BMW 3 Series

[hellbell73]

My BMW 318i won't start from cold. Been on various diagnostic machines - nothing showing. Tried new leads, coil pack, everything. Has been suggested it could be the head gasket, although it's not losing water and the cylinder pressure is fine. Has anyone else heard of such a mysterious problem?

[BillyNoMates]

I have little confidence in garage diagnostic equipment. It doesn't initially sound like a head gasket problem but it could be any number of things. You say it's just from cold ? Sounds like a bad sensor somewhere within the ignition system.

Not sure how much you like to get you hands dirty but go back to basics ;

Check that you are in fact getting a decent spark to each cyclinder

Check that you have no fuel supply problems

Check that there is a decent airflow into the fuel injection system I.e. no clogged air intake or filter.

Get a decent workshop manual such as Haynes and run any checks that it suggests to test the electrical elements of the ignition system.