The throttle valve regulator is an electro-pneumatic controller controlled by the carburetor control unit and sets the throttle position within a certain range. The range of regulation extends from the minimum idling speeds to full throttle closing, that is, until traction is cut off or the engine stops. The governor tappet is adjacent to the throttle lever and can move away from the vacuum diaphragm against the force of the return spring. The required operating pressure is set by 2 solenoid valves, one valve under vacuum and the other under atmospheric pressure. The valves are triggered by signals from the control unit and thus smoothly change the pressure in the membrane and thus the position of the pusher.
When the driver gives gas, the idle switch closes in front of the pusher and thereby gives a signal to the control unit about the throttle lever moving away from the pusher.
Disconnect the connectors, air and vacuum hose from the throttle valve controller.
Connect a vacuum tester and a vacuum pump to the vacuum hose connection on the air valve.
Connect test leads VAG 1594 to pins 1 and 2 on the throttle control and connect one wire to ground (-).
Create a vacuum of at least 400 mbar with a vacuum pump and touch the second wire to the positive (+) generator terminal until the pusher is fully retracted. Pusher length a = 55±5 mm, see drawing 22-1572.
The tappet must remain retracted for at least 1 minute, otherwise replace the throttle control.
Check distance -b- between throttle lever and throttle switch with pushrod retracted. If necessary, adjust with adjusting screw -8-, see Figure 22-1572. The distance -b- must be 0.8±0.4 mm.
Switch the test leads on the throttle control from pins 1 and 2 to pins 6 and 7 and touch the free wire to the positive (+) terminal of the generator to the full exit of the pusher. Pusher length c = 72±0.5 mm. The pusher must fully exit max, in 1 second.
Attention: If the plunger moves out more slowly or does not come out to its full length, then either the filter -arrow- of the air valve is dirty (clean or replace), or defective throttle control, replace.
Measure the resistance between the following contacts with a VAG 1526 control device or an ohmmeter:
Throttle Potentiometer Resistance Set Points: between pins 3 and 4: 0 ohm (short circuit), between pins 3 and 5: 0 ohm (short circuit).
In case of deviations from the specified values, replace the throttle valve regulator.
Press the actuating lever away from the throttle switch. Measure the throttle switch resistance. Set value 0 ohm (short circuit).
Press the actuating lever against the throttle switch. Measure the throttle switch resistance. Set value ∞ ohm (gap).
In case of deviations from the specified values, replace the throttle valve regulator.
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