Warm up the engine. The engine can be considered warm. when the lower radiator hose becomes warm. The minimum oil temperature is +60°С for a carbureted engine, +80°С for an engine with a fuel injection system.
Turn off the air conditioner.
- VEZ: The knock sensor is OK, while the engine electronics control lamp does not give any malfunction signals.
- VEZ for 83/85 kW engines: Throttle position switch (cold running contacts) included.
Caution: The idle and knock sensor contacts influence the ignition timing. If the knock sensor is not working, the ignition timing is shifted later by 10°to a later direction after each gassing.
Connect the tachometer and stroboscope in accordance with the instructions.
Attention: on the vacuum diaphragm regulator it is removed or remains connected depending on the model, see ignition timing table.
Start the engine and let it idle.
Engine NQ up to 7.88: insert a replaceable fuse into the fuel pump relay and check the ignition timing no earlier than 4 seconds later.
NG engine from 8.88: connect a control voltmeter, for example M.F.P-1527, to the diagnostic connectors -A- and -B- as shown in the figure. The diagnostic connector is located in a recess under the shelf in the footwell on the driver's side.
Connect plugs -C- and -D- and keep connected during the entire test.
Attention: Already after 4 sec. after connecting the plugs, the VEZ control unit sets a constant ignition timing for verification.
Illuminate the window in the clutch housing with a strobe light.
Attention: There is danger from rotating pulleys and V-belt.
The ignition is adjusted correctly if the ignition timing mark appears to be standing still under the pointer.
If the ignition marks do not match, loosen the distributor clamping bolt and turn it so that the marks match. To turn the distributor, you can lightly tap the handle of a screwdriver in the direction of rotation.
Tighten the bolt to 25 Nm.
NG engine up to 7.88: remove the fuse on the fuel pump relay.
NG engine from 8.88: Disconnect plugs -C- and -D-. Raise the engine speed above 2500 rpm for a short time and then let it idle. The ignition timing should now fluctuate between 7°and 20°before TDC.
Check idle setting.
Check ignition timing again.
Remove gauges.
If removed, fit the vacuum line onto the distributor or control unit.
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