OK, so I took my car to 3 different mechs and none can find the issue.
SO when my car is cold (overnight) or at work when its NOT sunny the car is hard to start, BUT when its warm or stored in the sun its fine.
The Crank angle sensor and cam sensors have BOTH been replaced and the issue still Occours.
The car is NOT throwing any codes.

 

Sorry but without knowing your model its guess work for us .

 

Sorry its a 2006 S350L
A bit of extra Info I found out this morning after my struggle to start the car, ONCE it starts, I can turn it off instantly and start it again and it fires up immediately

 

A couple things to check and or replace, the fuel filter and the coolant temp sensor.
Or to start from cold turn the key to no 2 wait a few seconds, then try to start tye car .

 

I tired the waiting thing to start the car but still it fails to start
edit - i tried to wait 5 seconds 4 times this mornings and it started first off and now the dodgy mechanic says its the ecu

 

So i would pick up a good used ECU because they will be getting very rear soon . Not that expensive on Ebay .Just replace with exactly the same part number thats on the one in your car..i think he is right by the way .If its not the ECU it will come come it just in case .

 

Also note that there is NO check engine light on the dash at ALL

So do they need to be reprogrammed, or is it a case of taking the old out and putting the new in?

Also He said to turn to ACC for 5 seconds, turn off and repeat 4 times, and for the first time it started first pop, is that still the ECU?

 

If you dont get any information from this forum try joining another . I know nothing about yoir car only what i know in basic things .Google MERCEDES FURIM they will have a section just for your car.

 

Im just providing information, probably not the best thing on a help forum to tell other new people to go elsewhere

 

Well as lashton had posted on the 18 th of March , and he had no help from anyone . So you think Is ok for lashton to just sit on the forum waiting for a reply that never came . Just gave him some advice to ttry and help him .