1989 Geo Tracker Base, AutomaticFACTORY OEM SERVICE PROCEDURE

System Performance Test 5 (TPS Wide Open Throttle Spectrum)

  1. Ground terminal "A" on ALDL with engine idling. Connect dwell meter (6-cyl. scale) to dwell lead at carburetor. Warm engine until dwell starts to vary.
  2. Connect jumper between ECM terminals No. 5 and 22 and note dwell. See Figure . If dwell changes to less than 20 degrees, go to step 3). If dwell does not change, check ECM connections. If connectors are okay, replace ECM.
  3. Remove jumper wire at ECM. With ignition on and engine off, check voltage from ECM terminal No. 5 to 22 while depressing accelerator pedal. If there is no voltage, go to step 4). If voltage decreased from greater than 3 volts (idle) to less than 3 volts (wide open throttle), perform SYSTEM PERFORMANCE TEST 1.
  4. If voltage is greater than 6 volts, repair short to battery voltage to ECM terminal No. 5, 7 or 22. If voltage is 2-6 volts, check TPS assembly.
  5. If voltage is less than 2 volts, in step 4). Check open wire or grounded wire to ECM terminal No. 5 or 7, if okay check TPS assembly.
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When to See a Mechanic

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

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