300td engine still runs when i turn key off.

[jgs600]

1990 mercedes 300td

my car has just develped a fault. when i turn the ignition off the engine still runs and wont turn off.
can someone point me to the problem
cheers

 

[BlackC55]

I can.

There is a shut off valve on the diesel pump that needs replacing. It looks like a bullet with a rubber tip.

 

[jgs600]

cheers for that , is it easy to replace and what parts do i need

 

[BlackC55]

Inlet manifold has to come off as well as the back of the pump. Take it to a diesel specialist if you are not sure.