Quick Answer: Do You Need A Resistor With A 12 Volt Coil?

Is there a difference between a 6 volt coil and a 12 volt coil?

You need to connect an amp meter in series with the coil and 6 volt battery.

A 6 volt coil will draw 4 amps.

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..

What is an external resistor on an ignition coil?

A resistance type wire is connected from the ignition switch to the ignition coil in the primary circuit. This RESISTOR (my caps) reduces the voltage at the coil from 12 volts down to a range of 8 1/2 to 10 1/2 volts under normal operating condtions.

How many ohms Should a coil read?

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 do you test a 12 volt coil with a multimeter?

How to Test 12 Volt Ignition CoilsDisconnect your engine’s main negative battery cable with a wrench.Pull the main ignition coil wire, the one that leads to the distributor, off the coil. … Turn on the multimeter and set it to the “ohms” function.More items…

What are the symptoms of a failing ignition coil?

Symptoms of a Bad or Failing Ignition CoilEngine misfires, rough idle, and loss of power. One of the most common symptoms associated with a faulty ignition coil is engine performance issues. … Check Engine Light comes on. Another symptom of a potential issue with the vehicle’s ignition coils is an illuminated Check Engine Light. … Car is not starting.

How do you wire a 12 volt coil?

How to Wire 12 Volt CoilsDisconnect the black negative cable on the negative post of the battery.Look at the ignition coil. … Connect one end of the spark plug wire to the large center terminal of the ignition coil. … Connect the positive terminal of the ignition coil to the “On” terminal of the ignition switch.

How many ohms should a 12 volt coil have?

Most ignition coils should have a secondary resistance falling somewhere between 6,000 to 10,000 ohms; however, refer to manufacturer specifications for the correct range.

How do you test a coil resistor?

Measure the voltage (or check with a test light) the voltage between the single wire and ground. If there is power there, the ballast resistor is likely bad. Reconnect the wires and measure the voltage at the positive side of the coil. If you see 8-13 volts, you may have a bad coil.

How does a 12v coil work?

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! The high voltage is carried away from the coil by a high-tension cable that looks like a short piece of spark plug cable and runs to the distributor tower.

Should negative side of coil have power?

The power from the ignition switch need to go to the plus side of the coil and the negative goes the the distributor on a 12v system. That should be opposite what it was on a 6v positive ground.

Does a distributor need to be grounded?

The starter, alternator, and most distributors are grounded through the engine block. If you have rubber, polyurethane, or painted motor mounts and no ground strap, you may not have a sufficient ground supplied to these electrical components.

Do I need a resistor for my coil?

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.

What does a ignition coil resistor do?

The ballast resistor allows the ignition system to operate at a lower voltage until the engine starts. After ignition, the alternator begins to recharge the battery, restoring the regular voltage.

How much voltage does a coil put out?

The voltage required is constantly changing and can vary from as little as 5,000 volts up to 25,000 volts or more. Some systems can put out as much as 40,000 volts under peak demand.

Does a 12 volt coil need to be grounded?

The coil does not need an electrical ground, but it does need a thermal ground for heat dissipation, meaning that the “ground” could be compromised by paint etc.