My mercedes 190d wont turn off when key is removed

Question

hi can any1 help,

i have a mercedes 1991 190d and when i turn key off and take it out,my engine still runs,to get it shut off i 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.

Answer 1

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'll be fine otherwise.

Answer 2

A diesel engine runs on compression, so if the engine continues to get fuel while it's 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 I 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.

Answer 3

Typically, when the engine does not shut off, it means you have a vacuum problem, because when you 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 are expensive, therefore don't do this by trial and error. The best thing you can do for yourself is to buy a hand operated vacuum pump and check out all the vacuum hoses and connections. For example, there may not be enough vacuum in the system to shut off the engine because you have a vacuum leak in the door locking system.

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

Answer 4

There are 2 shut off valves on those diesels.  There is the one up by the injection pump and 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, you will need to see which valve is faulty ( this is the most common problem and 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.