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.
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HOMESERVICE MANUALSJEEP1987WRANGLER BASE, 4.2 C, AUTOMATICREPAIR AND DIAGNOSISENGINE PERFORMANCESYSTEM4.2L FEEDBACK CARBURETOR TESTING
1987 Jeep Wrangler Base, 4.2 C, Automatic
4.2L Feedback Carburetor Testing
1987 Jeep Wrangler Base, 4.2 C, AutomaticSECTION 4.2L Feedback Carburetor Testing
- Description
- Diagnosis & Testing
- System Test Charts
- Test Charts Menu
- MCU Harness & MCU Connector Pin Identification
- Test No. 1 - Operational Test
- Test No. 2 - Initialization Test
- Test No. 3 - Open Loop Switch Test
- Test No. 4 - Closed Loop Operational Test
- Test No. 5 - Electronic Ignition Retard Test
- Test No. 6 - Oxygen Sensor & Closed Loop Test
- Test No. 7 - "Downstream" Solenoid Test
- Test No. 8 - "Upstream" Solenoid Test
- Test No. 9 - Idle Speed Control System Test
- Test No. 10 - Sole-Vac Vacuum Switching Test
- Test No. 11 - Sole-Vac Idle Speed Relay Test
- Test No. 12 - Basic Engine Test
- Removal & Installation
- Wiring Diagrams
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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.