1986 190D wont stop running when turned off

[bwh]

My 190D wont switch off when I turn the engine off!!!

Someone said it is probable the fuel solanoid valve in the injector pump

If it is' is this expensive, and can I do it myself and what am I looking for?

I did have a look, but found 2 wires, one going into the top of a round thing about the size of a 2p on top of the pump,held in place by 2 torx. The other at the back and inaccessable!

Any help would be great

 

[Bolide]

AFAIK the shutoff is pneumatic on this car, like on the W124. Look for a broken plastic hose joiner, misplaced or perished hose or other air leak

There's a shutoff switch below the inlet manifold. It's below where the inlets bend apart (on a 250) - just put your hand down there and push the red lever

Does the headlight heigh adjustment work? On the W124 it's fed from the same vacuum system and is the normal cause of problems - often the vacuum pipe to the headlight gets displaced

Nick Froome
www.w124.co.uk

 

[wireman]

Bolide almost has it, I haven't found the headlamp leveling affected on any of the cars I have had to fault find on.

It is almost certain to be a leak.

Look around this lot and you will find some of my previous posts on this very subject (I dont have the time to find them).

Basicaly the engine pump evacuates the stop circuit and when you switch off the vacuum is applied to the pneumatic stop capsule which is mounted atop the delivery pump this will normally stop the engine.

When the key off and the engine running there should be at least 20"mercury of vac at the pipe to the capsule.

So there is a pipe from the vac pump that goes to the steering lock (via a small restrictor/non return valve) and another pipe from the lock to the pump. At the end of each plastic pipe there is a rubber joining piece, as Nick points out these can and do fail.

Try the vac gauge on the pipe at the steering lock, one of them comes from the engine pump and should always have at least 20"Hg vac.

If it does connect the pipes together and the engine should stop. This would be a fresh "switch" requried.

If it does not stop there is either a big leak, a dud capsule or (most unlikely) a stuck fuel pump stop mechanism.

Putting the gauge on a T connector would allow you to check the vac with all its bits connected.

Look at the manual stop lever as an assistant tries to turn of your engine does it gracefully descend or does it try and then return to its normal running position when the engine has finaly shudered to a stop?

On a good system the manual lever should go down, stay down and only return up once the key is turned to pos'n 3 (ign on) again, if it raises back slowly there is a leak. (Now mine is repaired it stays down for days.)

On my 124 it was the capsule having a tiny hole in it that made me gather the above knowledge, its an awkward pig to remove so pray for a leaky rubber joint piece.

As an aside,
Similar rubber joints are used to connect the transmission to the vacuum system and may be the source of some bad gear change behavior.

Good luck.