My 1986 560SL will run after the key has been turned to off. Turning
the key off and on has no effect on killing the engine or shutting
down the instruments. After a while the car will die on its own and
the instruments will as well turn off. It my take an hour or a few
minutes. After this the car will start and stop fine. The problem is
that it only pulls this stuff when away from our house and usually when
my wife has the car to herself so I have not been able to diagnose it
until last night when my wife pulled the car into the garage and it
kept running when she turned off the key for the first time at home.
With the engine running I removed the steering wheel, instrument
cluster and then was able to unplug the ignition switch. The car
continued to run while the switch remained unplugged. I then started
to investigate the relays located around and behind the glove box to
see what my be ingizing the engine ignition when suddenly the car died.
Much to my disappointment the car starts and stops normally now and I
now have no way to continue the search for the problem until it happens
again. I have looked over the engine wiring diagram and can concive
of several ways different relays could back feed the run terminal of
the ignition switch and there for am left to only guess at the problem.
I am hoping that someone who is familiar the ignition system in this
car can tell me what can keep the engine and instrument cluster
energized while the key is in the off position other then the key its
Thanks, Bruce Buchanan
I've heard about that, I believe they call it 'dieseling' here. I
believe I heard it's caused by (carbon?) deposits in the combustion
chamber that glow when the engine runs and keep it running even when the
normal ignition spark disappears. Or then again, maybe the ignition lock
is faulty ;)
Our three weapons are fear, surprise, and ruthless efficiency...
and an almost fanatical devotion to the Pope....
Its not dieseling, I am saying the care keeps running, gages and all
like the key is still on, but as I said the car keeps running with the
key switch unpluged, its not the switch.
Its somthing else sticking like a relay.
I have seent his before but not on a Mercedes.
I had one car where I was able to get home from work and be eating my dinner
before it turned off.
Then it might chug a few times and strat up all over again.
The only way to stop it definitley was to disconnect the battery.
That was in the days before radio key coders and complex electronics.
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