vacuum system - PeachParts Mercedes-Benz Forum

lukemus53 · #1 10-09-2002, 10:01 PM

what going on with my '84300d?the last few days when i switch off igintion,engine continues to run for 4-7 seconds.also when i lock the car at the drivers door it only is locking the drivers door and the trunk.the other three doors do not lock.is the igintion tied in the door locks some way?thanks for your help, luke

#2 10-10-2002, 04:56 AM

I've got similar problems with my 300td at the moment, thankfully it's still shutting off and I'm not having to use the manual shut-off under the hood. I will direct you to my recent post and diesel don's reply which is excellent advice although I haven't had time to really investigate it yet.
You've got a leak somewhere in your vacuum system I'm sure.

#3 10-10-2002, 07:08 AM

You most likely have a leaking lock diaphragm at one of the other three doors, the fuel tank door or the trunk.

Start by opening the trunk and disconnecting the lines to the fuel tank door diaphragm and hold your fingers over them while you have someone lock the drivers door with engine running. If the other doors lock the problem is the fuel tank or trunk diaphragm, if they don't it is one of the door diaphragms. Just continue to check the vacuum as it goes down the line until you find the leaking culprit.

Good luck,

Stevo · #4 10-10-2002, 10:41 AM

My locking system was leaking and I started in the trunk, working fwd. Checked all the actuaters, finding all holding vacuum. When I checked the lines in the engine compartment found the line to the vent system was not holding vacuum. I learned allot about the system but I should have started in the engine compartment.

lukemus53 · #5 10-10-2002, 07:39 PM

thanks for your replies--now let me tell you the rest of the story.i called a friend today who also loves diesel mercedes.his first question to me was "has anyone been under the hood since problem started?"i told him i had changed the oil about a week ago [about the time problem started].he asked if i had moved any of the vacuum lines about.the answer was yes because on my car they are all very close to oil filter.i checked them all making sure they were connected.cranked the engine and everything is now working again.i'm glad they are working but do not have any idea which or where the leak was.i do have to agree that starting at engine and working back was the way to go,at least for me.