What is the difference between a mechanical pump engine and an electronic fuel injection engine?
2 Answers
The differences between a mechanical pump engine and an electronic fuel injection engine are as follows: Different fuel supply methods: The fuel supply system of a mechanical pump engine is mechanically controlled and not regulated by the ECU; the fuel injection system of an electronic fuel injection engine is electronically controlled, and this fuel injection system is regulated by the ECU. Different operating methods: When starting an electronic fuel injection engine (including cold starts), it is generally unnecessary to press the accelerator. This is because electronic fuel injection engines are equipped with cold start enrichment and automatic fast idle functions for cold starts, ensuring smooth engine starts whether the engine is cold or warm; a mechanical pump engine, however, requires pressing the accelerator.
As someone who has worked with engines for a long time, I've seen many differences between mechanical injection and electronic fuel injection systems. The mechanical injection engine, commonly known as the mechanical fuel injection system, relies on a high-pressure fuel pump and mechanical devices to directly control fuel injection without electronic intervention. This makes it structurally simple, low-cost, and easy to maintain. However, its fuel injection quantity and timing are often imprecise, leading to higher fuel consumption, incomplete combustion, and more black smoke emissions. In contrast, electronic fuel injection (EFI) uses an Electronic Control Unit (ECU) along with sensors to monitor and precisely adjust the injectors' operation in real-time. It optimizes injection timing based on throttle position, engine speed, and air conditions, resulting in more complete combustion, smoother power delivery, significantly lower fuel consumption, and reduced emissions. The key difference is like comparing manual human control to an intelligent automated system—mechanical injection suits those with limited budgets but diligent maintenance habits, while EFI fits the modern era's demand for fuel efficiency, performance, and environmental friendliness. Modern vehicles mostly use EFI due to stricter regulations, phasing out mechanical injection. In terms of driving experience, EFI offers smoother operation, quieter performance, and less hassle, though diagnosing faults requires professional tools. Long-term, EFI proves more cost-effective.
