How a Fuel Injection System Operates

A Automotive Lift Repair Orlando fuel injection system is a sophisticated electrical circuit that utilizes multiple sensors to provide inputs to a PCM (Powertrain Control Module, often referred to as the computer). The PCM processes these sensor inputs and generates a PWM (Pulse Width Modulated) signal, which is essentially a digital on/off signal. This signal dictates the amount of fuel injected into the engine.

The PCM also receives feedback from oxygen sensors, which measure the air-fuel ratio by analyzing exhaust gases near the exhaust manifolds (refer to Lesson 5 if needed). This feedback allows the PCM to adjust the fuel trim to ensure the engine runs cleanly, efficiently, and lasts longer. This sophisticated control is a key reason why modern vehicles have extended lifespans, consume less fuel, and produce cleaner emissions.

 Fuel Filter and Air Filter

Two essential filters protect the Automotive Lift Repair Orlando fuel system and engine: the fuel filter and the air filter. The fuel system is highly sensitive to contaminants and debris, so these filters are crucial for maintaining its health.

When you refuel at a gas station, the fuel may contain impurities. To prevent these from reaching the engine, the fuel first passes through a sock filter in the fuel tank, which catches larger contaminants. The fuel then moves through the fuel filter, which blocks smaller particles. Any contaminant that bypasses the fuel filter can affect the entire fuel system. Consult your owner’s manual for the recommended mileage for fuel filter replacement.

The Automotive Lift Repair Orlando air filter shields the engine from dust and dirt that could enter through the air intake system. Dirt in the engine can cause wear and potentially lead to engine failure. Therefore, like the fuel filter, the air filter is a critical component of the engine. It is inspected during every oil change and replaced as needed. (The air filter was also covered in Lesson 2 as part of general maintenance.)

This lesson focuses on the Automotive Lift Repair Orlando engine’s electrical system, particularly its key components: the battery, alternator, and ignition system. The battery provides the vehicle’s power, while the alternator keeps the battery charged. The ignition system ensures the air-fuel mixture is ignited at the correct moment during the Otto cycle (see Lesson 5 for more on the Otto cycle).

In this context, “ignition” refers to the Automotive Lift Repair Orlando engine’s system for igniting the air-fuel mixture, not the ignition key. Before 1975, the ignition system included the ignition coil, capacitor, contact breaker, distributor, and spark plugs. The ignition coil converts low voltage into high voltage, which is then routed through the distributor and plug wires to the spark plugs. The contact breaker (or points) completes and interrupts the circuit to the ignition coil, while the capacitor absorbs voltage spikes to protect the contacts.

Modern Automotive Lift Repair Orlando vehicles use a crankshaft position sensor to send signals to the PCM (powertrain control module or computer). The PCM processes these signals and controls the ignition coils, which fire the spark plugs. Some vehicles use a single coil for two cylinders, causing both spark plugs to fire simultaneously—one of which may occur during the exhaust phase of the Otto cycle, resulting in a wasted spark.

The ignition system works in tandem with fuel injection (covered in Lesson 7) to ensure the correct Otto Cycle events occur in the cylinders. Cylinder numbering and firing order can vary based on the vehicle make and model, as well as engine size.

For instance, an 8-cylinder Automotive Lift Repair Orlando engine may have cylinders numbered 1, 3, 5, 7 on the driver’s side and 2, 4, 6, 8 on the passenger side. 

Spark Plug Gap:

The spark plug gap is crucial for creating a high-heat electric arc to ignite the air-fuel mixture correctly. When the gap is too tiny, you may not be able to generate a sufficient spark.  If it’s too wide, the voltage may be insufficient to generate a spark. Either condition can lead to ignition misfires, resulting in poor performance and increased emissions.

When a battery fails, the vehicle won’t start, and you’ll need another vehicle to jump start it. Because jump starting involves creating an electrical circuit, it’s crucial to follow these steps for safety:

2. Turn off the active vehicle.

3. Check both batteries for any sulfur odor. If you detect this smell, do not attempt to jump start the vehicle, as the battery could explode due to released hydrogen gas.

4. Connect the cables as follows:

   – Attach one end of the red cable to the positive (red) terminal of the dead battery or to the jump start location specified in the owner’s manual.

   – Connect the black cable to the negative terminal of the dead battery or to the jump start location specified in the owner’s manual.

   – Connect the other end of the red cable to the positive terminal of the working vehicle or the specified jump start location in its manual.

   – Attach the black cable to the negative terminal of the working vehicle, or to a bare metal surface on the vehicle (such as the engine block). Avoid painted surfaces to ensure proper conduction.    – In summary, the order is: dead red, dead black, live red, then live black. Don’t forget that positive is colored red and negative is colored black. 

5. Start the working vehicle and let it run for about 5 minutes.

6. Try starting the dead vehicle. If it doesn’t start, the battery may be beyond repair or there may be other issues.

To help remember the process: connect the cables in the order of “Dead Red, Fred” (dead battery first, positive cable first), and remove them in the order of “Jumped Black, Jack” (negative cable first, then positive). 

Avoid jump starting diesel vehicles as their batteries require much more power, which could damage the running vehicle. You can generally jump start a hybrid car, but if its high-power battery is dead, it won’t start. A hybrid can, however, be used to jump start a regular gasoline vehicle.