Test to Identify Performance Of Fuel Delivery System (FDS)

The fuel delivery system is an important part of your car. It plays an important role in making the engine efficient. Therefore, it’s important periodically check it and fix the issues, if any timely. Some of the performance tests to judge how well the fuel delivery system is working are as follows.

  • Fuel Pump Volume Testing
  • Fuel Pump Current Draw Test
  • Pressure Leak Down Test
  • Fuel Injector Test
  • Fuel Gauge Sending Test

We’ll discuss each in this article briefly.

Fuel pump volume testing

  • To test the performance of fuel pump, open the pressure line, run fuel pump. Take a sample of fuel in a container.
  • The pump needs to deliver a fixed amount of fuel within a fixed time interval. Compare the volume of the fuel you get according to manufacturer’s guidelines.
  • Check fuel filters – if they are damaged or clogged up, it’s a cause for under-performance of the pump. If the filters are fine you need to undergo additional check-ups
  • Initial fuel pump pressure and volume tests are usually performed in static condition. Testing of the vehicle in static condition will allow you to quickly determine if fuel pump is capable of operating and is capable of generating required pressure.

Fuel pump current draw test
A fuel pump current draw test should be performed at any time if poor performance occurs. You need to check the FDS. The fuel pump current drawn can be measured by inserting an ammeter in series with the fuel pump circuit. If the readings of the ammeter are not according to specifications, it indicated that the pump needs replacement.

Pressure leak down test

  • If you experience difficulty in starting the car when you restart your car after a prolonged shutdown, it is probably because of a leaking in the fuel supply system. We are not talking about external leaks such as joints but instead, we are talking about internal fuel leaks.
  • It’s also important to know how fuel supply system pressure is performing properly during engine operation. It is important to know what the fuel supply system is doing right after the engine is shut off.
  • Checking for an internal fuel pressure leak down problem

For engines that have fuel service port valves, an Electronic Fuel Injection (EFI) pressure Gauge is used to test fuel pressure leakage.

Fuel injector test

  • If you need to check fuel injectors to make sure that, they are working properly, here are some of the basic steps to check your fuel injectors.
  • The electronic fuel injection system relies on electronic signals that control the working of the injector.. Using a ohmmeter we can check the electrical resistance of fuel injector to make sure that the injector is working properly are need to replace. There are two types of electrical charge for fuel injectors: High Impedance and Low Impedance.
  • High Impedance injectors will range between 12 to 17 ohms whereas Low Impedance injectors will range between 2 to 5 ohms.
  • Manual fuel injector cleaning machines are used to clean the fuel injectors. Many machines used to unclog the fuel injectors to perform better.

Fuel gauge sending test

  • There are several ways to find out whether the sending unit is doing its job. One of the methods is to unplug the sending unit connector and place the ohmmeter up to the sending unit terminals.
  • Check the resistance. If it isn’t within the range of minimum and maximum measurements, you will find problem, if that is the case replace the sending unit.
  • To know how much fuel is there in the tank remove the gas cap and insert a piece of wire into the filler neck like dipstick.
  • Another method is to remove the sending unit from the tank and test the sending unit using an ohmmeter.
  • In vehicles like cars, the sending unit should read between 8 and 12 ohms reading when the float is at the full position, and 60 to 80 ohms when the float is at the empty position.
  • No change in readings would tell us the need of a new sending unit.

You can do the tests discussed here. However, it’s sensible to get them done by expert professionals.

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