Table of contents: Pressure check ↓ Checking the idle speed control valve ↓ Adjustment of carbon monoxide (CO)… ↓
Pressure check
Measuring the control pressure in various engine operating modes allows you to check the operation of the fuel dispenser and control pressure regulator.
Disconnect the fuel supply pipe to the starting injector from the dispenser-distributor and connect the fuel pressure gauge hose instead.
Remove the fuel pump relay and connect the pump power terminals with a jumper, thereby turning on the fuel pump.
Measure the fuel supply pressure using a pressure gauge; it should be within 6.1-6.5 kg/cm².
Disconnect the pressure gauge hose and connect the fuel supply tube to the starting injector to the dispenser-distributor.
Disconnect the fuel supply pipe to the lower chambers from the dispenser-distributor and connect the pressure gauge hose instead.
With the engine cold, disconnect the coolant temperature sensor connector and connect a milliammeter between the sensor and its connector. Turn on the fuel pump as described above. Turn on the ignition.
Measure the pressure on the pressure gauge and the supply current of the coolant temperature sensor, showing how the control pressure changes depending on the engine temperature.
Disconnect the control pressure regulator connector and measure the control pressure using the pressure gauge, which should be within 0.3-0.5 kg/cm².
Connect the control pressure regulator connector and measure the control pressure using the pressure gauge, which should be within 1.2-1.5 kg/cm².
Replace the fuel pump relay.
Start the engine and increase the crankshaft speed to 2500 rpm.
Release the throttle pedal and measure the control pressure on the pressure gauge. Stop the engine.
Disconnect the coolant temperature sensor connector and connect a wire with a 2.5 kOhm resistor between the sensor connector and ground, thereby simulating a coolant temperature of 20°C.
Start the engine and press the throttle pedal several times until the engine speed reaches 2500 rpm. Monitor the pressure on the gauge, which should decrease.
Stop the engine and measure the fuel pressure in the system when the ignition is turned off. If the pressure immediately drops to 0 kg/cm², replace the fuel pump check valve.
Loosen the fuel drain line fitting into the tank. Not a single drop of fuel should leak out from underneath it.
Clamp the fuel return hose to the accumulator. If the system pressure does not change, replace the fuel accumulator.
Carefully disconnect the pressure gauge hose from the fuel dispenser to avoid injury from pressurized fuel.
Checking the idle speed control valve
Start the engine, connect a reference tachometer and take its readings.
Warm up the engine to operating temperature.
Disconnect the idle air control valve connector.
Measure the resistance between the center plug and each of the outer plugs of the regulator socket, which should be within 10-30 Ohms.
Measure the voltage between the central plug and each of the outer plugs of the regulator socket, which should be within 1-2 V.
Adjustment of carbon monoxide (CO) content in exhaust gases
Connect the gas analyzer and control tachometer according to the operating instructions.
Warm up the engine and let it idle at a crankshaft speed of 650-790 rpm.
Measure the CO content in the exhaust gases, which should be within 0.1-1.1%. If it deviates from the norm, remove the plug of the adjusting screw located between the fuel dispenser-distributor and the connecting air duct of the air flow meter. By turning the screw with a special 1 mm socket wrench, achieve the required CO content. When turning the adjusting screw clockwise, the combustible mixture is enriched and vice versa.