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Home >> Ford >> 1986 >> Bronco 5.0 N, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> 5.0L EFI EEC IV Testing >> Circuit Test >> Test II - System Check
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Test II - System Check

  1. ISC Check. Attempt to start engine at part throttle. If engine runs only at part throttle, go to TEST X - IDLE SPEED CONTROL (BY-PASS AIR)  , step 3). If engine does not run, go to next step.
  2. MAP Check. Turn key off. Disconnect MAP sensor. Connect MAP tester between harness and MAP sensor. Connect banana plugs of tester into DVOM. Set DVOM on 20-volt scale. Turn key to "ON". Measure sensor voltage output while cranking engine. If DVOM reading does not decrease from specified range, go to TEST G - MAP/BP SENSOR  , step 13). If DVOM reading decreases from specified range, go to next step.
    MAP VOLTAGE OUTPUT

    Elevation (Ft.) Voltage Output (Volts)
    0 1.55-1.63
    1000 1.52-1.60
    2000 1.49-1.57
    3000 1.46-1.54
    4000 1.43-1.51
    5000 1.40-1.48
    6000 1.37-1.45
    7000 1.35-1.43
  3. EGR Check. Disconnect and plug vacuum hose at EGR valve. Ensure that EGR valve is closed. Attempt to start vehicle. If vehicle runs, go to TEST R - FUEL CONTROL  , step 1) for all 5.0L EFI equipped models.
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