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Home >> Ford >> 1990 >> Bronco II 4WD, Standard, M5OD-R1 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Air Injection Systems >> THERMACTOR Idle Vacuum (TIV) Valve
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THERMACTOR Idle Vacuum (TIV) Valve

  1. With engine at idle and transmission in Neutral, apply vacuum to small nipple and place fingers over TIV valve atmospheric vent holes. See Fig 1 . If no vacuum is sensed, TIV is damaged and must be replaced. If vacuum is sensed, go to next step.
  2. With engine at idle, apply vacuum to TIV valve large nipple using a vacuum pump. See TIV VALVE (LARGE NIPPLE) VACUUM SPECIFICATION  . If vacuum is not held, TIV is damaged and must be replaced. If no vacuum is sensed, replace valve.
Fig 1: Identifying Thermactor Idle Vacuum (TIV) Valve
G90A14332Courtesy of FORD MOTOR CO.
TIV VALVE (LARGE NIPPLE) VACUUM SPECIFICATIONS

TIV Decal Color Code Vacuum in. Hg. (kPa)
Ash 5.1-10 (1.5-3.0)
Red 11.8-15.2 (3.5-4.5)