Exhaust Oxygen

-02 Sensor

Major Inputs Affecting Fuel and Spark

These six sensor inputs account for practically 100% of the fuel and spark calculation.

Fig. 5-39


Step 1

Manifold Pressure Sensor



—> —>

Basic Injection Duration Determined





Step 2

Corrected Injection Duration Determined

(Basic Injection Duration Correction)

Intake Air Temp. Sensor

Intake Air Temperature Correction

Warm-up Enrichment

After-Start Enrichment

Power Enrichment

Air/Fuel Ratio Feedback Correction

Water Temp. Sensor

Throttle Position Sensor


Oxygen Sensor


Step 3

Final Injection Signal Determined (Voltage Correction)

Battery Voltage


Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

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