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Home >> GMC >> 1983 >> Magnavan 6.2 J, 475/M40 >> Repair and Diagnosis >> Engine Performance >> System >> Pulse Air Injection System >> System Testing >> Functional Test
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Functional Test

  1. Remove air cleaner-to-plenum pipe hose from plenum pipe. Slide a length of tight-fitting 3/4" (19 mm) hose onto plenum pipe. Using an adapter, connect a hand vacuum pump to hose.
  2. Apply 17 in. Hg vacuum. Note time required for vacuum level to drop from 17 in. Hg to 6 in. Hg. If less than 2 seconds, remove check valves and test individually. Replace check valve(s) which fail leak-down test.
Fig 1: Pulse Air Injection Reactor (PAIR) System Components System functions without need of a mechanical pump.
G8883
NOTE: If system fails leak-down test, ensure that failure is not due to a leaking test hose or connection.
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