[Spridgets] Ignition fault - Lucas electronic DM system

David Lieb dbl at chicagolandmgclub.com
Mon Jan 14 11:48:22 MST 2008


>>> From David says there is no obvious way to check the pickup is at fault 
>>> apart from during the 'few minutes of failure' ?
I can't remember what the tach does.

Unfortunately, the tach is your best diagnotic tool at the moment. Since the 
tach is monitoring pulses at the coil, if the pickup ceases to turn the coil 
on and off, the tach needle will drop like a rock, even though the wheels 
are still turning the engine. OTOH, if the coil stops generating the 
high-voltage sparks, the tach should still register, since the low-voltage 
side of the circuitry is still functional.

You could have a 12v test bulb with alligator clips that you could attach 
across the coil while it is down to see whether the switching is working. As 
a parallel load, it could affect the running of the engine, so I would not 
connect it until the failure occurred, although you could run the wires into 
the cockpit with a connector or a switch so that it could be "deployed" at a 
moment's notice. If your coil is easily disconnected, you could rush ut with 
a VOM and check the ohms across it with one side disconnected. Check it when 
fuctional for a baseline.
David Lieb 


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