THE CAR NAIRA BLOG

In a car engine, an intake manifold distributes the air flow evenly between the cylinders. In many modern cars, intake manifolds is made of plastic as a compromise between weight and cost.  Often an intake manifold holds the throttle valve (throttle body) and some other components. An intake manifold consists of the plenum and runners. In some V6, V8, V10, V12 and W12 engines, an intake manifold can be made of several separate sections or parts. An intake manifold The intake air flows through the air filter, intake boot (snorkel), then through the throttle body, into the plenum, then through the runners and into the cylinders.  Path of airflow into an engine In modern cars, the engine idle speed is also controlled by the throttle body: at idle, it opens at a very small angle. Because the throttle body is almost closed when the engine runs at idle, there is vacuum inside the intake manifold. If there is a vacuum leak somewhere in the manifold, the engine will run rough (unstable) at idl

An ignition coil is a part of the vehicle's ignition system. It converts 12V battery power into high voltage in order to create a spark at a spark plug. The spark ignites the air/fuel mixture in the engine cylinders. An ignition coil cut-out and a plug Most of the modern cars have one ignition coil per cylinder. Often, an ignition coil is installed right over the spark plug. This setup is called coil-on-plug. It is more popular in modern engines. On-plug coil In some cars, ignition coils for all cylinders are combined into one coil pack. In older cars with a distributor, a single coil is used for all cylinders. See this example of a single ignition coil in a Volkswagen air-cooled engine. A coil pack in a Volkswagen Ignition coil problems Ignition coils are common to fail in many cars. Symptoms of a bad ignition coil include engine shaking, sputtering and lack of power (misfiring). The Check Engine light will flash repeatedly or stay on solid on the dash. In cars with a single ignit

Fuses are safety devices that protect electric circuits in a car from excessive current (overloading). Without a fuse, an overloaded wire could melt or catch a fire. Each circuit has its own fuse. Several larger fuses with high Amp rating protect multiple or high-current circuits, such as electric power steering or radiator fan circuits. There is also at least one main fuse. Often the main and high-Amp fuses are installed closer to the battery.  Fuse box Modern cars have at least two fuse boxes. In most cars, one fuse box is installed under the hood; the other is located inside the car. A fuse box in the cabin of a car When any electrical component in a car doesn't work, the fist step is to check the fuse that protects the circuit with this component. You can find the fuse map in the owner's manual, or on the fuse box cover. In many cars there is a tool to pull the fuses that might be located in the fuse box or in the fuse box cover (if the local electrical technicians haven

All modern cars have disc brakes on front wheels and disc or drum brakes on the rear axle. How do disc brakes work? The main component of the disc brake setup is a brake calliper. The hydraulic piston(s) inside the calliper can apply clamping force to the brake disc using two brake pads. The clamping force can slow down or stop the rotation of the disc and the wheel. A disc brake assembly Passenger cars, SUVs and pickup trucks on the road today have a hydraulic braking system filled with brake fluid. When the driver presses the brake pedal, it pushes the piston inside the brake master cylinder that creates pressure within the hydraulic braking system. The brake fluid transfers the pressure to the brake callipers that apply brakes to the wheels.  How a disc brakes works Parts of a Disc Brake Parts of a disc brake assembly Brake Disc (rotor):  The brake disc (rotor) is mounted on the hub and rotates together with the wheel. During braking, kinetic energy of the vehicle converts into heat

Many modern cars have a battery current sensor. It might also be called a battery management or monitor sensor, or simply battery sensor. Typically, a battery sensor is installed on the negative battery terminal or on the cable. It might be installed on the positive terminal. Some cars have two sensors, one on each terminal.   A BMW battery sensor How the battery sensor works: it measures the current to and from the battery. It may also monitor the voltage, state of charge and state of health of the battery (aging). In some cars, it even measures the temperature of the battery. The vehicle computer (Body control module BCM or Powertrain control module PCM) uses these inputs to precisely adjust the charging system voltage, idle speed and other parameters for better fuel efficiency and longer battery life. This system is called Power or Battery Management System or BMS. If the system detects that the battery is getting weak, it may turn off some electrical accessories (load shedding), su

An alternator is a generator of electric power in a car and is a major component of the vehicle's charging system. All cars with an internal combustion engine except for some hybrids have an alternator. When an engine is running, the alternator charges the battery and supplies additional electric power for the vehicle electrical systems. It is bolted to the engine and is driven by a serpentine belt (drive belt). An alternator An alternator is a maintenance-free unit. It can last for up to 10-15 years without any repairs. If an alternator fails, the car may still run for a short time on battery power (older cars). However, the engine will stall as soon as the battery charge is depleted.  Symptoms of alternator problems The most common symptom of a problem with your vehicle's charging system is a battery-shaped warning light (in the photo) or the "CHARGE" icon that comes on while driving. Normally this warning light should come on when you turn the ignition, but should

Air fuel ratio sensors(early 2000's) are an evolution of conventional oxygen sensors (1980's). An air fuel ratio (A/F) sensor measures oxygen content of the exhaust in a wider range. It looks very similar to the conventional oxygen sensor, but has more wires. A Toyota corolla air fuel ratio sensor The air fuel ratio sensor is installed in the exhaust manifold or in the front exhaust pipe, before the catalytic converter. The job of the air fuel ratio sensor is to measure the oxygen content in the exhaust and provide feedback to the engine computer (PCM). Based on air fuel ratio sensor signal, the computer adjusts the air to fuel ratio to keep it at the optimum level. Difference between oxygen sensors and air fuel ratio sensors Air fuel ratio sensor problems Often a sensor gets contaminated or simply fails with age. In some cars, the heating element inside the sensor fails causing the malfunction. In some cars, a sensor wiring may get shorted out after rubbing against metal parts

With tighter fuel economy regulations in developed countries (we don't care about this in Nigeria), car makers use turbocharged engines in more and more cars. With a turbocharger, the vehicle can have a smaller engine and use less fuel when coasting, idling or in stop-and-go traffic. When needed, a turbocharger kicks in and provides extra power. A turbocharged Audi engine What does a turbocharger do in a car? A turbocharger A turbocharger is a power-boosting device attached to the vehicle exhaust manifold. A turbocharger has two separate ports, exhaust and intake. A turbocharger shaft has small turbines installed on both ends. One turbine is in the exhaust port (pink in the photo), another is in the intake port (blue in the photo). Hot exhaust gases rapidly exiting the engine spin the turbine inside the exhaust port. The shaft transfers the rotation to the intake turbine. The intake turbine pushes more air into the engine (boost). As more air enters the engine, the car computer add