Figure 14.8. Elements of the air supply system of the RVT system: 1 – expansion chamber; 2 – damper; 3 – throttle assembly; 4 – throttle position sensor; 5 – electromagnetic valve for heating the engine in idle mode; 6 – electromagnetic valves (for air conditioning); 7 – engine inlet air temperature sensor; 8 – air flow meter; 9 – air valve
Figure 14.9. Elements of the fuel supply system of the RVT system: 1 – fuel pump; 2 – pressure regulator; 3 – fuel filter; 4 – fuel distribution line; 5 – injectors; 6 – pressure regulator; 7 – fuel tank
The RVT system is essentially a Bosch L-Jetronic fuel injection system. The main components of this system are shown in the figure 14.8 and 14.9.
Air flow meter
The air flow meter measures the amount of air entering the engine and, using a potentiometer, converts it into an electrical signal sent to the control unit.
The air flow meter is equipped with a temperature sensor for the air entering the engine, an idle bypass system and a fuel pump switch.
Checking the air flow meter
Remove the pressure plate mounting bolts and remove the rubber boot from the air flow meter connector.
Turn on the ignition and use a voltmeter to measure the voltage between each connector contact and the vehicle ground. The "FC" and "VB" contacts should show battery voltage, the "VC" contact should show 6–10 V, and the "VS" contact should show 0.7–2.7 V.
If the measured voltages differ, check the condition of the wires and the fuse.
Release the clamps and disconnect the connector from the air flow meter.
Figure 14.10. Air flow meter connector contacts for the RVT system
Using an ohmmeter connected between the "E2" and "VS" contacts of the connector, check the resistance, which should be more than 20 ohms (figure 14.10). The resistance between contacts "E2" and "VC" should be 100-300 Ohm, between contacts "E2" and "VB" - 200-400 Ohm and between contacts "E1" and "FC" it should be equal to infinity.
Figure 14.11. Using a hair dryer to heat the inside of the air filter
Data provided by the website www.MAZbook.ru
The resistance between contacts "E2" and "TNA" depends on the air temperature in the air filter. Remove the air filter cover and using a thermometer and heat source (for example, a hair dryer) measure the resistance and compare it with the technical data (figure 14.11).
Open the air flow meter's internal plate and measure the resistance between contacts "E2" and "VS"; it should be less than 400 ohms. Between contacts "E1" and "FC," the resistance should be zero.
Make sure the inner plate moves freely and, if necessary, use compressed air to remove any deposits or particles that may be restricting the plate's movement.
Replace the air filter cover and connect the connector.
Removal and installation the air flow meter
Remove the pressure plate mounting bolts and disconnect the connector from the air flow meter.
Loosen the clamps and disconnect the main air hose and the two air supply hoses.
Disconnect the vacuum hoses going to the power steering or the A/C solenoids.
Remove the air cleaner cover, then unscrew the air flow meter mounting bolts and remove the rubber seal.
Installation is carried out in the reverse order of removal. Install a new rubber seal and upon completion of installation, check and adjust the engine idle speed.