View single post by Tom Bradley
 Posted: 03-24-2018 03:14 am
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Tom Bradley

 

Joined: 07-15-2013
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 The additional wire to the tach should go to the coil connection that goes to the points. The voltage at this point should switch between 12V and 0V as the points open and close. The Spidya works by sensing these pulses.

Since you have points, you should also have an engine analyser that checks dwell and condition of the points. It is fairly easy to burn the points if they are left closed too long and too much current flows through continuously. You can also check for burnt points with the DMM. I think the spec is that the voltage across the points should be less than 0.2V when they are closed.

I suggest you make an ohmmeter measurement on your coils. Lots of the newer coils are designed for electronic ignitions and have very low resistance, which can quickly damage your points. The new coil's resistance should be about the same as the resistance of the old coil plus the resistance of the ballast resistor. There is a spec for the minimum total resistance for this, but unfortunately I don't remember it any more.

A quick sanity check could be to try starting the car with a quick-start spray and see if that works.

Tom