Can a Bad Alternator Cause a Misfire? 8 Signs That Your Alternator is Failing

Faulty electrical systems caused by an old alternator can cause problems such as misfiring engines, power windows not working, and even a dead battery. Read this post to find out all the warning signs and learn more!

All gasoline or diesel-powered vehicles comprise a key component called an alternator which works with the battery and provides power to all the electrical accessories in the car.

But can a bad alternator cause a misfire?

It’s rare for an alternator to cause a misfire. For example, the bad alternator cannot produce enough electric current in the spark plug to ignite the air-fuel mixture, so misfiring occurs.

Can a Bad Alternator Cause a Misfire

What Are The Signs Of A Bad Alternator?

The average life span of the alternator is 100,000 to 160,000 miles, which, on average, one can drive in about seven years.

If you are using an older than 7-year-old vehicle and notice the symptoms below, there can be issues with the alternator.

#1. Headlights Getting Dim And Then Becoming Bright

A faulty alternator can cause car headlights to get dim and then again become bright. It mainly happens because of voltage variation.

#2. Dead Battery

The alternator keeps charging the battery when the vehicle is in running condition, and it further provides power to all the car’s electrical components.

But when the alternator fails, then it results in a dead battery.

If you are using a car battery that is less than two to three years and it’s becoming dead after your car runs for a few kilometers, then there is probably an issue with the alternator.

#3. Burning Smell

Alternator failure can cause a burning smell inside the car.

When the alternator fails to function, all the internal components inside the vehicle are overheated, and the cables may begin to burn.

If it smells like rubber, then most probably, the alternator belt is burning.

#4. The Engine May Stall

The alternator provides power to the sparkplug and ignition coil. But when it cannot provide power, the engine stalls or shut down.

You may think the issue is with the spark plug or ignition coil. But the actual culprit can be the alternator.

#5. Slows Down The Electrical Systems

A bad alternator cannot charge the battery; hence, all the electrical components like GPS or the entertainment system inside the car will slow down its function.

#6. You Can Problem In Starting Your Vehicle

Alternator issues can create starting problems in your car. It happens because the bad alternator cannot give the proper amount of power to the battery.

#7. Battery Warning Light Activates On The Dashboard

One of the obvious signs is the battery warning light activated on the dashboard. It not only tells you about the low battery but also about the bad alternator.

A good alternator always produces a voltage of 13 to 14.5 volts.

But when it produces an output voltage less than normal, the sparkplug and other components will require more electric current to function properly. Hence the battery will drain out its charge faster.

#8. Check Engine Light Gets Triggered

Activation of the Check engine light is the next warning sign of a bad alternator.

The alternator provides power to various electrical accessories inside the car, and issues with the component may cause huge problems while driving.

Triggering of dashboard light is a way to inform drivers about issues with the alternator or any other significant components inside the car.

It’s best to stop driving and check the alternator and the car battery to ensure they are working in good condition.

If they are working well, there can be issues with other car components, which cause misfiring.

How Can I Know That My Alternator Has Gone Bad?

#1. Disconnect Alternator

Your first task is disconnecting the alternator and running the vehicle for almost 10-15 minutes. The battery must have a good charge to run your car.

Additionally, you need to switch off all the electrical components like lights, power windows, and the entertainment system at this time.

If there will become no misfire, then there can be problems with the alternator.

#2. Multimeter

A multimeter is a device that helps measure any electrical component’s voltage.

You need to switch off the vehicle and put the probes on the battery terminals. The voltage reading should be within 12 to 13 volts.

If the multimeter shows this reading, turn on your vehicle and again check the reading. The voltage this time must go above 13 volts. But if it stays constant, the alternator can have problems.

You can even switch on all the electrical systems and check the battery voltage.

The alternator functions appropriately if the reading is constant or becomes low. It cannot take a load of various electrical accessories inside the car.

#3. OBD Reader

You can hook your vehicle with an OBD reader and check the error code. If it’s showing a P0562 error code, the car alternator is having a problem.

What Can Be The Other Reasons For Misfiring In My Vehicle?

If you have checked your alternator thoroughly and it’s working well, then there can be other reasons for misfiring in your vehicle, which is listed below.

#1. Malfunctioning Of Ignition Coil

The battery voltage is very low and insufficient to produce an electric current in the sparkplug. So there comes the importance of the ignition coil pack.

It comprises an iron core, and primary and secondary windings are wound over it.

The primary windings are on the outer layer, and the secondary windings lie on the interior and have almost 21,000 turns.

When you provide power to the primary windings, an electric current starts flowing, generating magnetic flux and finally producing a high voltage in the secondary windings.

The secondary windings are connected to the distributor, which then disturbs the voltage to the sparkplugs in your car.

The voltage generated by the ignition coil is sufficient to produce electric sparks in spark plugs.

But when the ignition coil pack goes bad, the electrodes of the sparkplug fail to produce a proper electric spark, resulting in misfiring.

#2. Problems In O2 Sensors

Modern cars are equipped with the latest four oxygen sensors, and their work is to measure the oxygen present in the fuel mix and send the information to the ECU.

The ECU then adjusts the air-fuel mixture accordingly so there will be no misfire.

But defects in O2 sensors can send wrong information to ECU, resulting in a misfire.

#3. Problems In Crank Position Sensor

The work of the crankshaft position sensor is to monitor the speed of the crankshaft and sends the information to the ECU. The ECU then controls the fuel injection accordingly.

The sensor gets powered by the alternator. But if there is a fault in the crank position sensor, it can result in misfiring.

#4. Bad Fuel Injector

The work of the fuel injector is to provide the proper amount of fuel inside the combustion chamber. But when it goes bad, it can provide adequate fuel, resulting in misfiring.

#5. Faulty Sparkplugs

The spark plug wires or electrodes can get damaged with time and, hence cannot provide a spark at the correct time. It finally results in misfiring.

Frequently Asked Questions

What problems can a bad alternator cause?

If the car alternator stops working, it will not be able to charge the battery when it is in running condition. Hence, the battery charge can slowly decrease, resulting in a dead battery.
The car’s electrical components will stop functioning, and the engine can even shut down.

What are the symptoms of a bad alternator?

Here are some of the symptoms that you will face if your alternator is failing:
Dead battery
Starting problems in the vehicle
Battery warning light on the dashboard
Check engine light
Odd sounds
Burning smell.

Can a bad alternator damage spark plugs?

The alternator provides power to sparkplugs. But when the alternator sails to work, it cannot power the sparkplugs.
Hence the sparkplugs will not be able to ignite the air-fuel mixture inside the combustion chamber.
Finally, that results either in misfiring or, in the worst cases, the engine may stall.

How does a car act with a bad alternator?

If the alternator goes faulty, your car will have starting issues, or in the worst cases, you will not be able to start your vehicle.
Your car’s lights will also start to dim, and all the electrical components will start to work slowly.

Can a bad alternator cause a loss of power?

Yes, a bad alternator can cause a loss of power due to the alternator not being able to provide the necessary energy needed to power your vehicle.
The consequent loss in power could stem from an inability of the battery to start the engine or have other electrical components function properly.
Furthermore, the drop in voltage might appear when your vehicle is running, and you will experience a more noticeable drop in performance compared to when everything is functioning correctly.

Wrap Up

An alternator helps convert mechanical energy into electrical energy and power various electrical accessories in your car.

But defects in the alternator can fail to supply power to the crank position sensor or sparkplug, resulting in misfiring.

Other reasons for misfiring include damaged fuel filters, worn-out sparkplugs, or ignition coil packs.

We recommend you take your vehicle to the mechanic to investigate the actual reason behind the misfiring.

Thank you for reading this article!

Photo of author

Sean Mendez

Hi, I am Sean, a self-confessed petrolhead. I live in Boise, Idaho with a busy family of four and our energetic Labrador retriever. Thank you for visiting my website. You can find my email on the contact page.

Leave a Comment