Vacuum Advance
- Install tachometer and timing light. Disconnect ignition ECU connector. Disconnect vacuum advance hose. Raise engine to 3000 RPM. Note timing advance reading. Timing advance should be 12-16 degrees.
- Connect ignition ECU connector. Ground ignition coolant temperature sensor with jumper wire. Raise engine to 3000 RPM. Note timing advance reading. Timing advance should be 6-9 degrees. Replace ignition ECU if timing advance reading is not within specification.