320 CE Hot Running Problem
 

Please help me with this problem.

I have a 1993 320CE (W124 coupe) with a hot starting / running problem.

The car has done 88,000 miles. It runs perfectly cold, after the first 5 - 10 minutes it can cut dead without warning. This can happen at any time - at idle or in full acceleration.

On cutting out I have to wait around 5 - 10 minutes. The engine will crank but not fire. After the 5 - 10 minutes it will restart and run perfectly again. Until the next time which could be 2 minutes or 2 days away.

The problem can also occur if the car is not running but the ignition is left on.

My record I believe is 9 cut outs in a day. I have gone for around 2 days without the problem occuring.

To date I have done the following:

Had the fuel system pressure tested - in workshop and on the road - OK

Checked control unit fault memory - nothing specific found

Had the ignition circuit checked completely

I have replaced

Fuel cap

Ignition wiring (low tension)

Engine ECU (albeit with a second hand unit)

Fuel pump relay

Ignition coils - the car has the ignition system with 3 coils and no distributor

Alarm & immobiliser



I believe this problem has taken years from my life. Can anyone help?

Do a search on "OVP"
...and then change it if it is the original....

Ok thanks for that I'll change the OVP tomorrow and let you know what happens.

It was the original OVP unit.

I changed it and ran around yesterday, gave it a few hot starts no problem.

Looks good, but I will re-post if the problem comes back

Thanks a million for your help. I'm a much happier man now.