The ECU (engine control unit) uses sensors to work out the right time to fire the injectors and spray fuel into the combustion chamber.
The throttle position sensor (TPS) is usually connected to the throttle plate shaft in the throttle body. The TPS reads the angle of the throttle valve and transmits an electrical signal to the PCM. The PCM uses this real-time signal to help calculate or modify fuel injector pulse width, controlling air/fuel mixture.
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.
The injector control pressure sensor detects the pressure of the fuel feeding the injectors, and sends that signal to the computer so that it can make the adjustments for optimum performance and 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.
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.
As the engine is cranked, the crankshaft position sensor indicates to the PCM that the engine has reached a minimum cranking speed of about 250-300 rpm. At that point, the PCM re-activates the fuel pump.
A pipe called the fuel rail supplies pressurized fuel to all of the injectors.
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.
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.
Some possible causes for this issue may be a blown EFI (Electronic Fuel Injection) main or computer fuse, a defective ignition module, a wiring issue, or perhaps even a defective engine control unit.
Often, if an injector cannot open it is due to faulty windings arising from overheating, a short out or a break. If the fuel injector doesn't open and there doesn't appear to be an issue with the windings the fault may be due to a build-up of rust.
A crank sensor (CKP) is an electronic device used in an internal combustion engine, both petrol and diesel, to monitor the position or rotational speed of the crankshaft. This information is used by engine management systems to control the fuel injection or the ignition system timing and other engine parameters.
Typically found in fuel injected engines, the manifold absolute pressure (MAP) sensor is one of the sensors an engine control module (ECM) uses to calculate fuel injection for optimal air-fuel ratio by continuously monitoring intake manifold pressure information.
Since the IC pressure sensor is typically located on the injector pump or fuel rail, you need to remove pressure from the fuel system before removing the sensor. With some vehicles, removing the fuel pump fuse may work.
High-pressure GDI fuel pumps require enough power that they need to be mechanically driven by the engine. A high-pressure GDI fuel pump is typically driven by the camshaft.
Fuel Pressure Regulator Problems
The fuel injectors can't flow normally if they have low fuel pressure due to a bad fuel pressure regulator.
The sensor measures the manifold pressure and varies the speed of the fuel pump with the sensor input.
The “pre-cat sensor” regulates fuel supply, while the downstream sensor measures the efficiency of the catalytic converter. O2 sensors can typically be categorized as either a narrow band or wide band sensor.
Electromagnetic Solenoid Actuators.
In other injection system designs, electromagnetic solenoid valves became the most common form of means to electronically control nozzle needle motion in fuel injection systems.
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.
The injector body consists of a solenoid-actuated pintle and needle-valve assembly. The control unit sends an electrical impulse that activates the solenoid, causing the pintle to move inward off the seat and allow the fuel to flow.