Although there are a number of suggested tests for the ignition coil while it is still attached to a car, the only accurate way of testing a coil is on a bench using a multimeter in the resistance setting. The ignition coil has two coils of wires, called windings. The meter quickly displays if either winding is bad.Know More
The primary winding collects the electricity needed to create the spark and the second sends it to the distributor. If either is bad, the coil is failing. Using a multimeter on a disconnected coil provides the data needed to determine its health. Start by checking the resistance between the coil's side terminals. With all but a few coils, the meter should show 0.75 to 0.81 ohms of resistance. Next, check the resistance between the center terminal and either side terminal.
A good coil reads between 10,000 and 11,000 ohms. Replace the coil if there is any significant deviation from these numbers. Cars with a bad coil often run or idle rough. During cold weather, starting the car becomes difficult. As the coil continues to deteriorate, the vehicle eventually fails to start. Replacing a defective coil helps the vehicle to start quickly and run smoothly, increasing its fuel efficiency.Learn more about Car Parts & Maintenance
A car igniter is a component in the car's engine that is responsible for sending a signal from within the distributor to the ignition coil, making the spark plugs fire. It is also known as the ignition control module.Full Answer >
Ignition coil failures are caused by worn out spark plugs that fail to transmit electronic signals in a functional and fluid manner. This creates a disruption in the regular flow of power across the ignition coil and makes the engine lose power. It is less common but still possible that the rotor the ignition coil rests on breaks and reduces the function of the power circuit.Full Answer >
Several tests can be done to test an electronic ignition coil, including a standard coil test, primary circuit switching test and ignition coil resistance. These tests will test the resistance felt on the ignition coil when it is connected to an outside power source.Full Answer >
Symptoms of a bad ignition coil include backfiring, bad fuel economy, and stalling and starting issues. Before the ignition coil is replaced, the engine will need to be properly diagnosed to ensure it is the root of the problem.Full Answer >