Re: 1941 Packard 160

Posted by HH56 On 2022/12/19 15:13:51

I know it is not that easy to do on a car with coils having the armored cable but when hot you might check the voltage at the coil terminal coming from the ignition switch before and then when the starter is cranking.

Assuming it is not a fuel issue such as a flooded engine, if there is something causing a large voltage drop and the voltage supply to the coil is significantly less than the 6.3 standing battery voltage -- down in the range of 5v or less -- when cranking, the spark could be so weak plugs are not firing reliably and the engine will not start.

Insufficient battery capacity, too small of cables, corroded, rusted, or age oxidized and otherwise dirty terminals, poor contact inside the ign switch and a dragging starter pulling excessive current have all been identified as causes of coil voltage drop. Badly adjusted timing is another cause of a lot of strain on the starter causing it to require high current and pull voltage down.