testing coil
#2
There should be resistance of several k ohms from the output to either low-voltage terminal, and less than 1 ohm between the two small terminals. Replace a coil that fails these tests, but the resistance test will misdiagnose a lot of bad coils as good.
With the key on, the low voltage terminals should both have battery voltage to ground. Test this in both the on and start positions. For the start test, disconnect the starter so the engine doesn't actually turn. Firing a Honda coil into an open circuit is likely to damage it.
Next to the "live fire" test, the only real proof. With the distributor cap off, hold a grounded test wire near the coil output and crank. You should get blue sparks that can jump 3/4 of an inch. If you have only weak yellow sparks, the coil is bad. If no sparks at all, it could be a bad coil, or something else. Also note that if the timing belt is stripped so the distributor doesn't rotate, no sparks will fire.
With the key on, the low voltage terminals should both have battery voltage to ground. Test this in both the on and start positions. For the start test, disconnect the starter so the engine doesn't actually turn. Firing a Honda coil into an open circuit is likely to damage it.
Next to the "live fire" test, the only real proof. With the distributor cap off, hold a grounded test wire near the coil output and crank. You should get blue sparks that can jump 3/4 of an inch. If you have only weak yellow sparks, the coil is bad. If no sparks at all, it could be a bad coil, or something else. Also note that if the timing belt is stripped so the distributor doesn't rotate, no sparks will fire.
Last edited by mk378; 05-16-2012 at 07:05 AM.
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