How Does Fuel Pressure Impact Fuel Economy?

Fuel pressure directly relates to fuel economy because it dictates how well the engine can maintain its optimal air-fuel mixture for combustion. Most fuel-injected engines require between 30 and 60 psi of pressure to reach that exact air-fuel ratio which will support efficient combustion. If the fuel pressure falls below this threshold, then the engine is running lean-too much air and not enough fuel in the mixture. This causes an imbalance, leading to incomplete combustion, hence the power produced is affected and results in increasing the engine effort to deliver the required performance by increasing fuel consumption as much as 10-15%.
Poor fuel pump performance or a clogged fuel filter will cause disruptions in the required pressure, making the engine compensate by delivering more fuel. This decreases fuel economy. In fact, according to some studies from the National Institute for Automotive Service Excellence, a car that has erratic fuel pressure will operate with as much as 20% less efficiency than those with a healthy fuel system. This also forces the ECU to make changes that try to compensate for the lean mixture, usually giving bad throttle response and slower acceleration, further impacting overall efficiency.

Very high fuel pressure can decrease fuel economy, too. Whenever the fuel pump provides excess pressure, the air-fuel mixture becomes rich, meaning there is more fuel in the combustion process than necessary. The mixture is rich-the fuel is wasted, and the emissions are high. Fuel that does not get burned leaves through the exhaust. Running a rich mixture will result in buildup on parts such as the spark plugs and catalytic converter over time, which reduces efficiency and increases maintenance costs. Keeping fuel pressure in the optimal range eliminates these issues and enables the engine to operate accordingly, which reduces unnecessary waste of fuel.

This helps in keeping the fuel pressure constant through regular maintenance and periodic replacement of the fuel filter. This usually occurs after every 20,000 to 30,000 miles to ensure good fuel economy. Mechanics usually recommend that any decline in fuel efficiency should be tracked to give some form of early warning about fuel pressure issues, especially for those cars with mileage above 100,000. This, therefore, enables the drivers to evade the expensive effects brought about by bad fuel economy and further to lessen engine wear.

An excellent fuel pump will keep the fuel system operating within a good range of pressure that optimizes performance and economy. See for more information on maintaining your fuel pressure consistent and also other quality parts: Fuel Pump.

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