Connect the pressure gauge hoses between the distributor and the control pressure supply line from the control pressure regulator.
Remove air pockets from gauge hoses. To do this, start the engine, set the pressure gauge cock to the position to control the flow pressure and lower the pressure gauge so that it hangs freely on the hoses.
Checking the fuel pressure in the system
Check fuel pump performance and condition air filter element.
Set lever 1 (see photo) gauge to position «open», by placing the lever in line with the fitting.
Make sure a shoe is connected to the control pressure regulator.
Start the engine and leave it to idle.
Measure the fuel pressure in the system using the pressure gauge, which for the YZ engine should be within 4.5-5.2 kg / cm2, for the DZ engine - within 4.7-5.4 kg / see2.
If the pressure is not within the specified limits, replace the fuel dispenser. You can also try to eliminate the reasons for the deviation of fuel pressure from the required one.
The reasons for insufficient fuel pressure in the system can be:
- leakage of fuel lines and their connections;
- insufficient performance of the fuel pump;
- insufficient fuel supply pressure.
The reason for the increased fuel supply pressure is a violation of the adjustment of the fuel pressure regulator or jamming of its plunger.
The fuel pressure in the system is regulated by the selection of the thickness of the shims installed on the plunger of the fuel pressure regulator.
Checking the control pressure on a cold engine
Set valve 1 of the manometer to position «closed», placing it perpendicular to the fitting.
On the YZ engine, disconnect the shoe from the pilot pressure regulator, on the DZ engine. in addition, disconnect the block from the auxiliary air supply valve.
Start the engine at idle.
Determine the control pressure on the pressure gauge as a function of the ambient temperature (see table).
Pilot pressure on a cold engine
If the pilot pressure is not within the specified limits, replace the pilot pressure regulator.
Checking the control pressure on a warm engine
Warm up the engine (oil temperature 50-70°C).
Set the pressure gauge valve to position «open».
On a YZ engine, connect a shoe to the control pressure regulator, and on a DZ engine also to the auxiliary air valve.
Start the engine at idle. In this case, the control pressure should increase to 3.4-3.8 kg / cm2 after 1.3-2.5 minutes on the YZ engine and 2.5-5.0 minutes on the DZ engine.
If the pilot pressure is not within the specified limits, replace the pilot pressure regulator.
Residual pressure test
Warm up the engine (oil temperature 50-70°C).
Stop engine.
Set the pressure gauge valve to position «open».
Start the engine and let it idle until the pressure on the gauge is 3.4-3.8 kg/cm2.
Switch off the ignition. After 10 minutes, the residual pressure in the system should be 1.8 kg/cm2.
If the pressure drops sharply, turn the pressure gauge valve to the position «closed».
Start the engine and let it idle until the gauge reads 4.5-5.2 kg/cm2 on a YZ engine or 4.7- 5.4 kg/cm2 on DZ engine.
Switch off the ignition. After 10 minutes, the pressure in the system should be in the range of 1.6-1.8 kg / cm2.
The control pressure regulator must be replaced if the pressure decreases with the pressure gauge valve open, but does not decrease with the valve closed.
Checking the fuel pressure at the time of engine shutdown
Warm up the engine (oil temperature 50-70°С).
Set the pressure gauge as above.
Set the pressure gauge valve to position «closed».
Measure the fuel pressure in the system, which should be in interval 4.5-5.2 kg/cm2 on the YZ engine and 4.7-5.4 kg/cm2 on the DZ engine.
Switch off the ignition.
Measure the fuel pressure in the system when the ignition is turned off. which should decrease to 3.0 kg/cm2.
Operating principle of the supply pressure regulator 1 - fuel supply under supply pressure; 2 - fuel withdrawal to the fuel tank; 3 - plunger of the supply pressure regulator; 4 - uncoupling valve; 5 - fuel supply under control pressure.
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