What should the voltage be at the coil?
To check that voltage is reaching the coil, connect the voltmeter between the + or SW terminal of the coil and earth, and switch on the ignition. The meter should read nearly 12 volts, or about 7 volts if the coil has a ballast resistor.
How many volts does a distributor need?
The battery supplies twelve volts of direct current. In order to achieve combustion, though, there needs to be about 40,000 to 100,000 volts at the spark plug. How does the voltage get so much higher? The answer lies in the ignition coil.
Should coil have 12 volts?
It should have approx 12 V with the key on. Either there is a bad connection upstream, or the wire is shorted (it is not fused).
How does a distributor get power?
The distributor is what gets that high voltage from the coil to the right cylinder. The connection is accomplished through a cap and rotor. The ignition coil connects to the rotor, and the rotor spins around inside the cap.
How does the ignition coil work in a distributor?
The battery provides low voltage electricity to the ignition coil. The ignition coil converts the low voltage electricity into high voltage power in timed pulses. The distributor has a shaft that gets spun by the camshaft.
How many amps does an ignition coil draw?
Usually 10 amps or less – the wires to the coil tend to be 14/010 same size as used for indicators etc. See some detail here: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/ignition.html [How a coil works] [1] I read that modern coils draw about 4 amps while the points are closed.
Can a weak ignition coil cause under hood havoc?
(Positive ground is the reverse.) Most ignition coils are long lasting and reliable, but a weak coil you can be the cause of under-hood havoc. You cannot operate a car smoothly without delivering high voltage to the spark plugs to ignite the air-fuel mixture.
What to look for in an ignition coil?
However, it is more common for coil problems to show up as hard starting, a repeated high-speed miss or a gradual decline in ignition system performance. Coils can be tested with an ohmmeter (most coils will give a reading around 8,000 ohms) or with the small scope on a Sun machine.