Problems starting corsa when engine is cold

[stacey28]

I have a diesel vauxhall corsa sxi 05 plate, when the engine is cold it takes at least a minute to start and i have to keep turning the engine over, it seems to be fine once it has started, but to get it to start I have to do this each time, also whilst it is starting there is thick black smoke coming out of it. I recently took it to my local car garage and they changed the spark plugs and the starter motor and no improvement in fact it has got worse, they said they had no idea what is wrong with it.
Any ideas what this could be would be appreciated.
thanks.

[Octane2097]

Firstly this forum is for B corsas an 05 plate would be a C.

FYI diesel don't have spark plugs ignition on a diesel is caused by very high compression but can only happen when the engine is warm enough.

To solve this diesel use glow plugs to preheat the engine when its cold if yours is failing to start when cold id get the glowplugs checked

Sent from my HTC Desire using Tapatalk 2