525ixt Poor starting!!

[GM525]

Hello you guys!
Just like to say that although I am a Tech in UK, I am however a bit ignorant about engine management probs with my 93 525ixt mainly because in about a year of owning she's only missed a beat once - TODAY.
Basically went to start, turned over very fast as tho the comps were down and really took some turning over before she started - accompanied with a puff of bluey white smoke. Never had any probs with oil or coolant issues and has never done this before, so im inclined to dis-count head or valve seals. It seemed to me that it has flooded washing bores and therefore hard to start.
Personally I would suspect Coolant sensor or injectors leaking - but has anyone experianced this and found cure. Please note engine was stone cold when it occurred. thanks

[emw525E34]

Yikes, blueish white smoke is NOT GOOD!. Maybe fuel pump issues ?. You have not given much info, and I am also curious how you suspected Coolant sensor or injectors as the possible culprits ?.

If it starts, maybe should check the condition of your plugs too.