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 Hyundai Excel Base, 2D Hatchback, StandardFACTORY OEM SERVICE PROCEDURE
Engine Controls - Theory & Operation
- Introduction
- Computerized Engine Controls
- Notes
- Control Unit
- Input Devices
- Notes
- Air Conditioner Switch
- Airflow Sensor
- Atmospheric (Barometric) Pressure Sensor
- Battery Voltage
- Coolant Temperature Sensor (CTS)
- Engine Speed Sensor
- EGR Temperature Sensor (California)
- Idle Switch
- Ignition Switch
- Ignition Timing Adjustment Terminal
- Intake Air Temperature Sensor
- Inhibitor Switch (Automatic Transmission Only)
- Motor Position Sensor (MPS)
- Oxygen Sensor
- Power Steering Oil Pressure Switch
- TDC Sensor & Crankshaft Angle Sensor
- Throttle Position Sensor
- Vehicle Speed Sensor
- Output Signals
- Fuel System
- Ignition System
- Emission Systems
- Self-Diagnostic System
- Miscellaneous Controls
Factory Service Tools
Use the Manual With the Right Hardware
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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.
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