Technical Starting issues

[CK90]

Hi.
I have a 2003 1.9d that is refusing to start.
Starter motor engages for a split second then disengages although will continue to spin.
I have an intermittent red EML that i assume is related.
I have tested the starter and it is working as it should and have even tried a new one just incase.
Crank sensor has also been replaced and new battery fitted.
The car will start with a bump and runs well once going.
Any help would be appreciated.
Thanks

 

[AlwynMike]

Flywheel ring gear??
Was this checked when the starter was removed?

 

[CK90]

Flywheel gear has been checked is in good condition.
it cranks well for the short time it does spin but the solenoid wont stay engaged.
I feel it is electrical rather than mechanical. almost as if it is stopping itself from trying

 

[CK90]

i have checked and sprayed contact spray all connections and im getting 12v to the starter

 

[jackwhoo]

Check negative battery wire to engine/gearbox .
And both battery terminal clamps

 

[CK90]

all connections are good.
i've also tried running a new earth off of a mounting bolt for the starter but doesn't make any difference

 

[jackwhoo]

Check the main battery lead from battery to starter motor.

We're all the teeth around the whole of the flywheel ring gear examined?

It sounds as if some may be damaged/missing.

 

[AlwynMike]

We're all the teeth around the whole of the flywheel ring gear examined?

It sounds as if some may be damaged/missing.

Or the ring gear is broken/cracked and spins on the flywheel...