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Pickup (EFI) & Trooper II

  1. Turn ignition off. Unplug power transistor harness at connector. Power transistor is mounted on intake manifold on EFI equipped Pickups, and mounted on ignition coil on Trooper II.
  2. Disconnect high-tension secondary wire from distributor cap. Hold high-tension cable about 1/4" from engine. Turn ignition on.
  3. Connect positive side (+) of 1.5 volt dry cell battery to "Y" terminal of power transistor, and negative (-) side to ground.
  4. Disconnect dry cell battery and check for spark at secondary wires. If no spark occurs, check wiring harness. If wiring is okay, replace power transistor. See Fig 1. See POWER TRANSISTOR CIRCUIT CHECK  table.
POWER TRANSISTOR CIRCUIT CHECK

Circuit Resistance
ECM Pin Connector No. 5 & Ground Infinity (No Continuity)
ECM Pin Connector No. 10 & Ground 0 (Continuity)
Power Transistor Base-to-Intake Manifold (1) 0 (Continuity)
ECM Pin Connector No. 5-to-Terminal "L" (2) 0 (Continuity)
(1) EFI equipped Pickups.
(2) Trooper II.
Fig 1: Power Transistor Circuit
G94239Courtesy of ISUZU MOTOR CO.
NOTE: On Pickup (EFI) and Trooper II models, a faulty power transistor will set a Code 23, 25 or 54.