Difficult Starting CLk 320 CDi

[Sprog46]

Previous owner had problems with difficult starting and all glow plugs were then changed earlier this year. I don't know if this solved the problem for him but I'm having the same difficulty now. Normally happens after car has been standing for a a couple of days and it then requires a second turn of the key before engine will fire. At this point some white smoke comes from the exhaust. The white smoke is not obvious at any other time and the coolant level has not changed!! There has been a suggestion that it may be caused by a loss of pressure in the fuel system - maybe a seal blowing?? Is this likely to be the cause and are there any other possibilities. It's going in for an inspection on Thursday so that may pin-point the solution but just wondering what thoughts are on the Forum.

 

[Thistle]

It's quite possibly a leak in a fuel line. This would allow air in which diesels don't like. A mechanic might loosen the fuel line at the injector then crank the engine to see if fuel or air bubbles came out. I woldn't though as it could be messy and risky with the pressures involved.
White smoke can often be diesel fog caused by incomplete combustion of the diesel vapour.

 

[WG M-B]

Sounds like the glow plug control module is not working

 

[t-dawg1]

Sounds like the glow plug control module is not working[/QUOTE

+1 as iv had the same issue on my OM642 exactly as you described and glow plug module cured it

 

[Sprog46]

Thanks for the replies. Let's hope it is just a leaky fuel line then cos I think a new Glow Plug Module (Relay??) is pretty expensive altho maybe I could perhaps get a used one from somewhere.

Any further thoughts anyone?

 

[BlackC55]

Don't buy a used one. They are not expensive. £118 IIRC.

The new one is modified.

 

[SL300-24]

Agree glow plug module....same symptoms as on my E 320 CDI....easy to fit DIY.


Olly do you know how the new plastic case ones have been modified?

 

[Sprog46]

I thought I sqaw somewhere that the new Merc modules were around £220! I' made some enquiries re 'used' ones and have been quoted £110 all in. It will be interesting to see what my German Car Specialist quotes me for new and installed.

Still think the leaky fuel pipe or seal sounds a better bet but tomorrow's diagnosis will tell, hopefully

Thanks for the comments though.

 

[WG M-B]

Leaking injectors will cause hard starting also on your engine but......
No white smoke

 

[BlackC55]

Agree glow plug module....same symptoms as on my E 320 CDI....easy to fit DIY.


Olly do you know how the new plastic case ones have been modified?

No idea. But the look very different to the original. I've fitted loads of them for this issue.