Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1989 Geo Tracker LSi, StandardFACTORY OEM SERVICE PROCEDURE
System Performance Test 5 (TPS Wide Open Throttle Spectrum)
- 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.
- 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.
- 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.
- 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.
- 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.
Factory Service Tools
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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.