Hi, I've got an 82 240d manual 4 speed with 223k miles on it. I got it about 8 months ago and it's been running well for the most part but quite a few problems have emerged as of late.

The vacuum door locks were always slow to work since the day I got it. When I would lock/unlock the master door lock, it would take the rest of the locks a few seconds to lock/unlock from the vacuum. The rear drivers side door does not respond to the vacuum system in any way, same story with the trunk. So I'm well aware that I have a lot of work to do regarding hunting down vacuum leaks and testing the vacuum pump itself.

Last month, the car stopped turning off when I turned the ignition switch to the off position. I tried locking the master door lock from the outside after having removed the key from the ignition and it successfully got the car to slowly shut down in about 10 seconds or so. Now that trick stopped working and I have to push the linkage to the off position to shut down the fuel flow to get it off.

Now I say all this regarding vacuum leaks because I'm not sure if it could have affected my engine no longer turning over. The engine would shake quite violently when turning it off using the linkage stop or the master door lock (when it did work), so that may have thrown some connection loose.

Starting about a week ago, my engine started turning over more slowly when I would crank it, and not start slowly and idle rougher than it has in the past. This is immediately following a valve adjustment that I did. I feared that I adjusted the clearances poorly so I opened her back up and readjusted the valves. It indeed was incorrectly adjusted, and I spent much more time the second go at it to make sure after tightening everything that the clearances were all still proper.

The problem still persisted with the rough idle, cranking more slowly during startup, as well as a significant loss of power. I used to be able to get her up to 75 mph on the freeway no problem, now she has a really hard time getting up to 60 mph.

Then about 2 days ago she started cranking over severely slow, slow enough that I was frightened she might not start the next time I tried. So yesterday I get in and try to start her again and she turned a few times and then gave out. No cranking anymore period.

When I turn open the door, overhead lights come on, but when I turn the key to glowplugs-on, the glowplug light comes on, but overhead lights dim and flicker, and when I turn the key to on, only silence follows. When I let go of the key, there is a single 'click' noise, and that's it.

I was on a camping trip when this happened, not too far from home, and luckily I got it bump started and took it home. Now I'm not sure what to do. I tested the battery at the terminals with a volt meter and it read 12.3-12.4 volts.

If there's any other important information I can give to help diagnose the issue, I'll do so. Thanks everybody

Grab a Mityvac and check out your vac problems. This is what is wrong with all your locks and the engine cutoff. Not sure about the rest except it sounds like your battery is low. Maybe the alternator is not performing properly. Someone else should chime in about this.

Generally speaking you can solve your vac problems with a new actuator or two.

Kind of sounds like you have several problems.
Here is a link to the W123 vacuum system.

W123 Vacuum InterLock Diagram

On the rear of the Injection Pump (IP) is the Fuel Shutoff vac valve. There is a brown line going to it.
Off the main big black vac line that runs from the vac Pump to the Brake Booster are a couple other small vac lines. One will be another brown line.
This brown line goes to a valve on your Ignition/Steering lock assy.
When you turn the key to start the engine, the valve cuts the vac to the Fuel Shut off valve so the engine will start.
When you turn the Key to shut off the engine, vac is supplied to the shut off valve and the engine dies.

next to the Brake Booster is a bunch of other colored vac lines. The green one is for the Climate Control. Your yr 240d has two vac Pods it controls.
There could be a leak in this system.

There is a yellow plastic Check valve with one line going in and two yellow lines going through the Fire Wall.
One goes to the master switch in the Drivers Door.
The other lines goes to the vac Storage tank in the trunk above the Fuel tank.

This vacuum Tank is only to supply vac to the Door lock, trunk Lock and Fuel Door Actuators. It hold enough vac for 6 - 10 times to open and close the doors.

You have a vacuum leak some where in the system. You will need a Mity-Vac to chase down the leak/s.

You will need to isolate each system and see where the leak is. Use some Golf T`s to plug the rubber vac lines.
Start with the yellow line going to the yellow check valve. pump it to create the vac in the storage tank. then if it holds, and no leak, open and close the drivers door lock to see if the actuators work.
If not and you loose vac or one is slow, you have a leak. If a door does not work at all, a PO could have plugged off the door actuator.

Lift up the carpet on the drivers side. there is a black plastic cover and under it are a bunch of yellow lines with rubber connectors. yellow/red and yellow/green stripe. one is lock and one is unlock. Now it is just a matter of checking each door to find the leak.

Your starting issue could just se as simple as a bad ground. Make sure the cables at the battery are clean and tight. there is a ground strap on the drivers side from the bell Housing to the body. you can see it looking below the Oil Filter housing. accessed from under the car. remove and clean the connections.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works