The professional method of measuring fuel pressure requires the use of a specialized fuel pressure gauge. A large selection of fuel pressure gauges allows you to measure fuel pressure on any domestic and foreign cars, including American ones. The readings obtained in this case allow you to determine the malfunctions in the injection system. Be sure to follow the manufacturer's recommendations when checking the fuel system.
Necessary
specialized kit for measuring fuel pressure
Instructions
Step 1
Before measuring pressure, carry out elementary checks of the main systems of the car and eliminate the identified malfunctions. Visually inspect the entire fuel line for leaks and corrosion. Check all connections for tightness. Make sure there is enough fuel in the tank (do not rely on instruments). Check that there is no water or any contamination in the fuel. Check all fuses and relays in the fuel system. Check for an electrical signal to the injectors. Check the ignition system: the integrity of the wiring, the operation of the spark plugs and the distributor and other components. Also check the operation of the battery and the wires coming from it. Make sure that the vacuum pipes are intact, that there are no oil and coolant leaks, and that there are no extraneous noise when the engine is running.
Step 2
The fuel system of the vehicle has a closed structure. The pressure in the fuel system is generated by the fuel pump. As it passes through each element of the fuel system, the pressure can increase or decrease. If the measured pressure is lower than the one recommended by the car manufacturer, this may mean the following malfunctions: malfunction, kink or blockage of the fuel supply line or fuel filter; breakdown of the fuel pump; clogging of the strainer in the tank; breakdown of the fuel pressure regulator; lack of ventilation in the tank; abnormal pump, filter or pressure regulator. If the fuel pressure is too high, this may mean a breakdown of the fuel pressure regulator or its control device; non-standard fuel pressure regulator; dirty or kinked fuel return line; too high pressure in the tank.
Step 3
Carry out all measurements in stages at various points of the fuel line, in strict accordance with the manufacturer's instructions. The fuel system of the car is under pressure: electronic injection systems have a pressure of about 3 bar, mechanical injection - about 4-6 bar, mono injection - about 1-1.5 bar. Therefore, release the pressure before connecting the pressure gauge. To do this, turn off the fuel pump using an appropriate fuse or relay. If the vehicle has two pumps, turn off both. If the fuel pump fuse is also responsible for the ignition system or injectors, use the manufacturer's recommended method to relieve pressure. After relieving pressure, start the engine and let it run until it stalls. Then turn on the starter for 4-8 seconds while trying to start the engine. If there is an inert ignition switch-off system, wait at least 15 seconds before trying to start again. After all the operations performed, turn off the ignition.
Step 4
The vehicle's fuel system is now ready for measurement. Connect the fuel gauge using the supplied adapters and tips, turn on the fuel pump and take measurements. Depending on the injection system installed on the vehicle, the fuel pressure should be measured at different points. For all systems, there are characteristic pressure test points: at the injector (s), before and after the filter, in the return line, at the start nozzle, at the test connector, in front of the fuel accumulator, at the junction of the return line with the tank, after the pump. In addition to these, there are specific pressure test points. Look for the location of all points and the exact value of fuel pressure at each point in the vehicle documentation.
Step 5
After all measurements, release the pressure using the cock on the fuel gauge. Repair line and tighten all connections in accordance with factory instructions. Recheck the fuel system for fuel leaks. Replace the seals if necessary.
