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 Supply
Fuel supply is provided by chassis mounted or in-tank electric fuel pump. Some models also use 1 in-tank low pressure pump and 1 externally mounted high pressure pump. Pump delivers fuel from fuel tank through 20-micron fuel filter to fuel charging manifold assembly.
Fuel charging manifold assembly incorporates electrically actuated fuel injectors directly above each intake ports. Injectors spray metered quantity of fuel into intake air. Constant fuel pressure drop is maintained across injector nozzles by pressure regulator.
Fuel pressure regulator is connected in series with fuel injectors and is positioned downstream from them. Excess fuel supplied by pump, but not needed by engine, passes through regulator and returns to fuel tank through fuel return line.
On 1.9L and 2.3L Turbo engines, all injectors are energized simultaneously, once every crankshaft revolution. On 3.0L engine, injectors are energized in 2 groups of 3 with each group of 3 being energized every other crankshaft revolution. On 5.0L engine with SEFI, all injectors are energized once every crankshaft revolution. Each injector is energized in same sequence as ignition firing order.
ECA determines required fuel flow rate necessary to maintain prescribed air/fuel ratio for given engine operation by measuring quantity of air entering engine. Computer determines needed injector pulse width (period of time that injectors are energized) and outputs command to injector to meter exact quantity of fuel.
Mass airflow system measures intake air quantity and quality with vane airflow meter and its integral air temperature sensor. Speed/density control system uses Throttle Position Sensor (TPS), Throttle Angle Rate (TAR) sensor, Manifold Absolute Pressure (MAP) sensor and Air Charge Temperature (ACT) sensor to determine intake air quantity and quality.
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.
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