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Home >> GMC >> 1988 >> Forward Control 5.7 M, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Fuel Injection System - Diesel >> Testing >> Injectors >> Opening Pressure Test
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Opening Pressure Test

  1. Open tester shutoff valve 1/4 turn. Slowly depress tester lever and observe gauge. Note pressure at which needle of pressure gauge stops. Some injectors may pop while other injectors may drip (this is not a leak).
  2. Opening fuel pressure should not fall less than the lowest limit of 1500 psi (105 kg/cm2 ). Replace any injector which does not meet lowest acceptable pressure. Release tester pressure.