Distributor Advance Unit: Testing and Inspection

Advance Diaphragm Inspection
1. Remove the distributor cap and vacuum hoses (# 12, # 15 for Fuel-Injected Engine or # 2, # 25 for Carbureted Engine) from the advance diaphragm.
2. Connect a vacuum pump/gauge to advance diaphragm A (inside port).
3. When vacuum (more than 500 mHg, 20 in. Hg is applied to the diaphragm, the stator should turn counterclockwise and stay.
If the stator does not turn or stay, replace the diaphragm.
When vacuum is released, the stator should return.
If the stator does not return, repair or replace as necessary.
4. Repeat step 1 - 3 for advance diaphragm B (outside port.)