Hi all.

I have recently acquired a W203 C320 petrol , it has this hard start problem sometimes it will fire after 2 seconds sometimes I have to crank longer like 5 seconds before it fires up.

And when it starts sometimes it seems to run a bit lumpy for few seconds then all good.

Engine electric fan is always on( AC off) , wonder if has to do with coolant temp sensor ,

No faults shown on diagnostic Icarsoft.

Thanks

Simple thing first:
Make sure the airbox is pushed down all the way and fitted securely.
If the connection to the air intake in the back is not fitted tightly, it can cause the symptoms you described.

The next thing to check would be the starter and battery right?

Battery would be my next guess.

Starters don't fail slowly. They'll work now and not 10 minutes later.

With that said, my batteries always died within a day of giving signs of failure.

Coolant temperature sensor connector got a bit of a clean and that solved the fan issue.
new fuel filter solved the running problem

I see.

I see, sounds like we are making progress.