Fuel is quite important for the proper functioning of the vehicle. The fuel-air mixture ratio is key in designing an engine. So, what happens when there is no fuel pressure? It means the vehicle does not run as efficiently as it should. As such, why is there no fuel pressure, but the pump works?
No fuel pressure, but the pump works are mostly because of a faulty fuel pump. It might be working but does not generate enough pressure to keep the engine running. It could also be a clogged fuel filter, stuck fuel injectors, or a faulty pressure fuel regulator.
We find that sometimes even people replace their old fuel pumps with newer models only to find that there is still low fuel pressure. It is because of such that you may not have a properly running vehicle. This guide helps you have more insight as to why this is happening and the best way to resolve it.
We have a detailed overview of what would lead to no fuel pressure even if the pump works. Also, we share more tips on keeping the engine running efficiently.
What Would Cause No Fuel Pressure?
Experiencing no fuel pressure can be hard to understand sometimes. However, the causes below should help you know what to do to resolve the issue. Here are the common causes of no fuel pressure.
Clogged fuel filter
The fuel filter is quite important for cleaning the fuel going into the engine. This means it would trap all sorts of debris and dirt. After several years of doing this job, you end up with a fuel filter full of dirt and debris.
A clogged filter makes it hard for it to do its job. Because of a clogged fuel filter, you end up with low or no fuel pressure.
Here are more symptoms of a bad fuel filter
Faulty fuel pump
Having a faulty or bad fuel pump would be the main reason for no fuel pressure. As much as the pump works, it cannot pump enough fuel that the engine needs at that particular time. This means the engine does not get the fuel it needs to keep it running properly.
Faulty fuel pressure regulator
The fuel pressure regulator controls the fuel pressure in the vehicle’s fuel rail. You can see how it is key in ensuring the fuel pressure is not too high or too low in the fuel rails. When you have a bad fuel pressure regulator, there will be no fuel pressure even if the fuel pump runs correctly.
Fuel injectors are stuck
There is a way fuel injectors are designed to work. If the injectors are blocked or stuck open, this will lead to low fuel pressure in the fuel rail.
Blocked injectors will leave you with misfire codes in the cylinder where the engine has the misfire.
Fuel pressure sensor issues
Some vehicles have electric fuel pressure regulators controlled by fuel pressure sensors. So, if the sensor has issues, it would give your vehicle fuel pressure issues. This includes having low to no fuel pressure.
Signs Of No Fuel Pressure
The question someone new to such a problem might ask is how would you know the fuel pump has a problem or any other issue that is leading to no fuel pressure? Here are some signs that help you know there is no fuel pressure.
When you press the throttle pedal, you expect the car to accelerate. However, you are now pressing it, and nothing happens. And if it happens, there has been a lag for the engine to pick up and experience the acceleration. This often indicates that the vehicle has a problem with fuel pressure.
Starting the car is hard
Another way of knowing that there is a problem with fuel pressure is because the vehicle has difficulty starting.
Whenever you start a vehicle, you need more fuel. However, the engine will start slowly if the fuel pressure is sufficient.
It might take a couple of tries before the engine gets enough fuel pressure for a successful start. Of course, you may also experience spluttering while starting the car.
Engine keeps stalling
The engine stalling can be due to many things. However, you cannot rule out fuel pressure because insufficient fuel can stall the engine easily.
The stalling can happen while driving or when the engine is at idle. This is mostly because there are huge variations in fuel pressure, making it hard for the engine to keep up.
Here are more reasons the engine keeps stalling
You have a check engine light
One thing about modern cars is that they have sensors for almost everything. This includes having a fuel pressure sensor. This sensor can trigger a check engine light in case of fuel pressure issues.
It is common for such a problem to have the code P0190, depending on the vehicle model. Make sure to use an OBD II scanner to find out more about what could be triggering the check engine light.
When there is low fuel pressure, you may also experience misfires in the engine. This is because the air-fuel mixture ratio is affected. You would generally have a weak combustion which would generally be felt as a misfire.
The vehicle has low performance
You would generally know how your vehicle is supposed to perform. When this changes, you will feel it. As much as other things would contribute to this, low fuel pressure is also included.
Low fuel pressure will make the car’s performance drop significantly. Have the fuel pressure properly checked to be sure that is what is causing the drop in performance.
Fixes For No Fuel Pressure
We have already seen what could potentially lead to low or no fuel pressure. So, what would be the best way of fixing this issue? Here are some ideas to consider.
- Start by checking your gas tank. This is to ensure that the gas tank has the right amount of fuel. If the fuel is too low, the pump will have difficulty pumping it.
- Also, check for visible signs of gas leaks. If the tank loses fuel through leaks, have them patched on the fuel tank.
- The fuel lines are also neglected, but they can sometimes cause fuel pressure. You are advised to ensure that the fuel lines are well connected to avoid fuel leaks and loss of pressure.
- Check the electrical connection between the fuel pump and the battery. In case the connection is good, then check the battery terminals. The idea is to make sure the connections are good and not loose.
- You also have to consider the fuel pump by inspecting it to see if it is faulty. This is because some fuel pumps still work even if they have a problem. The result is that such fuel pumps do not have enough pressure. Always replace a faulty fuel pump with a new one, as the manufacturer recommends.
- The pressure regulator can also have some problems. When there is such a problem, there will be no fuel pressure reaching the engine; thus, it will have performance issues. It is best to replace the faulty pressure regulator.
How To Prevent Low Or No Fuel Pressure
One thing about no fuel pressure is that you can also prevent it. The first thing is to change the filters regularly. This includes the fuel filter and filter screen. This is because you end up with no fuel pressure when they block.
Make sure that you also use high-quality fuel from a trusted fuel supplier. This ensures that you do not end up with dirty fuel that would clog the fuel pump and make it not work as expected.
Diagnostic testing is also recommended when a check engine light comes on. The light helps you know there could be a problem. This does not mean you end up ignoring it. So, perform the diagnostic tests and replace any necessary parts to improve the fuel pump’s performance.
You should have scheduled checkups so that any potential problems with the fuel pump can be identified fast and handled to prevent potential low or no fuel pressure.
What happens if you have no fuel pressure?
No fuel pressure will leave you with many engine misfires, low throttle response, rough idle, engine stalls, and much more. It is best to establish what is causing the low or no fuel pressure so that it can be fixed and the vehicle regains its performance.
What would cause my fuel pump to not engage?
A fuel pump failure can be because of several factors. The most common would be an electrical issue. Check to see if the fuel pump relay is working properly. Also, you could be having rusted connectors, melted wiring, or connectors. Another reason is that the fuel pump itself is damaged, and it can longer engage, thus the need to have it replaced.
What are the symptoms of a clogged fuel return line?
You may notice that there is a strong fuel odor in the vehicle. This will help you know if there is a problem with the fuel return line. This is because there could be a kink that blocks the fuel flow. Also, you may notice there are engine misfires and decreased engine power.