The Camshaft Sensor
The camshaft sensor is mounted on the camshaft. Its purpose is to generate a signal that indicates the top dead center on the vehicle’s number 1 cylinder. The electronic control module (ECM) uses this information to manage the fuel injection at the proper time and it also detects misfires. When the camshaft sensor fails, the sensor will not be able to supply the information to the ECM as it should and the computer will make a best guess. This is evident in an engine that will still run, but it has little performance when you step on the gas and the fuel mileage will drop considerably low at the same time.
The crankshaft sensor in an internal combustion engine monitors the location of the crankshaft in the engine. It uses this information to fine-tune the amount and timing of a fuel-injected engine. The crankshaft sensor uses electric induction to detect the precise position of the shaft. It will then send the information that it gathers to the vehicle’s computer. The sensor is placed directly next to the crankshaft, which has several pins in it. Each pin is an equal distance apart and near the crankshaft is a strong magnet. The combination of the pins and the magnet creates a constant magnetic field. When the crankshaft is spinning, the rotating pins cause a fluctuation in the magnetic field. The magnetic oscillation is what the crankshaft sensor uses to determine the shaft’s speed and position. If you have a faulty crankshaft sensor, the computer is unable to make fine-tuned adjustments and your engine will lose power and fuel efficiency.
The Ignition Coil
The ignition coil is a major part of every vehicle’s ignition system. It functions as an induction coil the converts the vehicle’s 12 volts from the battery into several thousand volts that are necessary to jump the spark plug gap and in doing so it ignites the engine’s air to fuel mixture for fire. Older ignition systems use one coil for the spark to all cylinders and newer ignition systems use one coil for each cylinder. Signs of a faulty ignition coil are the engine misfiring, idling roughly and a loss of power and acceleration as well as reduced gas mileage. In some cases, the engine will actually stall. Other symptoms of a faulty ignition coil are that the check engine light is illuminated on the dashboard or the car won’t start at all if there is no spark at all.
The MAF Sensor
A mass airflow sensor (MAF) reports the amount of air that is entering the engine to the power train control module (PCM). The PCM uses this gathered information to calculate the engine load. The most common design of a MAF sensor is the hot wire sensor. It includes one wire that is heated and another that is not. The microprocessor or computer in the MAF measures the amount of air flowing into the engine by how much current is needed to keep the hot wire about 200 degrees hotter than the cold wire. The MAF will increase or decrease the current to the heated wire when it senses a change, which will, in turn, cause the engine to gee more or less air as an adjustment. Symptoms of MAF failure are the engine running rich at idle or lean under a load, constantly running rich or lean and a rough idle or start.
The VVT Solenoid
The variable valve timing (VVT) solenoid uses electronic technology to apply variable electronic signals from the information gathered from the ignition system to a VVT solenoid. The VVT solenoid is responsible to control the flow of oil to the VVT system when it is engaged. The VVT system will activate when the vehicle is operating under load, with additional weight, accelerating or traveling up hills. When the solenoid activates, it sends oil to lubricate the variable valve timing chain and gear assembly. If the VVT solenoid fails, the timing chain and gear will wear out prematurely or break.
The best replacement for sensors, coils and solenoids are high quality and OE accurate to improve engine operation under high heat, so they are longer lasting than lower quality parts.