Sounds like: crankshaft position sensor.

Symptons : ignition failure. No fault codes. Random failure.

Fine wires inside crack with age and when warm will expand and break circuit.

Don't know cost but about £20 I guess so worth changing and seeing what happens.

Edited by madf on 29/10/2010 at 16:14

Yep, exactly where I was going. Really surprised the dealer did not change it. Regards Peter

ok changed the crank position sensor and all was good for about 50 miles. Went to start it tonight and same problem back again

I've asked one of the advisors on here as well and he replied with the following common causes for Mondeos cutting out :

1.Contamination of Air Mass Sensor. If this picks up any contamination then the temperature and cooling of the hot wire sensor will be affected and the mixture adjusted wrongly. I managed to get a small feather stuck to mine!!!!!, clean with a soft paint brush and be careful

2. Air Mass Sensor electrical connectors. These corrode and loosen very easily and can give all sorts of weird problems. Ford do a retrofit gold connecter kit for this. I clean mine regularly with WD40 and make sure all the contacts are tight. The clamps that go over the pins have habit of coming loose. I believe that is caused by vibration from the Ford Plenum. When I removed this for fitting a K&N the loosening seems to have stopped (I think the shorter plenum stub is better supported and vibrates less now)

3.Air Idle Speed Control Valve. This causes more than its fair share of problems and is a maze of small passages just waiting to get choked up. Either replace it (around £50 last time I asked) or first see if you can give the thing a good clean out (Petrol works).

I've had 2. checked out as well and theres no corrosion issues there.

Wondering if it could be releated to corrosion or damp/bad connection somewhere as I think every time its had a wont start incident it been cold and damp.

I'll look into the fuel pump wiring issue.

Are there any other electrical connectors/earths that are prone to corrossion ?

NB : got my laptop connected to the ODB port this time when wouldnt start. Running the ProScan software but not really sure what i'm looking for or if theres anything I could see. One thing i did check was the error codes : non-recorded.

Edited by kmidderigh on 09/11/2010 at 21:56

None of the above sensors/actuators would cause a cutting out and non start condition.I would be inclined to remove the unichip and see what happens.The engine management system on these is well proven and exceptionally reliable and in fact fairly crude compared to current models.hth

After cutting out and then restarting perhaps after much cranking, does it start cleanly or is it rough. Do you have a meter witha 10 amp current range. I ask this as a simple test is to remove the fuel pump fuse and measure the current whilst cranking. Regards Peter

tuning can greatly improve the driving experiance if done correctly - and usually after a lot of research. The ST220 is hard to tune - mainly due to the catalytic converters being housed within the exhaust manifold!

When I tune a car its not usually for outright power but to improve engine responiveness throughout the existing power range - this usually only results in a minor improvement to overall power. In my opinion the most needed adjustment to the ST220 is the suspension - its just to soft for a car that fast.