If you have an older vehicle model, you have probably experienced vapor lock. Newer cars come with unique fuel injection systems; therefore, the problem is not common. Read on to learn about vapor lock symptoms and how you can fix the issue.
What Is Meant by Vapor Lock in Your Car?
Vapor lock happens when fuel overheats and turns to vapor in a fuel injector, fuel line, or carburetor. When it happens, it disrupts the correct air to fuel ratio and prevents fuel from reaching the specific fuel lines, resulting in engine stops. Vapor lock is more common in older car models; however, it became more predominant in carbureted engines with the appearance of the modern fuel injection system. The problem is also common when a vehicle has been idling or turned off and then back on.
Vapor lock is less prevalent in modern engines because they use in-tank, electric fuel pumps. This technology allows the pump to operate at a low point in the tank. At the same time, it’s immersed in fuel and a lower temperature compared to the older mechanical pump located in the engine compartment. Additionally, fuel is pressurized in a modern fuel delivery system.
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Modern engines are also equipped with an electric cooling fan; hence, it is more difficult for vapor bubbles to form in the fuel lines under high operating temperatures. On the other hand, many carbureted engines use a mechanical fuel pump to pull fuel out of the tank to feed the engine. When this happens, a vacuum is created in the fuel line, making fuel more disposed to vaporization under high engine temperatures.
The fuel pump sits next to the engine, allowing engine temperatures above 37.8 C to transfer to the carburetor and fuel lines. The heat vaporizes all the non-pressurized fuel in the carburetor or the fuel lines. The vapor expands, creating bubbles that displace fuel, preventing or reducing flow, and creating a vapor lock that causes your vehicle’s engine to run lean.
What Happens When Your Car Has a Vapor Lock?
When your engine is warm, it may exhibit the following symptoms of vapor lock:
- Poor performance
- Hesitation on acceleration
- Stall and start after cooling for a few hours
- Difficulty in restarting
- Lack of power
- Experience rough idle
How Do You Fix a Vapor Lock?
Sometimes it might be challenging to know if your engine has a vapor lock; however, several clues may point to it. If you suspect that your vehicle is experiencing vapor lock, you should ask yourself the following questions:
- Does your engine use a carburetor?
- Does the engine stumble or hesitate when it warms up?
- Does the condition only happen when driving under hot conditions?
- Does the warm engine stall and doesn’t start until it cools?
There are several techniques that you can use to fix a vapor lock. Here are some of them:
Cool Down the Fuel Pump
You can cool down the system by pouring cold water on the fuel pump. Before doing this, you should ensure that the ignition system is off. Cold water will help in the faster liquefaction of the vapors. It will also eliminate vapor blockage in the lines and fuel pump.
After pouring the cold water, you should wait for some minutes before turning on the ignition. You shouldn’t pour cold water for a longer time as it may result in engine-related problems.
Turn the Engine On
You can turn the engine on as soon as the vapor liquefies. Press the accelerator gently while turning the ignition. Depressing the accelerator softly will release the correct amount of fuel to the combustion chamber.
Be careful not to press the accelerator down because it may release a lot of fuel to the chamber, which may not suit the engine. Press the throttle until the engine starts running smoothly.
The engine may produce unusual noises for a while because the fuel will clear the remaining vapors from the fuel line.
How to Reduce the Chances of Getting a Vapor Lock on Your Car
Vapor lock is common in carbureted vehicles, which have an engine-driven mechanical fuel pump. Fuel-injected vehicles can also experience vapor lock, although it’s rare. Several solutions can help prevent fuel lines from overheating and eventually solve vapor lock problems in a carbureted or sometimes a fuel-injected engine. Some of the solutions include:
- Install a carburetor heat insulator or thick composition spacer block to isolate the intake manifold heat from the carburetor.
- Ensure that the fuel filter and fuel pump are not restricted.
- Ensure that the fuel lines and pumps, including the one between the carburetor and pump, are not too close or aren’t touching hot engine components.
- Ensure the return line of your fuel system is not plugged.
- Find fuel injector wrappers, which reflect heat away.
- If your vehicle has a carbureted engine, install an in-line, low-pressure electric fuel pump next to the fuel tank.
- If you have an old cooling fan, replace it with a modern electrical cooling fan. If possible, connect the fan to the engine temperature sensor.
- Heatshield carburetor, pump, and fuel lines using insulating tubing or special metal plates.
Installing a carburetor heat insulator may be your best bet on preventing a vapor lock. However, it would help if you consulted your mechanic to suggest the best possible solution for reducing a vapor lock that is specifically designed for your vehicle.
In What Weather Does Vapor Lock Occur?
A vapor lock tends to occur in hot weather or high-altitude areas. It is likely to develop when your car is in traffic because the under-hood temperature tends to rise. A vapor lock may also occur when you stop the engine while it’s still hot and park the car for a short time. The fuel in the line close to the engine doesn’t move, and it can heat up, resulting in a vapor lock.
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Following the discussed preventive measures above can help reduce the chances of getting a vapor lock. Additionally, it is best to consult a mechanic to help you develop a practical solution for reducing a vapor lock that is tailor-made for your car.