What Does An Ignition Coil Resistor Do?

Can I bypass 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..

How do you test a ballast resistor coil?

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 do you test a coil?

Connect your multimeter to the positive terminal or pin of your coil, and to the high output terminal that goes to the spark plug. 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.

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 volts should be at the coil?

12 voltsMost electrical equipment works on 12 volts, but most modern cars have a resistor in the ignition system to assist starting. The coil in a ballast-resistor system is rated at 7-8 volts instead of 12 volts. When the starter motor is operating, the coil is fed with 12 volts from the starter.

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.

Do I need a resistor for my coil?

Pete, most coils need the resistor Although that’s not the case with EVERY coil, most do require it. The resistor limits the CURRENT going through the coil. Also, if you have a points ignition, it lengthens the life of the points greatly.

How do I know if I have a ballast resistor?

Registered. The resistor wire should be pink and have thicker insulation than normal wiring. Unless your car’s wiring was altered, it should have the pink resistance wire going to the coil.

Does a resistor reduce voltage?

A resistor has the ability to reduce voltage and current when used in a circuit. The main function of a resistor is to limit current flow. Ohm’s law tells us that an increase in a resistors value will see a decrease in current. To reduce voltage, resistors are set up in a configuration known as ‘voltage divider’.

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, less is on but no more.

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

6 volts systems use a coil with around 1.5 ohms between the two primary terminals. 12 volt systems have 3-5 ohms total,similar 1.5 ohm coil with a ballast resistor adding another 1.5 ohms. Or some 12 volt coils have 3-4 ohms built into them.

How many ohms should a ballast resistor have?

3.0 OhmsExternal Resisted Ignition Coils have an internal resistance of 1.5 Ohms and when combined with the Ballast Resistor you get a total resistance of 3.0 Ohms which is necessary for 12 Volt ignitions systems.

Where is the ballast resistor located?

Note: Ballast resistors are usually located bolted to the firewall if your distributor and/or coil is at the rear of the engine. If your distributor is located near the front or side of the engine in the case of an inline-4 cylinder, then it’s probably right near the ignition coil or distributor.

Do you need a resistor with a 12 volt coil?

If a 6 volt ignition system is converted to 12 volts and a Delco style 12 volt coil with an internal resistor is installed as part of the conversion, no external resistors are required. The 12 volt battery must be connected so the negative (-) battery terminal is connected to ground.

How do I test a 12 volt coil?

You can test a 12-volt ignition coil for effectiveness by checking the resistance of its wire windings with a multimeter.Disconnect 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.More items…

Can you bypass a resistor?

A wire in the left circuit is shorting the 100Ω resistor. All current will bypass the resistor and travel through the short. So typically the assumption of a short is done by redrawing the circuit. …

How do you wire a 12 volt ignition 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 do you test a coil resistor?

To test your ballast resistor you need an ohm meter or multimeter set to ohms. Remove the connectors from both sides of the resistor. The ohms should read between 1.8 and 5 ohms. You should be getting 9 volts to the positive side of the coil.

Does a ballast resistor need to be grounded?

A Ballast resistor should NEVER be grounded! One side of it will go to the 12 volts on The Ignition switch, The other side should go to the + side of the coil…

How do you wire a ballast resistor to a coil?

How do I Wire a Ballast Resistor & Coil?Disconnect the negative terminal of the battery, if there is one installed on the car.Route one end of the wire from the engine compartment into the passenger compartment. … Cut a piece of wire long enough to reach from the other terminal of the ballast resistor to the “Bat”, “+” or “B+” terminal of the coil.More items…

What is the purpose of a ballast resistor?

A ballast resistor is a device in your vehicle that limits the amount of current in an electric circuit. The ballast resistor is commonly found in older vehicles, because they did not have the benefit of circuit boards found in most of today’s vehicles.