How to read DIS plug

[Graham Thackrah]

Hi Matt,

As per Haynes, the only temperature restraint is for checking the Hall
generator.

Check coil is in spec.

Disconnect DIS multi-plug, check voltage between contacts 2 and 4,
should be approx battery voltage with the ignition on.

Switch off ign and reconnect plug.

Disconnect multi-plug from distributor and check voltage at primary coil
terminals, should be at least 2 volts after ign on, falling after 1-2
seconds, with all that still hooked up, a jumper wire between middle
contact of dist. multi-plug and earth should make voltage hit 5-6 volts.

Switch off ign and check voltage across outer terminals of dist
multi-plug, switch on ign and check for 5 volts.

Hall generator should be checked after all that and with ambient temps
between 0 and 40 degrees celcius (32 and 104 F), disconnect central HT
lead and short it to earth. With DIS still connected, pull back the
grommet and hook voltmeter between terminals 3 and 6. Switch on ign and
slowly turn engine by hand. Voltage should alternate between 0-0.7V
(distributor cap removed) or 1.8V (distributor cap in place) and battery
voltage as you turn the engine.

Terminal numbers should be on the multi-plug IIRC. Only trouble you may
have is getting a probe in to the back of the DIS plug with it still
connected, keeping all that in place an then turning the engine, bit of
a juggling act that. Make sure you do get a probe in there properly, I
thought I had a faulty DIS when I just had failed to make contact with
pin 3 or 6. Engine should not be running for any test.

If I got anything wrong I am sure someone will chime in:)

hth,

Graham.