[About Petrol Injectors]
Fuel Injector Valve
Symptoms of Injector Problems
[+] Lack of Power:
the vehicle has lost its performance.
[+] Poor Fuel Economy
the vehicle uses excessive fuel.
the vehicle fails the local emission test.
[+] Hard Starting
the car is difficult to start hot or cold.
[+] Rough Idle
the car does not idle smoothly.
[+] Poor Driveability
the vehicle suffers with flat spots, hesitation and "pinks".
[+] Malfunction Indicator Light
air fuel ratio error code on E0BD2.
Every year there are increasing demands being made globally on vehicle manufacturers to:
- Reduce exhaust pollution,
- Improve fuel economy,
- Increase engine performance and
- Reduce service and repair costs.
Consequently, the modern electronic petrol injection system is being fitted as standard on all new petrol engine vehicles produced worldwide
A crucial component within this system is the fuel injector valve - an electronically controlled mechanical valve that has to perform such a precise function. This valve is manufactured to a tolerance of 1 micron, possibly the finest tolerances of any mechanical part on the car. This valve operates on opening times of between 1 and 18 milliseconds. The fuel inlet port is protected by a fine 20 micron filter screen and, when the valve is opened by an electronic pulse, a precise amount of pressurized fuel is forced through small metering hole or holes.
The whole injection system is reliant upon the reliability, accuracy and performance of fuel injector valves, how often are they tested or serviced?
The inside dirt: What happens to injectors?
Problems start to occur when deposits, created by chemical contaminates in petrol as well as the petrol itself, start to build up on the surfaces of the injector - such as the filter screen, the pintle valve and guide, the pintle head and the valve seat. Heat from the engine will also dry the petrol inside the injector, leaving a tough, hardened residue. These contaminates bake onto the injectors parts. Such build ups can dramatically change the performance and characteristic of the injector and in turn affect the performance of the car's engine.
Petrol Injector Valves are manufactured to a tolerance of 1 micron. Tests have shown that a build up inside the injector of only 5 micron can reduce the flow rate through the injector by up to 25%.
Contamination in the injector or on the pintle valve cannot only affect the flow rate, it can have a dramatic effect on the Fuel Droplet Formation within the spray pattern. Increasing the size of the fuel droplet will reduce the combustible content of the atomized fuel, causing excessive exhaust pollution, poor fuel consumption and impaired engine performance. The Injector's performance is critical to the correct running of the computerized fuel injected machine. If the Air/Fuel ratio should deviate by only 1% from it preyer limits, it could have an adverse effect upon the systems ability to control and eliminate excess pollution. This would also affect the longies performance and life expectancy of emission control components like the Lambda / Oxygen Sensor and catalyst Exhaust, not to mention the money lost on wasted fuel.
Diagnosing injector performance.
Today's vehicles are fitted with self-diagnosing electronics that quickly and accurately pin point a faulty electronic engine component, even while the car is being driven.
The injectors however are part electrical and part mechanical. As we have seen, it is the mechanical aspect of the injector that is crucial to the engine's efficiency and it is easily affected by contamination.
The mechanical performance of injectors cannot be accurately analysed, checked or tested while they are still in the car. Injectors must be removed from the engine and carefully analysed for leaks, spray pattern formation and atomization and fuel delivery volumes, in a comprehensive diagnostics simulation programme. All too often injectors are overlooked during the common engine diagnostics tests, workshops see the problem, but very often find the cause of the problem.