Why Does My Car Surge When the AC Is On? – Troubleshooting Tips

AvatarByCarl Frisch

When the air conditioning (AC) is running in your car, you may experience a slight surging or lurching of the engine, which can be caused by one of several different issues. This issue is often caused by a problem with the AC compressor or evaporator. The AC compressor increases pressure on the refrigerant to raise its temperature, and it requires power from the engine to do so. When this component is damaged or worn out, it can cause an increase in pressure on the engine resulting in a slight surging or lurching feeling. The evaporator also needs a constant supply of refrigerant to keep cool air flowing into the cabin, and if there is too little refrigerant due to a leak, then it can cause the same issue as well. In some cases, other components such as clogged fuel filters or faulty sensors can also contribute to this problem. To diagnose and fix this issue, you should take your car to an experienced mechanic who can pinpoint the source of the problem and replace any faulty components.

Common Reasons for Car Surging when AC is on

Car surging when AC is on can be caused by a variety of different issues. The most common causes of car surging when AC is switched on include problems with the alternator, the fuel system, the ignition system, and improper idle speed adjustment settings. In this article, we will discuss each of these issues in more detail and explain how they can cause car surging when the AC is turned on.

Issues with the Alternator

The alternator is an electrical component in your car which helps to generate power for your vehicle’s systems and accessories. When it isn’t working properly, it can cause your car to surge while the air conditioning is turned on. This can happen if the alternator isn’t providing enough power to run all of your car’s systems at once or if it has worn out parts which cause it to be inefficient. To fix this issue, you’ll need to have a qualified mechanic inspect and repair or replace your alternator as needed.

Problems with the Fuel System

If there are issues with your fuel system, such as clogged injectors or a faulty fuel pump, this can also cause your car to surge when the air conditioning is turned on. This happens because these components are responsible for providing a proper amount of fuel to your engine, so if they aren’t working correctly then your engine won’t be able to get enough fuel to maintain its correct RPMs. To fix this issue, you’ll need to have a mechanic inspect and repair or replace any faulty components in your fuel system.

Malfunction in the Ignition System

The ignition system in your car consists of several components which help generate spark in order to ignite the air/fuel mixture in the cylinders. If any of these components aren’t working properly then it can cause misfires which can lead to surging while driving with AC on. To fix this issue you’ll need to have a qualified mechanic inspect and repair any faulty components in your ignition system as needed.

Improper Idle Speed Adjustment

Finally, improper idle speed adjustment settings can also lead to surging while driving with AC on. This happens because if the idle speed isn’t set correctly then it won’t be able to provide enough power for all of your car’s systems at once and will struggle when additional strain is put onto it (such as turning on AC). To fix this issue you’ll need to have a qualified mechanic inspect and adjust your idle speed settings as needed so that there isn’t too much strain put onto your engine while driving with AC turned on.

Leaking Refrigerant

Leaking refrigerant is a common issue with air conditioning systems. It is important to identify the source of the leak as soon as possible and repair it before it causes damage to other components. If the leak goes unchecked, it can cause major problems such as corrosion of the evaporator or compressor, loss of cool air, and poor fuel economy. If the refrigerant levels are low enough, it can also affect the performance of your engine. To help prevent leaking refrigerant, it is important to have your AC system regularly inspected and serviced by a qualified technician.

Preventative Measures to Avoid Car Surging When the AC is On

Using high quality fuel and oil is one of the most important preventative measures you can take to avoid car surging when the AC is on. Low-quality fuel and oil can often lead to engine misfires or rough idle which can cause car surging when turning on the AC. It’s also important to keep up with regular maintenance checkups and tune-ups for your vehicle in order to ensure that all components are working properly and efficiently. Additionally, be sure to change your engine coolant at recommended intervals as this will help prevent overheating which can also lead to car surging when turning on the AC. Finally, make sure that you are replacing your air filters regularly in order for them to remain clean and free from dirt and debris that could affect performance.

FAQ & Answers

Q: What are common reasons for car surging when the AC is on?
A: Common reasons for car surging when the AC is on include issues with the alternator, problems with the fuel system, a malfunction in the ignition system, improper idle speed adjustments, and leaking refrigerant.

Q: What can I do to prevent this from happening?
A: To prevent your car from surging when the AC is on, it’s important to use high quality fuel and oil, have regular maintenance checkups and tune-ups, keep clean air filters, and change engine coolant at recommended intervals.

Q: What are some signs that I am having issues with my alternator?
A: Some signs that you may be having issues with your alternator include dimming headlights or interior lights while driving, strange noises coming from under the hood, an illuminated battery warning light on your dashboard or instrument panel, or a dead battery.

Q: How can I tell if there is a problem with my fuel system?
A: Signs of a problem with your fuel system may include difficulty starting your car after it has been sitting for several hours or overnight, misfires or hesitation while accelerating, your engine stalling frequently, or an illuminated check engine light.

Q: What should I do if my car is idling improperly?
A: If you suspect that your car is idling improperly due to an issue such as a malfunction in the ignition system or improper idle speed adjustment, it’s best to take it to a qualified mechanic to have them diagnose and repair the issue.

In conclusion, car surging when the AC is on can be caused by various issues. The most common causes are an overcharged air conditioning system, a failing compressor, a malfunctioning evaporator, or a low level of refrigerant in the system. If you experience car surging when your AC is on, it is important to have it checked out by a qualified auto technician as soon as possible. Ignoring this problem can cause further damage to your car and may even lead to costly repairs.

Author Profile

Carl Frisch
Carl Frisch
With more than 30 years in the bicycle industry, I have a strong background in bicycle retailing, sales, marketing and customer service. I have a passion for cycling and a dedication to excellence. As a manager, I worked diligently to increase my capabilities and responsibilities, managing up to eleven mechanics (at Palo Alto Bicycles) and later as a working partner in my own store.

As the shop owner of Spoke n’ Word Cycles in Socorro, NM, the success of the mission was my responsibility, which I pursued passionately since we opened in 2003 through the spring of 2011. I am adept at managing owned and loan inventory, preparing weekly & annual inventory statements, and managing staff. The role as managing partner also allowed me tremendous freedom. I used this personal freedom to become more deeply involved in my own advancement as a mechanic, to spearhead local trail building, and advocating for cycling both locally and regionally.

As a mechanic, I have several years doing neutral support, experience as a team mechanic, and experience supporting local rides, races, club events. I consistently strive to ensure that bicycles function flawlessly by foreseeing issues and working with the riders, soigners, coaches and other mechanics. Even with decades of experience as a shop mechanic and team mechanic, and continue to pursue greater involvement in this sport as a US Pro Mechanic, and UCI Pro Mechanic.

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