LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Volkswagen >> 1985 >> Jetta GLI, Standard >> Repair and Diagnosis >> Engine Performance >> Ignition System - BOSCH Hall Effect >> Testing >> Vacuum Advance Test >> All Models (Except GLI & GTI)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

All Models (Except GLI & GTI)

  1. Connect tachometer and timing light to engine. Connect Vacuum Advance Tester (VW 1368 ) and hand-held vacuum pump to vacuum advance diaphragm. Turn on tester.
  2. Start and run engine at 800-1000 RPM. Check ignition timing and adjust if necessary. Using pump, apply vacuum until ignition timing begins to change. Record vacuum. Vacuum advance mechanism should start advancing timing at 4-5 in. Hg (100-160 mbar on tester).
  3. Increase vacuum until timing stops advancing. Vacuum advance should be 10-14° at 7-8 in. Hg (180-195 mbar). If necessary, reduce engine RPM to below 1000 RPM to obtain reading.
scientia non olet · About LEMON Manuals