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
Throttle Position (TP) Sensor Adjust
Applying Vacuum To Throttle Opener:
1. Disconnect the negative battery cable and the TPS connector.
2. Disconnect the throttle opener vacuum at VSV and apply 16-20 in. Hg to the throttle opener.
3. Loosen the idle speed adjusting screw until it is just making contact with the throttle valve lever.
NOTE: The throttle valve must be closed.
Inserting Thickness Gauge:
4. Insert one of the following feeler gauges between the throttle lever and the idle adjusting screw.
^ Manual Transaxle - 2.2 mm (0.086 in.)
^ Automatic Transaxle - 2.4 mm (0.094 in.)
Adjusting Installation Angle Of TPS:
5. With a DVOM (digital volt ohm meter) connected between terminals C and D of the TPS connector, rotate the TPS fully clockwise. Then gradually rotate the TPS counterclockwise until the DVOM reads continuity.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.