Could be many things but as a starting point.

1.  Remove fuel pipe feed to cold start injector - it's fed from the centre of the main fuel rail.  Place the open ended pipe into a suitable container and turn the engine over.  Fuel should squirt into the container.  This will confirm whether it is a fuel related problem or not.  No fuel - main fuel pump could have failed.

2.  If you have fuel then remove one spark plug.  Re attach lead to spark plug and ground the plug body.  Turn over engine and see if you get a spark.  If you do have a spark then this is good news as it not only confirms the ignition circuit is working but it also confirm the ecu is working as it is firing the spark plugs.

3.  If no spark then it could be an engine speed or reference sensor (both located on inlet side and are attcahed to the bell housing.)  Without these signals the ecu will not fire the spark plugs.  Could also be distributor rotor, cap, coil or main lead that is breaking down

4.  Could be ecu.  But do all tests above first and report back to the forum.

5.  Engine will fire and start even if the air flow meter is removed so it will not be that.

6.  Also the helper pump in the fuel tank can fail but again it will not give a no start condition.

Ian

Thanks for your help i have checked all things above and have no fuel or spark.i cant find fuel punp relay as the is M   different to the 635, i have also been told that the OBC control unit can stop it starting

Have you tried the main power relay - it has two contacts inside - one for the motronic and one for the dashboard and the rest - over time one of the contacts can fail sometimes leading to power to the dash and all that, but no power to the motronic so no starting.

Check for power at both output terminals of the relay, or at the motronic unit with the ignition switch on.

HTH

Sharkfan