Actron Advance Timing Light CP7528 - Manual (Page 20)

MEASURING VACUUM ADVANCE
Checking the vacuum advance mechanism requires a vacuum pump with
gauge in addition to the timing light.
INDUCTIVE TIMING LIGHT
1. Leave distributor vacuum line disconnected
and plugged. Connect vacuum pump to
distributor.
2. Increase engine speed to RPM specified by
vehicle manufacturer.
3. Press and hold down button. Note advance at specified RPM.
4. Use pump to apply vacuum specified by manufacturer. Note degrees
advance with vacuum applied.
5. Subtract degrees advance without vacuum from degrees with vacuum
applied. Difference is amount of vacuum advance.
6. Remove vacuum from distributor and return engine speed to idle.
NOTES
RPM XXXX
VACUUM XXXXX
ADV. RPM XX
VACUUM XX
ADVANCE WITH VACUUM
- ADVANCE WITHOUT VACUUM
Contribution of Vacuum
19