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.
1990 Geo Tracker L4-1590cc 1.6LFACTORY OEM SERVICE PROCEDURE
Ignition Timing: Adjustments
Ignition Timing Mark And Notch:
NOTE: Start and run the engine until normal operating temperature and an idle of 800 rpm has been attained. Turn all electrical accessories "OFF," as additional vehicle systems may cause the engine idle up system to operate, and the engine idle speed will be higher than specified.
1. Connect the pick-up lead of a timing light to the number one spark plug. Use a jumper lead between the spark plug wire and the spark plug or use an inductive type pick-up. DO NOT pierce the spark plug wire or attempt to insert a probe between the spark plug wire and the wire boot.
2. Connect the timing light power leads according to the manufacturer's instructions.
3. With engine idling at 800 rpm, direct the timing light to the crankshaft pulley. If the 8° BTDC timing mark on the timing tab is aligned to the timing notch on the crankshaft pulley, the ignition is properly timed.
4. If the ignition timing is out of adjustment, loosen the distributor flange bolt and turn the distributor:
^ Clockwise to retard timing.
^ Counterclockwise to advance timing.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
