How To Test A Fuel Pump Without A Pressure Gauge

You are in a rush but your car refuses to start, it can be frustrating. There could be many reasons for this including a dead battery, bad spark plugs, etc. but another major cause for this problem is low fuel pressure reaching the engine from the fuel tank. You probably know that it is necessary that the fuel tank is at a specific level for the car to run correctly.

A pump that does not work properly can stop an engine from starting. You can easily test a fuel pump with a pressure gauge. What happens when there is no pressure gauge around to check the fuel pump? Check for more information over here. 

Find Out When To Check The Fuel Pressure?

Before you start checking the fuel pressure, you ought to first know if there is a need to do so or not. Understanding the functioning of the injection and the fuel tank system works. From here, the fuel goes into the combustion chamber and the magic starts.

A fuel pump is part of a fuel system and is immersed in the fuel tank. It is the fuel pump’s job to suck the fuel and run it through the filter for removing any impurities.

The fuel tank is situated on the backside of a car and from here the fuel travels to the engine in the front, so it needs the right pressure. Correct pressure is essential for the performance of the engine and affects its power.

Signs Of Low Fuel Pump Pressure

There are several signs of low fuel pressure, and once you can understand the problem you will be able to correct it at the right time. 

  • If you notice your car struggling, then you know something is wrong. When the fuel pump is weak, it will be difficult to match the demands of the engine. This problem is more obvious in certain situations such as speedy acceleration, climbing an incline, etc. when your vehicle needs all the power. 
  • If you start your car, but it does not start but only revs. A car can start properly only if the fuel pump delivers the fuel. With low pressure, the pump cannot help the fuel reach the injectors for combustion. 
  • When you notice the engine sputtering and then running normally, alternatively, especially when you are driving at high speeds, the problem could be with the fuel pressure. The pressure is not enough for a continuous stream of fuel for long periods and makes the engine stop and go. 

Things You Should Keep In Mind Before Checking The Fuel Pressure

Once you can recognize the various signs of low pressure, now it is time to check the fuel pump. In a garage, the mechanics use a pressure gauge which is specially made for this purpose. What if you want to check the fuel pump pressure but don’t have a pressure gauge? Here is how you can do it:

  • If you put your key in and turn it to the On position from the Off position, you may hear a buzzing sound. The sound is coming from the fuel pump and is a clear sign that you need to change the pump or some other part.
  • If along with the buzzing sound, you notice that the car’s engine is stalling. You must check the fuel pump that is usually located under the backseat of the car. Remove it and you will notice a plastic cap that covers the pump. Find the output port which is connected to the filter and disconnect the hose coming from the pump to the filter. Use your finger or thumb to block the passage. Now ask someone to start the car. If you feel pressure against your finger, then you have good fuel pressure. On the other hand, if you don’t feel any pressure then you should replace the pump. 
  • You may have to replace the filter if you find that the problem is not with the fuel pump.  If there are many impurities in the fuel, then the filter maybe is blocking the way for the fuel to pass and build up the right pressure. 
  • Check the fuel pipelines coming out from the fuel pump. Sometimes the pipes get twisted or develop a crack while you drive on bumpy roads. Such damages can cause the fuel pressure to drop low. 

FAQs

Q. What is considered ideal fuel pressure?

A. Each engine is designed differently and there is no ideal fuel pressure gauge. It depends on the horsepower, engine displacement, and torque that each engine is supposed to deliver. So, some vehicles may require pressure between 44 and 50 psi while some vehicles may require pressure between 40 and 80 psi. 

Q. How much pressure is required at an idle position?

A. Fuel pressure varies depending on the engine load. More fuel is consumed if there is more load on the engine. The higher consumption results in reducing the fuel pressure when the car is idle. The pressure varies from vehicle to vehicle but usually, it is about 40 psi. 

Q. How do you use a gauge to check fuel pressure?

A. by using a gauge you can get precise results. Most cars have a fuel pressure testing point, which is situated close to the fuel injectors. You need to disconnect the hose that is coming in and connect the gauge to the pipe. You can ask someone to start the car and rev up and then check the pressure gauge. Check it against the manual provided with the car. 

Final Thoughts

Fuel pressure is one of the important factors that can immediately affect the performance of your car. You must carry out periodic maintenance and take care of the complete fuel system.

Be regular in changing the oil filter and follow the manufacturer’s instructions. Measuring fuel pressure without a pressure gauge may not be accurate, especially if you are doing it for the first time. take help from professionals and learn to do it on your own accurately. 

Liam

Hi, I'm the initiator and writer of this blog. Cars were and will be my first love, and my favorite hobby, that's why I decided to start this blog and write about my discoveries and techniques to improve my cars or repair them.