7 Signs of bad ignition coil

The ignition coil is an essential part of the ignition system, which functions to create a high-voltage electric current of 20,000 to 30,000 DC volts which the spark plug will then convert into a spark in the combustion chamber.

The ignition coil consists of primary and secondary windings. The secondary winding will produce high voltage electricity (due to induction) when the electric current flowing in the primary winding is cut off.

This high voltage electricity is then converted by the spark plug into sparks so that it can ignite the fuel mixture in the combustion chamber to explode and produce engine power.

When the condition of the ignition coil weakens and is damaged, the sparks in the spark plug will also be disrupted so that it can cause various problems in the engine, ranging from vibrating to the engine stall. So how do you know a bad ignition coil?

In the following article, I will tell you about seven signs of a bad ignition coil that we know, see the full info below.

1. The ignition coil feels hot when we touch

The first characteristic of a bad ignition coil is that the ignition coil feels scorching hot when touched. The heat that occurs in The ignition coil feels different from the normal working conditions. Hot ignition coils are generally caused by several things, including the age of the ignition coil, the resistance value in the primary and secondary coils that are too large, and a short circuit in the ignition coil itself.

These conditions can cause excessive heat so that The ignition coil feels hot when held and will reduce its performance.

2. The spark in the spark plug is abnormal

The second sign of a bad ignition coil is an abnormal spark at the spark plug. The spark that appears on the head of the spark plug looks small, weak, and reddish yellow even though the spark plug used is still new.

A good coil will produce blue, intense sparks that look bigger when ignited. So, The ignition coil that emits reddish-yellow spark plugs is weak, and the spark is tiny, which can be a sign of a bad ignition coil.

3. An electric arc spark appears from the ignition coil body

The third sign of a bad ignition coil is that electric sparks appear in parts of the body or coil head. Electric sparks in the ignition coil body indicate that the ignition coil insulator has leaked.

To check it is pretty easy, use a spray filled with water, then spray it on the ignition coil when the engine is running (do it in dark conditions to see the sparks that occur). Ignition coils with good insulators will not produce sparks in the body, while bad ignition coils will throw sparks in some parts of the ignition coil body.

The high-voltage electric current that should only flow to the spark plug is finally divided into other parts where the leakage occurs. It will cause the spark generated by the ignition coil to be tiny, which is characteristic of a bad ignition coil.

4. Starter time to start the engine becomes longer (Hard start)

The fourth sign of a bad ignition coil is the long time to start the engine, which some people call a "Hard Start."

It happens because the pressurized air and fuel mixture is an insulator and cannot conduct electric current, especially when air pressure increases; a larger electric current is needed so that sparks can jump on the spark plug head.

A bad ignition coil makes sparking spark plugs in the combustion chamber more difficult. As a result, it will affect the starter time to start the engine, which is longer than during normal coil conditions.

Read Also:

• 5 Bad ignition coil symptoms
• How To Check Ignition Coils The Easy Way
• The Causes Of Carbon Fouling Spark Plugs

5. When the ignition coil is too hot, the engine is difficult to start

The fifth sign of a bad ignition coil is that the engine is difficult to start when the car coil is too hot. When the ignition coil is hot, the secondary winding cannot generate high voltage. It happens because when it is hot, the resistance in the secondary coil will increase and cause a blockage in the flow of electric current in the secondary winding, which also eliminates the spark to the spark plug.

In effect, the engine becomes difficult to start when the ignition coil is hot because there is no spark at the spark plug that should burn the gas in the combustion chamber.

6. The car engine vibrates, rough, and the idling is not stable

The sixth sign of a bad ignition coil symptom is the car engine vibrates, rough, and the idling is not stable. It can occur due to incomplete combustion in only part of the engine cylinder, while in some other cylinders, combustion can occur normally.

This condition will cause the engine to limp, vibrate and run unstable, which can be a sign of a bad ignition coil.

7. The car engine stall suddenly

The seventh sign of the bad ignition coil is that the car engine suddenly stalls. If the condition of the damage to The ignition coil is too severe, this can cause the car engine to stall unexpectedly.

Yes, a damaged ignition coil will make the ignition system unable to function even though the engine is still running at that time. As a result, the car engine will stall suddenly and cause the car to break down anytime.