Scirocco L4-1781cc 1.8L SOHC (1987)
Ignition Timing: Testing and Inspection
Basic Timing
Ignition Timing
Correct ignition timing is essential if the ignition and fuel systems are to deliver top performance and maintain control of harmful exhaust emissions.
Checking and adjusting ignition timing is an important part of any fuel system adjustments such as idle speed and idle mixture.
Ignition timing also needs to be adjusted whenever the distributor has been removed or taken apart, and whenever the camshaft drive belt has been
adjusted or replaced.
Requirements:
-
Engine warm-minimum oil temperature 176°F (80°C)
-
Idle speed OK
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Tachometer and timing light connected
-
Throttle switch(es) OK
To check basic ignition timing:
1. On manual transmission cars, remove the plastic plug from the timing check hole at the top of the transaxle bellhousing.
NOTE: Remove the entire plug. The smaller hole is for a special timing indicator used by Volkswagen dealer Service technicians.
2. Start the engine and let it idle. Briefly raise the engine speed above 3000 rpm three or four times.
Fig. 4-4
NOTE: Fig. 4-4; timing mark on flywheel aligned with pointer in timing check hole (top of bellhousing). Timing mark indicates 6° before top dead
center (BTDC).
4. Check the timing. With a timing light, the timing mark or the flywheel should appear at the pointer in the timing check hole in the transaxle, as
shown in Fig. 4-4.
Ignition timing specifications:
-
checking
4° to 8° before TDC
-
CIS, CIS-E
check at idle
WARNING: Keep hands and other objects clear of the radiator cooling fan. The fan may start at any rime, even when the ignition is switched off.
CAUTION:
-
The timing indication is accurate only when the engine idle speed is within specifications.
-
Check the timing marks only when the radiator cooling fan is not running.
5. Switch the ignition off. If the ignition timing is OK, disconnect the test equipment and, on Digifant cars, reconnect the coolant temperature sensor.
If timing is outside the specified checking specification, it should be adjusted.
