Sounds electrical, like the coil still has some voltage fed to it. The
alternator, while it is still spinning, can potentially (!) feed some
current to the coil with the ignition off. But with the relative
resistances of the lamp and the coil this should only result in a very small
voltage across the coil, insufficient to maintain a spark (otherwise they
would *all* run on.
Some people recommend fitting a diode at this point, which I disagree with,
since it breaks rule No 1 - "It didn't have one when it came out the factory
and it did'nt run-on then".
With it running-on, measure the voltage at the coil and try pulling wires to
see if you can find one that makes it stop. On the other hand, the
anti-overrun valve may stop the problem, even though I believe its main
purpose is to stop Dieseling.
PaulH.
http://freespace.virgin.net/paul.hunt1/
-----Original Message-----
From: Speedo79@aol.com <Speedo79@aol.com>
To: mgs@autox.team.net <mgs@autox.team.net>
Date: 07 June 1999 20:33
Subject: 1977 MGB-Running on
>Greetings,
>
>I am having a problem with my 1977 MGB retrofitted with Dual SU HIF-4's.
>About a month ago, I gave my car a good tune up: new NGK plugs, wires, cap
>and rotor, the carburetors where running a little rich, so I leaned them
out
>just a little bit. The car runs beautifully, 23+ MPG, but with the coming
of
>hot weather the car has started to run on very badly. I am running 87
octane
>right now (due to price) but the gas here in Bakersfield, CA is of fairly
>good quality, and the car has not been overheating.
>
>
>When I turn off the key, the ignition light glows very faintly (as opposed
to
>glowing very brightly as it did before) and the car continues to run...I
>don't mean dieseling, I mean a slight miss, as if I could still drive it
>around the block. If I rev the engine, the car misses but revs easily
>(sometimes the engine will stall while I am revving, and then the engine
will
>diesel very badly) ...I have to let the clutch out with the tranny in gear
in
>order to stop the engine, and only then does the ignition light glow
>brightly.
>
>Please help me! I don't know what to do, and I can't have my car in the
shop
>this week.
>
>Thank you for all suggestions,
>Steven Sanchez
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