Required Electronic Components
With most common-rail accumulator fuel-injection systems, pressure generation and fuel injection are completely de-coupled from each other. The injection pressure is generated independently of engine speed and injected-fuel quantity. The fuel is stored under pressure in the high-pressure accumulator (the "rail"), ready for injection. The driver defines the injected-fuel quantity, and the start of injection and injection pressure are calculated by the electronic control unit (ECU). The ECU then triggers the solenoid valves so that the injector at each cylinder injects accordingly.
The ECU requires sensors for the system to function. Sensors providing data to the ECU can include a crankshaft-position sensor, a camshaft-position sensor, throttle-position sensor, boost-pressure sensor, rail-pressure sensor, coolant sensor, and mass air meter. Using the input signals from these sensors, the ECU measures the driver's requirements (accelerator-pedal setting) and defines the instantaneous operating performance of the engine and the vehicle as a whole.
The mass air meter provides the ECU with data on the instantaneous airflow in order to comply with emissions regulations. For engines equipped with turbochargers and boost-pressure control, there is also a boost-pressure sensor. Diesels respond especially well to turbocharging. At low outside temperatures and with the engine cold, the ECU applies data from the coolant-temperature sensor and the air-temperature sensor to adapt set point values for the start of injection, post injection, and parameters to the particular operating conditions. Taken together, these basic functions control the injection of diesel fuel at the right moment, in the right quantities, and with the correct injection pressure to ensure that the diesel engine runs smoothly and economically.
Glow Plugs to Improve Performance
Glow plugs, which provide the initial heat to create combustion to start a diesel engine, contribute significantly to the new, smoother diesels.
In many older diesel engines, current to the glow plugs is shut off after they have reached the minimum diesel starting temperature (15,620 degrees Fahrenheit), and the ignition is turned to the start position. Since the late 1990s, however, most diesel-engine control systems are designed to keep the glow plugs "turned on" while the engine is cranking and for a brief period after the engine begins to run. This feature, called post glow, enhances engine combustion for improved emissions and provides for a smoother idle during initial cold-weather start conditions,
The post-glow heating phase generally runs from 20 seconds up to 3 minutes, dictated by the vehicle specifications, ambient air temperature, engine temperature, and the glow plugs themselves. Bosch's Duraterm technology and glow plug construction, for instance, utilizes a self-regulating system that reduces glow wait time by more than 50 percent and allows the glow plug to stay "on" longer for more efficient diesel startup. With Duraterm technology, glow plug damage due to overvoltage and heating is virtually reduced for maximum service life.
Install the new filter. | 
The barometric-pressure sensor sometimes fails on these vehicles. It will show up as an appropriate cycle with a scan tool, and the sensor is easily replaced. Also, watch for a cracked or broken vacuum hose from the source in the intake manifold. |
Ford's popular Power Stroke diesel, in 7.3 and 6.0 versions, is an International engine. The 7.3 has all engine gears on the front of the engine, while the 6.0 has all gears in the rear. | 
The latest piezo diesel fuel injectors, such as this Bosch unit, have 75 percent fewer moving components and mass, which allows them to switch at double the speed of previous solenoid-valve and piezo injectors. |
Fuel is atomized at extreme pressure as it's introduced into the combustion chamber. | |