hi can any1 help,
i have a mercedes 1991 190d and when l turn key off and take it out,my engine still runs,to get it shut off l have to lightly press the throttle,sometimes it can take quite a few times to get it to shut off,all the vacuum hoes are fine and connected,thanks for your help.

The stop solenoid on the pump is faulty - just unbolt it & bolt in a new one.
In the mean time, you can stop it by stalling it, it will be fine otherwise.

A diesel engine runs on compression, so if the engine continues to get fuel while it is hot it will keep running. It sounds like you have a problem with the injection pump supplying fuel after the power is turned off.
Replacing hoses and seals on older injection pumps is a very common repair in the shop where l work, but if the problem is internal in the injection pump it could be expensive to fix. You should take it to the dealer for a diagnosis.

There r 2 shut off valves on those diesels. There is the one up by the injection pump & the second one is inside the vehicle by the steering column lock. They work by sending a vacuum signal to the pump to shut off the engine. You can also shut off the engine manually by pressing the stop lever on the pump itself.

To fix the problem properly, u will need to see which valve is faulty ( this is the most common problem & the injection pump shut-off valve is the most common of the two valves to fail ) or if there is a broken or kinked vacuum line in between the two.

Typically, when the engine does not shut off, it means u have a vacuum problem, because when u turn off the ignition key, vacuum will cause a valve to close off the flow of fuel to the injection pump. Be sure to properly identify the problem, because some of the components r expensive, therefore do not do this by trial & error. The best thing u can do for yourself is to buy a hand operated vacuum pump & check out all the vacuum hoses & connections. For example, there may not be enough vacuum in the system to shut off the engine because u have a vacuum leak in the door locking system.

It is not difficult to find the problem if u have the patience & tenacity. You can do it & save a lot of money over letting a mechanic check it out for you.