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.
Fuel Control
The PCM controls air/fuel ratio of engine by varying fuel injector on time. Mass air flow is calculated using speed density method using engine speed, manifold absolute pressure, and air temperature change.
Different fuel calculation strategies are used dependent on operational state of engine. During crank mode, a prime shot fuel pulse is delivered followed by fuel pulses determined by a crank time strategy. Cold engine operation is determined via an open loop strategy until O2 sensors have reached operating temperature. At this point, strategy enters a closed loop mode where fuel requirements are based upon state of O2 sensors, engine speed, MAP, throttle position, air temperature, battery voltage, and coolant temperature.
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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:
- • 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.