engine turn off (240D 1984)

[edds]

I have a 1984 A reg 240D the engine wont stop even after the key has been removed.

however if i turn the ignition on then push the drivers side door lock down then start it up it turns off fine.

The central locking dont work eaither so any help or tips would be greatful

thanks

 

[jberks]

You have a vacuum leak. The engine shut off is vacuum operated. So is the central locking so if you have a leak, I'd expect you'd have these problems. I bet your headlight aim adjuster doesn't work properly either. There are folk on here with far better knowledge of diagnosing the W123 vacuum systems than me so I'll leave the advice to them.

 

[edds]

You have a vacuum leak. The engine shut off is vacuum operated. So is the central locking so if you have a leak, I'd expect you'd have these problems. I bet your headlight aim adjuster doesn't work properly either. There are folk on here with far better knowledge of diagnosing the W123 vacuum systems than me so I'll leave the advice to them.

Thanks for the info. the headlight aim ajustment is working fine(it gose up and down) and the engine idle switch works when its warm. its just the central locking and engine stop thats not. so ant idears where to start or anything to look for would be a good help as its my first mercedes and its all new to me

Thanks

 

[TimN]

You have vacuum slave servers on the tailgate, petrol flap and three doors. There are two seperate vacuum circuits for opening and closing. From what you are saying the leak is on the open circuit. When unlocking the door you might notice a lazy lock. If it is not working at all the try it with the engine running. The extra vacuum created by the vacuum pump should overrcome all bar a major leak. The last lock to activate is prbably the faulty unit. If you can't identify it the way the the simplest is to remove each servo and examine it. Look for small splits in the rubber sheath arount the plunge shaft.

A new servo cost about £25 with the tailgate costing a little more. The rubber boots split an then leak. But to be fare it is after 20 odd years. You can rotate the connections on the servos and isolate the affected one on one circuit if you so that the central locking works in the lock cycle on all locks and works on all but the faulty one on the open cycle.