1991 Geo Tracker LSi, AutomaticFACTORY OEM SERVICE PROCEDURE

Chart A-5, Cranks But Won't Run (Fuel Pump Problem)

With ignition on, ECM activates fuel pump relay and operates fuel pump. Fuel pump operates when engine is running or cranking, and ECM is receiving ignition reference pulses. If no ignition reference pulses are received, ECM will turn off fuel pump within 2-3 seconds after ignition is switched on. ECM is located under left side of instrument panel, near kick panel. Fuel pump relay resistance should be 56-84 ohms.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. This verifies fuel pump operation.
  2. This checks fuel pump wiring circuit. Fuel pump relay is mounted on ECM located under left side of instrument panel, near kick panel.
  3. This ensures ECM is sending a signal to fuel pump relay for 2-3 seconds.
  4. Checks fuel pump relay signal from ECM.
Fig 1: Chart A-5, Flow Chart, Cranks But Won't Run
G91C16784Courtesy of GENERAL MOTORS CORP.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.