Bad Ignition Coil

When things go wrong with the car, some problems are easier to diagnose than others. It’s easier to identify a flat tire than a bad ignition coil. Lucky for you, there are some symptoms that your ignition coil is failing or gone bad. Read on to find out if your ignition coil is the problem.

The Ignition Coil

The ignition coil is an electronic component designed for engine management. The coil is a part of the ignition system that converts the voltage into enough to jump the spark plug and ignite the air-fuel mixture. There are a few types of ignition coils: conventional, electronic, distributorless, and coil on plug. Conventional ignition coils are the oldest design.

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The ignition coil and the distributor make up the distributor system. The electronic ignition coil design came about in the 1970s where an electronic signal is sent to start the ignition. The distributorless ignition coils design is characterized by one ignition coil per two cylinders. A magnetic component changes the speeds. The coil on plug design is characterized by an ignition coil for each spark plug and uses the electronic signal.

Causes of Bad Ignition Coil

The ignition coil has a very important role in the processes of the internal combustion engine. When the ignition coil fails, it affects other components to the engine. Trouble with the ignition coil can come from different issues. Read on to find out what most commonly causes a bad ignition coil:

Wear and tear- All automobiles and automobile parts are subject to wear over time. Excessive wear results in

Bad Crankshaft Position Sensor – A symptom of a bad crankshaft position sensor (CPS) is when your engine will not start when you turn the key in ignition. This is because the ECU also depends on the crankshaft sensor for information about the ignition system control. There are two types of crankshaft sensor, the inductive (view on Amazon) and the Hall Effect (view on Amazon). The inductive crankshaft sensor generates an analog signal and may have one or two wires. The Hall Effect sensor is a ring of magnets leading into a rotating part. The sensor signals when it is time to fire the spark plugs. So, when the CPS malfunctions, the engine may crank but it will not start. If the CPS mounting bracket is damaged, the signal could deteriorate or completely fail, causing the engine to shut down.

Symptoms of Bad Ignition Coil

When something isn’t right with your car, there are usually symptoms that give you a clue as to what the problem is. There are definitely symptoms of a bad ignition coil. Here are the most common symptoms:

Check Engine light activatedThe Check Engine Light (CEL) on your dash may also activate to let you know something is wrong. If your ignition system has a problem, the CEL may activate. However, this light could be activated for more than one reason. An OBD2 scanner will give a more specific trouble code.

Misfiring/Backfire – The spark plugs ignite the fuel and air mixture in the combustion chamber. The ignition coil is not sending enough voltage to the spark plugs. When the plugs are dirty, damaged or undercharged, the air/fuel mixture is not lit in the regular pattern. The spark plugs are no longer useful. This causes your engine to sputter and misfire or backfire. When you are driving at higher speeds, you can feel the engine hesitate and then resume. The engine is getting some fuel, but the fuel delivery is not sufficient.

Stalling – Internal combustion engines stall for a number of reasons. The stalls can happen because of the ignition coil malfunctioning. The vehicle seems to start but doesn’t quite do it. This can cause real trouble. Not only does it mean that something is not working properly, because it is affecting your engine performance, you know right away that it is something important.

Rough idling – Your car may run with a failing ignition coil for a short time. However, during this time, the handling of your car will be rough. When you come to a stop, the engine will idle roughly. When stopping at a stop sign or light, you will notice that your car sputters as if it were going to cut off.

Hard Start/No Start – A symptom of a bad ignition coil is when your engine will not start right away when you turn the key in ignition. When the ignition coil malfunctions, the engine may crank but it will not start. If the coil is really damaged, the engine may shut down.

Poor fuel economy – When the ignition coil is malfunctioning, you will notice a significant drop in your gas mileage, as you will be going to the gas station much more often. Irregular firings in the cylinders mean that the system is injecting more fuel in response. The O2 sensor is not reading the behavior correctly and orders more fuel. Higher fuel consumption causes higher EGTs. The higher EGTs mean the system is not receiving sufficient air. That means you will only be able to go so far with less gas.

Oil leak – All leaks in the charging pipe continuously bleed pressure, creating an issue that the turbo must solve. The ECU configures the ratio of air to fuel in your engine. When leaking occurs, the configuration is inaccurate causing the turbo to work harder. Malfunctioning ignition coils tend to overheat and cause breakage in the wire coils. This causes an oil leak. The oil leak could also be caused by the mismeasurements of fuel for the spark plugs becoming eroded. The ignition coil is forced to operate at higher voltages as it is overworked.

Loss of power – A loss of power indicates that something is going wrong under your hood and that it is time for an inspection. In major cases, the vehicle may barely move at all. If your vehicle appears to struggle to accelerate, a bad coil leak may be the cause.

Preventing Damages to Your Ignition Coil

Most vehicle owners understand that a vehicle must be inspected and serviced from time to time, as referred to as routine maintenance. For those who don’t, the likelihood of problems that cause the ignition coil to go bad is extremely high. If the vehicle is not inspected routinely, small problems can escalate to major problems that are much more expensive to fix. This is also true for vehicles which sit for long periods of time.

If you want to avoid ignition coil problems or other issues and save $100s of dollars that you’ll spend at the auto repair shop, you’ll need to service your vehicle often – you can use our mechanic-rated Auto Maintenance and Repair Manual to do this. It’s basically what mechanics use to go through your vehicle to check if there are any problems that need fixing. As soon as they notice the most minor problem, they’ll ask you to fork out some money even though it’s a problem you can fix yourself in minutes – the manual will teach you how to maintain your vehicle every few thousand miles and it’ll teach you how to fix minor problems that mechanics will ask you to pay for; saving you money in the long run.

A lot of our readers have the Auto Maintenance and Repair Manual printed on their garage wall and 92% of them haven’t visited the auto repair shop in the last year because they know what to do to avoid problems. All it takes is giving your vehicle a little attention every few thousand miles and you’ll never spend money at the workshop again.

OBD2 Codes for Bad Ignition Coil

The OBD2 is a state-of-the-art diagnostic computer system that tells you why and when your automobile has trouble. The OBD2 Scanner is a standardized, handheld tool used to interpret the data gathered by the monitor. Some of the useful diagnostic information made available by the OBD2 includes rpm, coolant, road speed, and air temperature information.

If you have an OBD2 scanner (view on Amazon), look for the connector under your dash, on the left side of the steering wheel. The connector will be either rectangular or shaped like a trapezoid with 16 pins split into two rows of 8. Now that you can read the codes, here are some codes you should be familiar with pertaining to the ignition code:

Error Code P2335 “Ignition Coil L Secondary Circuit” code means there is misfire or some other problem with the ignition system that is designed with one ignition coil per cylinder. The engine control unit (ECU) has detected a problem in the ignition coil L. There are also other codes pertaining to the ignition coil L, to include P2333, P2334, 350, and P0362. The check engine light is activated and the code is thrown

Error Code P0351 “Ignition Coil ‘A’ Primary/Secondary Circuit Malfunction” code means there is a problem with ignition coil A. A primary or secondary circuit is damaged or gone bad. The ECU looks for specific signals to come from the ignition coil. When the ECU does not see the signals, the check engine light is activated and the code is thrown. This code is thrown primarily for the ignition coils; however, there could also be other problems that set off the code.

How to Test an Ignition Coil

If you believe the ignition coil is failing or has gone bad, there is a way to test it before you actually have it remove. Follow these simple steps to test your ignition coil:

1. Have someone handy to help you.

2. Turn your car OFF and let it cool down completely.

3. Lift the hood and find the ignition coil. If you are not sure where the coil is located, check your owner’s manual, call the dealership, or do an Internet search.

4. Remove one wire from the spark plug.

5. Remove the spark plug with a spark plug socket.

6. Attach the wire you removed back on to the spark plug.

7. Touch any metal on your car with the threaded part of the plug.

8. Remove the fuel pump relay.

9. Have the person turn the key in the ignition.

10. If there is a blue spark between the plug thread and the metal, the ignition coil is working. If there is no reaction from the contact, the ignition is probably not working.

How to Replace the Ignition Coil

The ignition coil is not so hard to replace. With a few tools, you can do it yourself. Just grab your owner’s manual and get the right ignition coil pack replacement for your car’s make and model. Once you’ve done that, follow these easy steps:

1. Turn your car OFF and disconnect the terminals from the battery posts. Tuck the terminals away or remove the battery.

2. Find the ignition coils for your car. Check your owner’s manual if you are not sure. In many cases, they coils are mounted on the engine.

3. Label the ignition cables and then carefully disconnect them. Tie the ignition cables together with a tie and also tuck them aside.

4. Unplug the ignition coil and remove the bolts or screws.

5. Remove the ignition coil.

6. Install the new ignition coil.

7. Reconnect the wires according to the labels you put on them earlier. Make sure the reconnections are accurate.

8. With the car turned OFF, reconnect the battery terminals to the battery posts.

9. Now turn on your car to see if the installation was a success. Give time for a few cycles to remove any thrown codes associated with the ignition coil.

Get an Inspection

If you don’t have a scanner or you are not too sure about the testing or replacing procedures, or you tried to replace the ignition coil unsuccessfully, you should take your car in to an automobile servicing center for an inspection. If you don’t have an OBD2 scanner, your mechanic shop does. When you take your car in for the inspections, ask them to check your ignition coil. If you have observed symptoms of a bad ignition coil before your car is due for regular maintenance, take it in anyway.

Safety First

Remember, safety first. Driving around in a vehicle with a failing or bad ignition coil is not only irresponsible, it’s unsafe. Think of your safety and the damage that is being done by you driving on it. What if your car breaks down while you are in traffic or out in the wild blue yonder? Be safe and thanks for reading.