Innova 3568 Owner's Manual page 11

5. Aim the timing light at the timing marks and press the Advance Increment and Advance
Decrement switches, as necessary, until the timing marks are realigned to the initial (base)
timing mark as recorded in step 3.
6. The difference between the reading obtained in step 3 {initial (base) timing} and the value
obtained in step 5 is the vehicle's vacuum advance. Compare this value with the manufacturer's
specifications for vacuum advance.
7. Repeat the test, as needed, for each amount of vacuum specified by the manufacturer's
instructions.
8. Turn off the ignition and disconnect the timing light and vacuum pump from the engine. Unplug
and reconnect the vacuum hose to the distributor's vacuum port.
Checking Vacuum/Electronic Retard and Electronic Advance
The procedures for checking vacuum/electronic retard and electronic advance vary between vehicles
and manufacturers. Refer to your vehicle's service manual for specifications and procedures.
A vacuum pump equipped with a vacuum gauge is required to check vacuum retard.
Using Your Timing Light
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