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So, Fuel Pressure Regulators – Control The Exact Amount Of Pressure
All fuel-injected vehicles have regulators to maintain a regulated amount of fuel flow. Fuel injectors require a set amount of pressure at the nozzle, at all times while in operation. Consequently, fuel injectors do not operate by increasing or decreasing the opening for fuel flow. They simply open the same, but for a longer or shorter duration, as needed.
Pressure can run between 25 to 60 pounds depending on the vehicle and manufacturer. All vehicles will have the regulator on the fuel rail containing the fuel injectors. The fuel regulator uses a diaphragm and spring combination, with a vacuum source on the top side of the diaphragm. Consequently, to counteract the spring pressure when high demand dictates, that higher pressure is necessary.
The computer uses sensors to determine everything from:
- Air density
- Air temperature
- Temperature of the engine
- Load on the engine
- Position of the throttle
The computer takes this information and decides on a strategy, to get the best performance out of the engine. So, One of these strategies is, to determine how long to keep the fuel injectors on. Consequently, To maintain this fuel ratio, the pressure must be maintained within one pound. When the engine is suddenly under heavy acceleration, the vacuum drops off. Only, momentarily and then recovers, within a very short period of time.
This sudden drop in vacuum during acceleration also affects the pressure. As a result, the injectors are suddenly opened longer. The fuel pump takes a second to catch up with the pressure. So, the regulator reacts to the drop in vacuum by closing the fuel return line momentarily. Finally, This gives a momentary boost in pressure.
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