Vanagon F4-1970cc 2.0L (1982)
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bring notch back to original setting by turning knob on tester and read off advance value
Note: To determine centrifugal advance, subtract basic advance angle from last advance angle measured
Example last advance angle measured (-) minus basic advance angle (=) centrifugal advance
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repeat check at 3400 rpm
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reconnect vacuum hose when test completed
Vacuum Advance Unit, Checking For Leakage
Vacuum advance unit, checking for leakage
Work sequence
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connect vacuum tester Sun VPT 212-1 or equivalent according to manufacturer's instructions
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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
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increase engine speed until vacuum tester indicates higher reading than 266 mbar (200 mm Hg)
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switch vacuum tester so it holds vacuum on side connected to vacuum unit
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turn engine OFF
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vacuum reading on tester must not drop more than 10% within 1 minute, otherwise vacuum unit or hose is defective
Vacuum Advance, Checking
Vacuum advance, checking
Work sequence
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connect SIEMENS 451 tester or equivalent, or tach and timing light according to manufacturer's instructions
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connect vacuum tester between throttle valve housing and vacuum advance unit connection
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set vacuum tester to allow vacuum to pass through
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start engine and run at idle
manual: 800 - 950 rpm
automatic: 850 - 1000 rpm
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if using SIEMENS tester or equivalent, read off indicated advance angle (basic angle) and note
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if using timing light, flash scale and note advance angle (basic angle)