Hi the revolution in injection systems started in the late seventies with the Bosch Motronic multi point injection system which must have been like the second coming for the motor industry, it spawned the likes of the Golf GTI which was the benchmark every manufacturer had to better, the early systems were expensive which is why Fords first ventures in to the arena were cars like the Fiesta Si which was basically a FOMOCO carb body with a Bosch single point injector mounted above the throttle butterfly and it was so successful in giving more power and reducing emissions they then got the hots for it and started buying loads of Bosch systems tailored to their requirements I.E. XR2i XR4i Capri 2.8i Granada 2.8i, the problem was all systems on these cars still used a plenum chamber so when CARB in California started putting the thumb screws on Ford/GM for even less emissions they started developing direct injection engines as allied to the new engine management systems gave a lot more power for even less emissions and fuel, the next revolution was again developed by Bosch was Piezo injectors, these operate on a fixed height stack of Piezo slices which when electrically charged compress and lift the injection pintle to 00.04 which is the optimal height for fuel passage then further enhanced it by giving the injector multiple injection ports which enable a good spread of atomisation, only problem is the ports are about two microns and when you consider a human hair is six microns is pretty small, then the fuel companies had to step up and remove the magnesium sulphates from fuel as this solidifies in the injectors and blocks the ports and the shame of it is magnesium is an excellent upper cylinder lubricant, any engine built 2000 on requires free flowing oxygen to allow for precise metering of fuel but only within the limits set by the management system, to much it gives problem to little its the same outcome, its all about the emissions.
Steve.