Poor cold starting

[JohnEclass]

Apologies if the question has already been asked!

But is there any known cold starting faults on E320 CDI's?
until the weather got cold my car fired up almost instantly, now shes taking 4-5 seconds of cranking before firing...... something to be worried about?
once warm fires up as normal,turn the key, let go and off we go. Only struggles first thing in the morning....bit like me!

 

[mersum1es]

It's usually fuel pressure problem. At cold conditions, injectors or hp-pump are leaking. Older CDIs have problem with low pressure fuel lines which brittle and/or o-rings of the lines allow system to draw air in system.

Then function of the glow plugs/relay will affect certainly (especially if we are talking about a bit newer engines, old inline engines are more robust).

 

[BlackC55]

It is very likely to be a faulty glow plug control unit.

 

[E280wilson]

Does the glow plug light stay on after starting.

 

[JohnEclass]

Does the glow plug light stay on after starting.

No light goes off as normal, think the fuel pressure might be the possible issue, assume
Can get checked at mercedes

 

[mersum1es]

Faulty control unit does not always show any indication about being faulty...

Fuel pressure test/leak test should be done at cold engine/conditions...