Fundamentally, the engine ECU controls the injection of the fuel and, in petrol engines, the timing of the spark to ignite it. It determines the position of the engine's internals using a Crankshaft Position Sensor so that the injectors and ignition system are activated at precisely the correct time.
The fuel injection rate is controlled by an ECU, which calculates the amount of fuel to be injected based on the signals from the sensor that detects the amount of air intake and controls the length of time to keep the fuel injection valves (injectors) open.
The ECU is the engine control unit that runs your combustion system. If there is a problem with your ECU, it may not be able to tell the fuel injectors how to property mix and deliver the air and fuel to the combustion chambers. Therefore, you may get bad performance even if the fuel injectors are fully intact.
Electronic Control Unit (ECU)
The ECU is the brain of the operation. It uses engine RPM and signals from different sensors to meter the fuel. It does this by telling the fuel injectors when and how long to fire. The ECU often controls other functions like the fuel pump and ignition timing.
Most modern internal combustion engines deliver fuel to the cylinders through some type of electronic fuel injection system. It's the ECM's job to ensure the right amount of fuel is being injected. It does so by collecting and processing readings from various sensors.
A governor is a system that is used to maintain the mean speed of an engine, within certain limits, under fluctuating load conditions. It does this by regulating and controlling the amount of fuel supplied to the engine.
They are powered by a 12 V supply either from the fuel injection relay or the ECM. In short, injectors are solenoid operated valves that use Pulse Width Modulated (PWM) signals from the Engine Control Unit to open or close a valve that permits or blocks fuel flow to the engine.
The ECU (engine control unit) uses sensors to work out the right time to fire the injectors and spray fuel into the combustion chamber. When the ECU activates the injector, pressurised fuel is sprayed into the combustion chamber through the nozzles.
Quite simply the crankshaft sensor and camshaft sensor tells the computer the position of the valves and the pistons in relationship with one another. Then the computer or ecm sends a signal to spray the fuel and fire the spark plug at just the right time for maximum power and fuel efficiency.
An injection pump is often driven indirectly from the crankshaft by chains, gears or a timing belt that also moves the camshaft. The timing of the pump determines when it will inject fuel into the cylinder as the piston reaches the BTDC point.
Common causes of injector failure
While many things can cause breakdowns, the most likely cause of premature failure is fuel contamination. Fuel contamination occurs when debris in the fuel gets past the filtration, destroying the sealing surfaces.
There are many reasons for faulty fuel injectors but the three most common issues are clogging in your car's fuel injectors, leaky and dirty injectors. You should remove the fuel injectors and clean them up before putting them back in for your car to function optimally.
The ECU then sends a command to the fuel pressure regulator via a duty cycle to achieve the desired pressure. The fuel pressure sensor is a three-wire device with battery voltage on one wire, earth on another and the third wire is the signal wire.
The Fuel Pump function is used where the ECU will be controlling an electric Fuel Pump. ECU control is preferred for safety reasons to ensure that the fuel pump is turned off in case of an accident.
ECM stands for Engine Control Module, and ECU is short for Engine Control Unit. These two acronyms represent the same component and are used interchangeably.
If it does not spray, the problem is the injector or no fuel pressure. The injector should have around 1.3 ohms of resistance, if it is open or zero resistance, it is bad. The injector could be totally clogged as well. Fuel pressure should be 9 to 13 psi.
Fuel injectors typically fail due to a buildup of contaminants such as carbon. Carbon build-up can cause a clogged or partially clogged injector, preventing the injector from closing all the way. This results in a drip that creates a misfire.
Generally, new injectors need to be programmed or calibrated to ensure they work properly with the vehicle's engine management system. Additionally, some vehicles may have specific programming requirements for new injectors, such as updating ECU software or performing an injector coding procedure.
Experts blame the excess alcohol and additives in most gasoline products because they cause premature failure of fuel injectors. It pays to know your fuel and stick with it. Other than only getting high-grade gasoline, you must also change out the oil frequently and replace bad fuel filters.
The quantity of fuel that reaches the injector is precisely controlled by an ECU which considers air temperature, throttle position, engine speed, engine torque and exhaust data gathered from sensors in and around the engine to regulate the supply at each intake stroke.
At engine start and for preheating the fuel when temperatures are low, the rail pressure is controlled by the PCV. To heat up the fuel quickly, the high-pressure pump delivers and compresses more fuel than is needed and the excess fuel is discharged by the PCV into the fuel return.