Vacuum Advance Unit, Checking For Leakage

Vacuum advance unit, checking for leakage

Work sequence






- connect vacuum tester Sun VPT 212-1 or equivalent according to manufacturer's instructions
- run engine at approx. 2500 rpm and check that vacuum at throttle valve housing is reaching vacuum unit
If NO, vacuum connection on throttle valve housing may be blocked

- increase engine speed until vacuum tester indicates higher reading than 266 mbar (200 mm Hg)
- switch vacuum tester so it holds vacuum on side connected to vacuum unit
- turn engine OFF
- vacuum reading on tester must not drop more than 10% within 1 minute, otherwise vacuum unit or hose is defective