Mercedes E350 Coupe 2010 Starting issues

[Timyr]

Hi, I'm hoping you can help me please. My Wife has an E350 Coupe. It's struggling to start in the cold weather. Initially I thought heater plugs although no warning lights and plugin detects nothing.

If I leave over night and then try to start first thing it will struggle to start. If I give it two "heats" and then leave the ignition on for another 5 seconds or so it will start ok. The 5 seconds seems to make more difference than anything because if I didnt use that delay or even go for a third heat it would still struggle. Any ideas please.

[sooty61]

Is it still on the original battery?

[Classy6]

Sounds typical of glow plugs on an old derv engine really. That would be my first port of call to check them manually, the glow plug control units were also very common to fail on the v6 diesels which would render all glow plugs dead.

Alternatively, it could be a multitude of things. Best off leaving it at a garage, making sure they have it overnight and from cold and letting them check actual values whilst it's trying to start. Could be anything from a intermittent crank/cam sensor, worn fuel pump/injectors to known fault with a software update.

[Candellara]

Hi

Had this issue with my ML350 - same engine.

Forget glow plugs - it's the glow plug controller at the front of the engine. Easy diy swap out. Part is about £150 IIRC

[Johnnybee]

I had to change the controller on my cls too. The symptoms on mine were extended cranking time and then a huge plume of smoke when it did start.