How To Check Fuel Pump Pressure Correctly?

Jul, 2017
How To Check Fuel Pump Pressure Correctly

The consumption of four-wheelers and some heavy-duty vehicles has slowly gone up. It has become a part of our daily life, so just like the other appliances, we do have certain concerns about our vehicles. In those criteria, we must obviously check the fuel pump pressure in our vehicle.

Diagnosing the engine pressure in your car plays a major role in the engine performance. In case you are facing a low fuel pressure, it leads you to all kinds of engine recital troubles such as a low power, hard start, a very bad mileage, and poor emission.

How To Check Fuel Pump Pressure Correctly?

Thus, checking the fuel pressure pump can give a good engine performance to your car. Not all the car owners are mechanic. Obviously, we need some assistance or a type of instructor, to perform the fuel pump pressure test.

I am going to share you some of the methods I came to know on testing the pressure of the fuel pump. First I found it difficult to progress, but later it became easy for me. It gave a good diagnose over my car. Hence, my car’s performance hiked than creating problems. So, let us get started on how to check the fuel pump pressure.

How to Check the Fuel Pump Pressure Correctly?

check fuel pump pressure

Photo Credit: http://www.aa1car.com/library/fuel_pump.htm

I checked the fuel pump pressure in my car, with the following steps.

The first step I took is that I searched for the vacuum line that gets connected to the fuel pressure controller and eliminated it. The important note is that the vacuum line should be free from fuel in case any fuel is seen, then I am very sure that the regulator has failed.

If you have finished the inspection of fuel pressure regulator, then after that reconnect the vacuum line back to its original position and then, try to spot and eject the protective cap that allows the attachment of fuel pressure gauge hose.

Then next step that you should follow is, to take the fuel pressure testing apparatus from its packing case. It is not that we have to use a particular apparatus, all kinds of clip-on fuel pressure apparatus will work.

Once when you finished on fitting the fuel pressure gauge with the suitable adapter, fix the gauge line directly to the fuel examination port. If you cannot find any of the test port, then, you obviously need a fuel adapter. It should be connected to the fuel filter.

check fuel pump pressure

Photo Credit: https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

When the process of connecting the fuel pressure gauge gets over, try to turn on the key of ignition to the ON location. As soon as you have turned ON the ignition, the pressure gauge should jump immediately between 45 psi to 58 psi. Most of the Direct Port Inject (DPI) systems, the TBI which is, Throttle Body Injection is between 13 psi to 17 psi.

It shows that the pump is working sideways with the system of the electrical portion. If you cannot find any fuel pressure, then you have to check the fuel pump, fuse, and relay in the Power Distribution Center.

After trying all these steps, still, you observe no fuel pump operation admission with the power feed wire of the fuel pump, there are some few numbers of ways to do this. To energize the fuel pump, a wiring scheme helps us to distinguish the color of the wire. To spot out the exact color of the wires, the best way to know about it is the service manual.

The moment you have distinguished the color of the wire that we need to test, it should be placed in the wiring harness closer to the fuel tank where the pump is situated. The testing light should be grounded and impale the wire’s exterior coating with the examination light point.

While testing, if the light turns on with its brightness and you can find no pressure, then the fuel pump gets collapsed. If you can observe that the test bulb doesn’t illuminate, then there is a problem in the pump control relay, or there is a shortage in the wiring circuit.

The pressure of the fuel should go down between 5 psi and 52 psi. Meanwhile, the engine is running. If you have any doubt regarding the working of the pressure regulator, just give a try on snapping the throttle. As soon as you snap the throttle, you can observe a hike of pressure to 5 psi. It indicates that the pressure regulator is working properly.

If no actions deliver from the pressure regulator, check the pressure line. If the pressure line seems okay, then the pressure regulator is not working properly. When there is an underload in the engine, the fuel system cannot deliver its full working capacity. It leads the psi to drop down slightly. Ultimately the pressure should stay at 52 psi.

check fuel pump pressure

Photo Credit: https://www.youtube.com/watch?v=_oXLUqE4Sf0

In case you can find a very low pressure even there is an under load, then obviously the fuel pump has failed, or there would be a clogged in the fuel filter. Once your testing gets over, you must place a towel at the base of examination port. It will be used to collect the overloading fuel from the gauge hose.

While utilizing the towel, just loosen the pressure hose. There will be a slight leakage of the fuel. Once you have removed the hose, there will be a no stop leakage of the fuel. Now, collect the fuel in the towel that you have placed at the base of test port.

Place the fitting dust cap back to its original position. By using the towel try to clean the fuel area to make the place free from fuel. Finally, inspect the all the areas for any fuel leaks. If you come across any fuel leaks, rectify those leaks and also clean fuel injectors.

Conclusion

Maintaining a car is more important than buying it. Take a proper concern over your car for a long life and better workload. Use the best fuel additive for cleaning fuel injectors so that in can decrease the carbon in the valves.