

paul,

in reference to your ML 270 having difficulty starting and after 5 minutes of grinding the starter it eventually starts but with raw diesel smell and bit smokey.

From my experience, after changing all my glow plugs, I found out that my glow plugs weren't getting any electricity and as such the difficulty in starting. I was told that when you keep trying to start eventually it warms the head and the engine will start. The problem with this is that you are killing your starter. I had to order a Glow Plug Relay which by the way, sits on the right side of the engine bay behind the fuse box (the back half of the fuse box). have a electrician do a check to see whether the relay is working.
good luck.

 

[star]

Doubt it will be glows as cdi's can start without them working, how is he checking the fuel pressure, on star? check for injector leak off, fuel regulator "o" ring in fuel rail or high pessure pump. might sound stupid, but check right fuel is or has been put in??