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, AutomaticFACTORY OEM SERVICE PROCEDURE
System Performance Test 6 (Fuel-Cut System Operational Check Spectrum)
- Warm engine until choke is fully open and A/C off. Connect tachometer. Connect voltmeter between ground and terminal "B" of fuel-cut relay See Fig 1 .
- Open throttle slightly and keep engine at 3500 RPM. Note voltage. If voltage is less than 6 volts, go to step 3). If voltage is greater than 6 volts, check for open between terminal "B" and ECM terminal No. 14. If circuit is not open, adjust idle switch. If adjustment is okay, ECM or connection is bad.
- Return throttle to idle while checking voltage. If voltage changes, go to step 4). If voltage does not change, check adjustment of idle switch and A/C fast idle diaphragm.
- If voltage rises greater than 6 volts, then falls again to low level when engine drops below 2000-2500 RPM, fuel-cut circuit and idle switch adjustment are okay. If A/C equipped, repeat test with A/C on.
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.