High Fuel Consumption ..The Exhaust (2)

The oxygen sensor's voltage signal is monitored by the on-board engine management computer to regulate the fuel mixture. When the computer sees a rich signal (high voltage) from the oxygen sensor, it commands the fuel mixture to go lean. When it receives a lean signal (low voltage) from the oxygen sensor, it commands the fuel mixture to go rich. Cycling back and forth from rich to lean averages out the overall air/fuel mixture to minimize emissions and to help the catalytic converter operate at peak efficiency, which is necessary to reduce hydrocarbon (HC), carbon monoxide (CO) and oxides of nitrogen (NO_X) levels even further.

The performance of the Oxygen sensor tends to diminish with age as contaminants accumulate on the sensor tip and gradually reduce its ability to produce voltage.  The sensor may also fail prematurely if it becomes contaminated with lead from leaded gasoline, phosphorus from excessive oil consumption or silicone from internal coolant leaks or using silicone sprays or gasket sealers on the engine, sulfur, oil ash and even some fuel additives.. Environmental factors such as road splash, salt, oil and dirt can also cause a sensor to fail, as can mechanical stress or mishandling

High Fuel Consumption ..The Exhaust (1)

So far, we have talked about how cars take in air, its effect on fuel consumption, spark plugs (see earlier posts). Now in this post, we would be dealing with another ignored part of the car that affects fuel consumption a great deal. Just as cars breathe in, they also breathe out. through the car exhaust. The aspect is of great importance as the air that comes out of the car exhaust, if not checked, can be harmful to us humans as we breathe the same air. In order to make sure that the harmful gases are eliminated, the Oxygen Sensor (to check the air/fuel mixture) and the Catalytic Converter (to break down this harmful gases to water (H₂O) & carbon dioxide (CO₂)) are placed along the exhaust pipe. Hence the reason you see droplets of water from the exhaust pipe. Lets start with the oxygen sensor...

Tyre Marks explained

The purpose of the writings that you'll see on the sidewall of your tires is to help you identify the size and specification of the tires correctly and to confirm that the tire has been tested and approved to European and other country safety standards. Each car uses a certain tire specification always stated in the manual. The letters and numbers on the side of your car tires relate to their size, dimensions, composition and capabilities.

Let us take 165/65 R14  79T as an example as shown:

     165 - Tyre width in mm
     65 - Tyre sidewall profile – sidewall height expressed as a percentage of its width
     R - Radial (rather than a cross ply)
     14 - Diameter of the wheel rim, in inches
    79 - maximum load carrying capacity per tire, in this case equates to 437 kg (see charts below)

    T - equates to a speed rating of 190 km/h (approximately 118 mph)  (see charts below)

Fuel Consumption and your Car tires...

When was  the last time you checked your tire pressure YOURSELF? This is another often-overlooked item, and one that should always be on the list. Your tires are everything when it comes to your vehicle, and gas mileage is no exception. The rolling resistance of your vehicle has a direct effect on your fuel economy. The type of tire you use has a direct effect on fuel economy. Some tires are better than others; some have less rolling resistance. You might spend more for better tires, but in the end, you will likely come out on top based on your fuel savings alone.

As for what you should set the pressure at, check your owner’s manual or the tire sticker that should be located somewhere on your vehicle. There are a lot of places they put these things. Mostly I see them around the inside of the driver's door, or sometimes on a sticker in the glove box. Occasionally I find them under the hood. The important thing is to find it and set your tires to that spec.

How does Spark plugs affect your Fuel consumption?

The spark plugs are the business end of the ignition system. They are an integral part of your vehicles motor as they provide the much needed spark that ignites the air and fuel mixture within the cylinders. This continuous ignition is what keeps your car moving on the road. No spark means no combustion, wasted energy, increased emissions, loss of performance, idle roughness, hesitation, hard starting and possibly even a no start if all of the plugs are affected. Spark plugs are normally a wear and tear kind of part instead of an "all or nothing" kind of failure. Over time, they get worn or build up deposits from years of use and they become less effective and efficient.  I have rarely ever heard of a spark plug failing 100% all of a sudden. As it wears out, it would contribute to reduced gas mileage (increased fuel consumption), rough idle, and sluggish performance. They recommend them to be replaced at a certain interval, every 30,000 miles, to keep top running performance. It is a very common part of a "tune up"