What Causes Fuel Injector Pulses to be Absent?

To start and run correctly, all engines require three things: spark, fuel and compression. If one of these three factors is defective, your engine will never run smoothly. If your engine won't start, check the security system, fuel level, spark plugs status, cylinder compression is good enough to compress the fuel, crankshaft angle, and finally injector pulse.

If you are not mechanical minded, then we suggest you search online for car repairs near me garage and let a trained technician diagnose and repair the issue

It's vital to grasp the basics of the fuel injector before diving into today's topic, which is what causes no injector pulse. So, let's get started.

History of Fuel Injection

The idea of electronic fuel injection systems was developed to solve the problems of old mechanical injection systems by relying on the reading of a different sensor feed into a control unit analyse this data and return the exact amount of fuel needed to meet better engine performance and at the same time best fuel consumption. These modern EFI systems typically consist of some basic components such as fuel pump, fuel rail and fuel injector.

What exactly is a fuel injector?

In a simple image, an injector is an electronically controlled valve that receives pressurised fuel from the fuel pump at a specific pressure level. The injector may be electromagnetically opened and closed at a very fast speed, which is controlled by the electronic control unit.

When the injector receives a signal from the control unit to open, an electromagnet moves a plunger, allowing the pressurised fuel to come out in a picture of very fine droplets, and this happens when the fuel passes through a highly engineered nozzle that atomizes the fuel to make it easy to burn, with the amount of fuel determined by the amount of time the fuel is exposed to the flame (Pulse Width). You can find out more information here. What Are Fuel Injection Systems and How Do They Work? If you are still unsure, look for repair garage near me and speak to a trained technician.

Variation in electronic fuel injection systems

SPI (single point injection) is the earliest setting that has a single injector on the throttle body regardless of how many cylinders in the engine there is always one port for fuel feeding this setting was used in the transition period from carburettors to EFI systems, but it has many drawbacks such as uneven shape and bad distribution (Multipoint Injection).

The difference in this system is that each cylinder has its own injector, which is placed as close to the intake valve as possible. This allows the ECU to give the desired air/fuel ratio to any of the possible cylinders, as well as a uniform distribution of fuel on each cylinder. The most modern setting of the injectors is GDI (Gasoline Direct Injection).

What is the reason for the lack of a fuel injector pulse?

When the fuel is sprayed and mixes with the air inside the intake manifold, the air/fuel mixture vaporises due to low pressure in the intake manifold, which is where the fuel injection ECU sensor works and sends a signal to the ECU to provide the proper air/fuel mixture ratio, the volume of fuel to be drawn from the fuel pump is determined by the volume of air taken by the engine and engine speed. All of this information is sent to the ECU, which calculates the quantity of gasoline that needs to be injected to keep the vehicle operating smoothly.

The crankshaft position sensor and camshaft position sensor are the most important signals that determine the accuracy of a signal coming out of an ECU to injectors, so to test a bad injector, check the voltage on the injector when the ignition key is turned on: NO VOLTAGE? so what causes no power to fuel injectors?

A blown fuel injector fuse

A faulty fuel injector power relay

Bad wiring harness

In this situation, you must examine and troubleshoot the source of the problem or do an internet search for car garages near me to allow a technician to diagnose and fix the vehicle. The injector fuse is generally found in the engine compartment's relay box; fuses are used to safeguard all electrical circuits and components while delivering power to them; fuses prevent short circuits in the fuel pump, fuel injectors, and electronic circuits. When these fuses break, the system they support goes out of commission, and the engine shuts down. As a result, while cranking, there is no injector pulse.

To examine a blown fuse, remove it from its socket and inspect the internal wire for continuity. If you find it cut, replace it with a new one of the same value. Likewise, try swapping the relay with another of the same value.

If you get the same result after doing all of this, it's time to check the injectors themselves. If there is no injector pulse on one cylinder, try unplugging injectors one at a time and see if the engine starts. If the engine starts when a particular injector is unplugged, it's the defective one that needs to be replaced.

Another approach to test the injector is to measure the resistance between the two terminals of each injector and compare it to the maximum and lowest values indicated in the injector datasheet; if the result is beyond the permitted bounds, replace the injector.

If you get the same result after doing all of this, it's time to check the injectors themselves. If there is no injector pulse on one cylinder, try unplugging injectors one at a time and see if the engine starts. If the engine starts when a particular injector is unplugged, it's the defective one that needs to be replaced.

Another approach to test the injector is to measure the resistance between the two terminals of each injector and compare it to the maximum and lowest values indicated in the injector datasheet; if the result is beyond the permitted bounds, replace the injector.

In this situation, there is no injector pulse or spark, which implies that your ECU has failed to operate, and you will need to replace it or see an expert.