[Mgs] 78 B Running after the key is out of the ignition

[Paul Hunt]

North American MGBs with the ignition relay i.e. 77 and later rely on a
functioning anti-runon valve to shut down the engine by starving it of fuel as
a wiring design error results in voltage still being supplied to the ignition
system when the key has been turned off.  Any defects in the operation of the
valve or pretty-well anywhere in the emissions plumbing (blockages or leaks)
can cause this to happen.  UK cars don't suffer from it as they never had the
anti-runon system, the wiring error was discovered immediately and corrected,
but only on those cars.  The factory cure was to move the feed to the ignition
system from the output of the ignition relay (i.e. its contact) to its
winding, *and* move the feed to the ignition warning light from the relay
winding to its contact, i.e. swap the two wires over.  In theory either should
have done the trick, it's much easier to move the ignition feed wire as that
is only a matter of a couple of inches - once you have identified the wire.

PaulH.
  ----- Original Message -----
  Something I am noticing is, the car will not turn off all the time. I pull
  up to a parking spot, turn off the key and the car is still running.