And while ignition coil life may be compromised without a resistor, the additional secondary voltage (at the spark plug) is increased which generally improves power. So does your application require a ballast resistor? Quite simply, if your distributor has breaker points the answer is yes ; if not, the answer is no.
Why do I need a ballast resistor for a coil?
A Ballast Resistor is an electrical device that reduces voltage to the coil so that more energy is available for the spark plugs during starting . Why would a Ballast Resistor be fitted in a car? ... To counteract this distribution of energy, ignition systems were changed to use a 9v coil instead of a 12v coil.
Why do ignition coils need ballast resistor?
The ballast resistor allows the ignition system to operate at a lower voltage until the engine starts . ... The ballast resistor then functions to regulate the voltage going to the ignition system to avoid additional wear on the system.
What happens if you dont use ballast resistor?
If the ballast resistor is not working properly, the vehicle will not start . Since it is an electrical system, it is something best left to the professionals to handle. The only way to have the vehicle up and running again is with a ballast resistor replacement.
Why does a 12 volt coil need a resistor?
What is an external resistor on an ignition coil? The external resistor coils were used to boost primary ignition voltage during starting (making starting faster/easier). During starting, the external resistor is bypassed; once the starter is disengaged, power to the coil flows through the external resistor.
Can you bypass a ballast resistor?
The duty of the ballast resistor is to limit voltage to the ignition coil. ... A quick and easy way to diagnose ballast resistor failure is to bypass it by running a temporary jumper wire from the battery to the coil . If it starts and remains running, you’ve found the problem.
Is there a difference between a 6 volt coil and a 12 volt coil?
If you have an accurate ohm meter, reading across the posts of a 12 volt coil should be about 3 ohms. A 6 volt coil is about half of that . It is not an exact number, but close enough that you can tell 6 from 12 volt. Or, doing what Tom says, a 12 volt coil will flow about 2 amps if connected to 6 volts.
Does a resistor reduce voltage?
If a component in your circuit requires less voltage than the rest of your circuit, a resistor will create a voltage drop to ensure the component does not receive too much voltage. The resistor will create a voltage drop by slowing down, or resisting, the electrons as they try to flow through the resistor.
How many volts should my coil have?
The electrical system in your vehicle works on 12 volts , so every component must be based on 12 volts, as well. There is a wire connected to the ignition coil (known as a “hot wire”) that carries the 12 volts into the coil itself.
What causes a ballast resistor to fail?
The resistance through the ballast resistor varies with current flow which varies with engine rpm. This naturally causes the resistor to expand and contract from heat . That’s why they eventually fail.
Does a ballast resistor reduce voltage?
The ballast resistor, supplies the needed voltage during the start up, and then immediately after the arc is established, it reduces the voltage in addition to regulating the current flow .
What is the difference between a ballast and non ballast coil?
A ballast coil is designed to produce the same spark output, but with only 6 to 9 volts on the input. With a non-ballast coil, the input to the coil is the same, 12 volts , whether the engine is running, or being cranked by the starter motor.
How many ohms should a 12 volt coil have?
You should have a resistance reading of at least 3-4.5 ohms . A bad coil will show a higher reading then 3-4.5. Next, place the red or black lead from the meter to the centre of the coil , and to either one of the terminals positive or negative. You want 9500-10000 Ohms, a little less is ok but no more.
What Ohm ignition coil should I use?
Most ignition coils should have a primary resistance falling somewhere between 0.4 and 2 ohms ; however, refer to your manufacturer’s specifications for the correct reading. If a reading of zero is displayed, that signifies that the ignition coil has shorted internally in the primary windings and needs to be replaced.
How does a 12v ignition coil work?
An ignition coil is basically an electromagnet. ... The coil becomes a transformer, stepping the voltage up . If your car uses a 12 volt battery, the 12 volts you put into the primary side of the coil will exit the secondary side as 30,000 volts!
