What's a vapor lock and how to avoid it?

It wasn’t that long ago when vehicles were equipped with carburetors that easily suffered from vapor lock. Modern fuel-injected engines are not susceptible to vapor lock. How do you know what a vaporlock is and how should it affect your motor?

You should avoid vapor lock if you're still driving a carbureted vehicle. This can lead to numerous issues, including difficulty starting the car and having it drive away. 

Índice de Contenido
  1. What exactly is a vapor lock?
  2. Vapor Lock Symptoms
    1. 1. The Hard Start Engine
    2. 2. Failures
    3. 3. Poor Performance
  3. How to avoid Vapor Lock
    1. 1. Get a Heat Shield
    2. 2. An Electric Fan Installed
    3. 3. Add an electric fuel pump
    4. 4. A new fuel line can be added
    5. 5. A Longer Carburetor fuel line is recommended
  4. Repairing Vapor Locks: What is the Cost?

What exactly is a vapor lock?

When the fuel gets too hot, it vaporizes. Vaporized fuel can cause the system to become lean and prevent the right amount of gasoline from reaching the engine. Most often, vapor lock occurs in older models which have a carburetor as well as a mechanical fuel pump. 

This is why carbureted vehicles are most vulnerable. The setup is essentially the same as the one above except that it operates at lower pressure. Additionally, the pump is located away from the tank. This allows for more space to allow for the formation of vapor locks. 

For the fuel-injected engines, the pump can be found inside the tank. It runs cool as it's in fuel. The system is also pressurized so that there are less chances of vapor locks.

When perfect conditions are combined, vapour lock occurs. A vapor lock is possible when temperatures are extreme, or the engine heats up and fuel lines get too close to the exhaust. This can happen if your vehicle runs a winter fuel mix or when you drive at higher elevations. 

Vapor Lock Symptoms

1. The Hard Start Engine

Starting Car

To run properly, the engine requires fuel. To run properly, the engine needs a balanced ratio of fuel to air. Combining this with compression and spark will get your motor moving.

Vapor lock is a problem that can prevent fuel delivery from being delivered to your vehicle. It can make it difficult to get the engine started if there is not enough fuel. After the car has warmed up, you might experience more problems trying to get it started.

2. Failures


Even though the engine has started, it needs to have the correct air-to fuel ratio in order for the engine to continue running as designed. The vapor lock, however, interrupts the supply and causes the engine to run less.

Lean engines are more susceptible to misfiring due to incomplete combustion. The engine could not only run rough but also stall in poor vapor lock conditions. 

3. Poor Performance

Slow Acceleration

When the engine doesn’t get enough fuel, it’s referred to as being starved. Just as we don’t perform well without food (fuel), the car isn’t going to run correctly without its power source.

Poor acceleration and hesitation can be caused by vapour lock, regardless of how hard you press the gas pedal. The malfunctioning mechanism can also cause a decrease in fuel efficiency.

How to avoid Vapor Lock

1. Get a Heat Shield

Heat shields don’t cost a lot and can be simple to install. The heat shield is an after-market accessory that keeps heat from fuel lines and other parts.

In general, it’s the chosen method when trying to prevent vapor lock. Additionally, excess material can be used on other parts. To protect fuel lines, use heat shields wherever possible.

2. An Electric Fan Installed

You can reduce your risk by using an electric fan that is after-market. You can lower engine heat by having cooling fans run continuously. 

We know heat can cause vapor lock so any effort to lower it is helpful. The engine will continue to run if the fuel lines are kept cool. 

3. Add an electric fuel pump

A low-pressure, electric fuel pump can be installed to prevent vaporlock. When the original mechanical fuel pump gets too hot, it’s time to make some modifications to the system.

This isn’t an easy step and might require the help of a qualified technician to get the job done. It should decrease the heat in the system and prevent vapor lock.

4. A new fuel line can be added

Due to excessive heat, the fuel line can become blocked and prevent fuel from flowing into the chamber. The problem might be avoided if you install a new fuelline.

It is important to ensure that your fuel line has the best insulation. After all, changing it out with the same fuel line isn’t going to solve anything. 

A longer fuel line can be beneficial. Longer lines take longer to heat up so it is better to have a longer length. Don’t forget to insulate it as well. 

If the line doesn’t heat up, the fuel won’t vaporize and get blocked up. This will ensure that the engine runs more efficiently. 

Repairing Vapor Locks: What is the Cost?

You can usually fix a situation like vapor lock without having to call a professional. You can start by applying cold water to the fuel lines. The ignition must be turned off. It is easier to start your engine when the fuel cools down. 

It is possible to also switch the ignition key and start the car by pressing the gas pedal. However, you don’t want to push the pedal all the way to the floor, or you will send an excessive amount of fuel into the system, further making it difficult to start. 

The accelerator should be kept down until your vehicle starts running normal. You might initially feel the engine sputtering when it starts, but the engine should start to run smoothly once the vapor lock has been cleared. 

If you continue to deal with a vapor lock situation and can’t figure out how to repair it, you should consult with a professional.

¡Más Contenido!

Leave a Reply

Your email address will not be published. Required fields are marked *

Go up