240d won’t turn off
 

Our 240d doesn’t seem to always want to shut off when the weather gets cold. This last week the temp dropped to the teens & twenty’s. More often then not turning the key would not shut down the car & would have to use the manual shut off under the hood. When the weather gets warmer such as today it shuts off. I’ve already looked over the vacuum lines and haven’t noticed any that are disconnected. Any ideas what else to check?

Thanks

What year is the car? If it is a 77 or later and the vacuum to the shutoff on the back of the injection pump is good when the key is shutting down, then the vacuum shut off is leaking vacuum internally, this is the most likely problem.

Do the door locks work ok? If yes then the vacuum supply is probably ok.

Do the brakes seem to have enough power assist?

Look inside the air cleaner to see if it is loaded with excess oil, if yes the vacuum pump (different from the shut off) diaphragm has failed.

It’s a 1982. Put a vac gauge on the main line and got 22hg which means the vac pump is working. Checked all the vac lines and connections which were all connected & looked to be in good shape. The car shut off every time today but the temperature is close to 50 degrees. It only seems to be a problem when the temp drops below freezing.

There is a vacuum shutoff valve attached to your steering Colum lock and then there is the vacuum shutoff valve on the Fuel Injection Pump.

If it keeps running you either shut it off with the Manual Shutoff Lever (under the hood) or disconnect and attach another hose at the vacuum shutoff on the Fuel Injection Pump and apply vacuum (some people have simply sucked on the added on hose).

When the Diaphragm inside of the Vacuum Shutoff Valve that is on the Fuel Injection Pump starts going bad it becomes porous and Oil passes through it into the Vacuum Hoses (you will find evidence of Oil inside of the Hose). I suppose when it is freezing if there is Oil in the Hose it is possible for that Oil to be too thick to allow vacuum to get to the Vacuum Shutoff Valve on the Fuel Injection Pump.

If it is the Vacuum Shutoff Valve on the Steering Colum Lock no one I can remember has reported a problem when it is freezing so when you find the answer to your problem it is going to be interesting.