Fuel Mileage - best page 2
Improper engine temperature will cause an engine to burn excessive fuel . If the engine runs too cool the fuel will not vaporize properly and this will cause the cause the engine to be less efficient and very hard on fuel . If the engine runs too hot it can cause the PMC to increase the amount of fuel it feeds to the engine to help to control the high engine cylinder temperature , causing heavy fuel consumption . Too hot an engine will also cause internal engine damage and premature engine failure .
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The cooling system should be kept in good working order , radiator , water pump , thermostat and hoses etc , too help keep the engine performing properly and to help maintain good fuel mileage and long engine life .
Failed engine control sensors or components will cause lower fuel mileage . These failures are often accompanied with a noticeable drivability concern , such as a lack of power , engine miss , surging , hesitation , etc and are often accompanied by a check engine light on .
If a sensor fails to supply the proper information to the Powertrain Control Module , The PMC will go to a built in strategy to compensate for the lack of data from that sensor .
This strategy may include a rich fuel mode to protect the engine cylinders against excessive cylinder temperature . Any sensor that effects the engine operation can effect the fuel mileage . For example the exhaust oxygen sensor monitors the amount of un burned fuel in the and oxygen content in the exhaust and feeds information to the PMC . The PMC uses that information to feed the proper amount of fuel to the fuel injectors and to the engine .
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Also the throttle position sensor , the engine temperature sensor , the crankshaft position sensor or cam shaft position sensor and others all effect the fuel mileage of a vehicle . If any of these fail , a rich fuel mode strategy may result .
An engine electronics diagnosis test will find inoperative sensors or other parts and then replacement of the failed parts will cure the problem .
The air intake system normally consists of an air duct from outside air to the air cleaner (filter housing) , the air cleaner , and , an air hose from the from the air cleaner to the throttle body . Some models may also use a mass air flow sensor between the air filter housing and the throttle body . If there is any air leak present in the connections or through the parts it can result in improper information to the PMC , and could cause poor engine performance and poor fuel mileage . The reason you want cooler outside air fed into the engine of the vehicle , rather than hot air from under the hood , is the higher density of the cooler air . Cool thick air will expand to a greater volume than thin hot air , under the heat of combustion while only using the same amount of fuel and more distance will be traveled on that fuel . (less throttle to go more distance). Did you ever notice that your car seemed to have more power on cool damp days than on warm or hot days ? Its not your imagination , the engine has more power . The air density is thicker on cooler days . You don’t have to push the accelerator down as far to do the same speed and therefore you use less fuel . (are you confused yet?) Believe it , cooler outside air will give more power and much better fuel mileage than hot under hood air !
Be sure to keep the air intake system properly sealed and free of any restrictions for best fuel mileage .
In winter the cool air does give better fuel mileage , but this is off-set by the long idle time to warm the vehicle up and to keep it warm . Also the power required to run the heater fan causes the alternator to work harder and the engine to consume more fuel . In summer running the air conditioning also causes the alternator to work harder and the engine will use more fuel .
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