The sensors are what makes a fuel injection system work. The throttle body setup is not complex and dosen’t need many sensors to work. The multipoint or multiport setup is far more complex and needs alot more sensors. The sensors tell the ecm or ecu (computer) how much fuel to inject into the engine and where the timing sould be at. Certain sensors enable different small maps to be enabled. Such as the coolant sensor calls the start up or enrichening map when a certain engine coolant temp has not been reached. Most sensors send a 0 to 5 volt signal back to the ecu. From this value the computer knows where the sensor is operating.
The coolant temperature sensor checks how hot the engine’s coolant is running. The coolant temp sensor is usually located on the intake manifold or the water inlet to the engine. This is usually close to or in the thermostat housing, which is at the end of the hose coming from the radiator. The sensor tells the ecu if the engine is cold and has not been warmed up. This activated the enrichening maps in the computer. It is essentially a “choke” for the engine. When engines are cold they need more fuel to run properly until they’ve heated up to a certain temp. Usually the normal fuel maps will be used when the engine reaches within 20 or 30 degrees below where the thermostat opens. That is why it’s important to not lower the thermostat temp or it could keep the engine running rich all the time, wasting fuel. If you have a problem with your coolant sensor you can test it. This test also works for a MAT (manifold air temp) sensor. First check the plug to make sure the wires look good and the plug is tight. Run the car for five minutes. Shut off the car and remove the sensors plug. You will need a volt/ohm meter to check the ohms. Set the ohm meter on 20k ohms. There are three types of temperature plugs. With a single wire sensor, touch the one wire and use the other wire to touch the brass or metal on the sensor. Two wire sensor, just touch the two wires. Three wire temp sensor, touch the center and one of the outers. The ohm value should be higher than 500 ohms or it is not good and needs to be replaced.
The air temp sensor simply checks the temperature of the incoming air. The sensor is usually located on the air box (filter area) or somewhere in the air inlet tube. The purpose of the sensor is to help with calculations of air density coming into the engine. The information is fed to the computer. If the air is warmer it’s less dense and requires less fuel for the engine to run at it’s correct air to fuel ratio. The engine needs more fuel at colder temps due to the denser air. The colder denser air gives the engine the ability to make more power, needing more fuel. The air temp sensor changes resistance with heat changes and will send the new voltage to the ecu. The car’s computer then changes the amount of fuel injected in the engine. If you have a problem with your air temperature sensor, you can test it. First check the plug to make sure the wires look good and the plug is tight. Run the car for five minutes. Shut off the car and remove the sensors plug. You will need a volt/ohm meter to check the ohms. Set the ohm meter on 20k ohms. There are three types of temperature plugs. With a single wire sensor, touch the one wire and use the other wire to touch the brass or metal on the sensor. Two wire sensor, just touch the two wires. Three wire temp sensor, touch the center and one of the outers. The ohm value should be higher than 500 ohms or it is not good and needs to be replaced.
A fuel pressure reguator maintains a certain pressure always. The fuel pressure regulator is usually located on the end of the fuel rail. The fuel rail covers the fuel injectors. The regulator has a fuel line running off it back to the fuel tank. The regulator has a little valve in it and pressure is controlled by the spring tension that keeps it closed. Simple adjustable regulators use a bolt that runs inside the regulator, to add tension on to the spring and valve. If the pressure is too high the fuel that escapes around the valve and returns to the gas tank. This always keeps the pressure constant. Adjustable fuel pressure regulators for turbo or supercharged vehicles are different. As the boost increases the demand for fuel becomes greater for the engine. To increase the fuel to the engine the fuel pressure is increased. The boost created by the compressor is fed to the back side of the valve. It is the same side as the spring. The increased pressure on the backside of the valve holds it shut more, increasing the pressure according to the boost. There is usually still an adjustment for the static or regular pressure.This allows the unboosted curve to be richened up.
The electric fuel pump is generally used on fuel injected cars. It has a relay under the hood, usually on the inner fender, which supplies 12 volts dc to the pump. It should click every time the key is turned to a forward position. The starter does not have to engage for this to happen. If someone turns the key forward for you, you will be able to hear it clicking under the hood, assuming it works. If it is clicking you can still check it. One of the leads should have no voltage then switch to at least 12 volts when the key is turned. This action primes the pump and builds fuel pressure up so the engine can start. The pump itself is usually located inside the gas tank, so that it is cooled down by the fuel. The fuel pump delivers about 7 psi to throttle body injected engines.
Many full electric cars have been made. Full electric vehicles have an underlying problem, that being the batteries. One issue is the amount of time needed to charge the batteries. This is not always an issue as technologies continue to improve. The battery weight has always been an issue and is always being improved. Major improvements have come from battery technologies in laptop computers. Price is also a large consideration, as lighter batteries tend to cost more. With weight comes two problems, lack of acceleration and lack of range. These problems can only be contradicted with a bigger motor and or more batteries. Range has generally really been the main problem with electric cars as the average car can go 300 miles. Where as an electric may have a range of 80 miles. Also people would not know where to plug in their cars, And would not want to have to wait for the car to charge . Here is where the hybrid offers such an advantage.