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Old 01-06-2014, 11:54 PM   #34
smbrm
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Dssence


I would suggest the following:

1) the computer in the car makes changes to the timing based on many parameters. The reason the lower octane fuel gives poorer fuel consumption is that the car's knock sensor retards the timing when it hears knock due to the lower octane fuel. Once you get higher octane fuel in the car this should help fuel consumption from this perspective.

2) in the owners manual there will be section that describes the dash buttons and the two that are used to reset the odometer, select the odometers, select the outside thermometer, the average fuel consumption display, the instantaneous fuel consumption display etc. Read this section, understand it and figure out what buttons to push to change the display value you see and how to reset those that are resettable.

3) the average fuel consumption dash readout tends to show a little better than real life calculating the fuel consumption from the km. driven and the fuel added.

4) you should read and record the average fuel consumption, at refill time and then reset the average fuel consumption readout to zero. This will tell you what the computer thinks is going on. Record the odometer mileage since the last refill to full(keeping in mind the instructions on the inside of the gas cap regarding how full full is). Add fuel, and use the fuel amount added and the km. since last refill to measure the real world fuel consumption. You can then compare that to the computer readout to see the difference. Do this for 2-3 tanks of fuel( go down to 1/4 to 1/8 left in the tank before fill up).

5) Driving Style: fuel consumption from a driving style perspective will be a function of when you shift up and down and how much throttle you use. You can see the impact of throttle and shifting by setting the dash readout to instantaneous fuel consumption. It will read blank when stopped and change as you drive with how you use the throttle and shift, but go back to no value when ever you stop the car. The average readout will always show a number greater than zero until you reset it to zero. That is one way to tell the difference between the two read outs in addition to the fact that the average fuel consumption readout screen says avg and L/100 km while the instantaneous readout just shows L/100 km on the screen.

6) you will see some very high instantaneous fuel consumption readings as you accelerate but lower values when cruising. The shorter the duration of higher values and the more time at low values will result in better fuel consumption. If you are seeing real world fuel consumption worse than the worst at the fuely website for this car then you may have a problem. If you are in the range shown there then you probably just need to work on your driving technique to improve to the better end.


Try this for a few tanks of fuel and see what you learn about your car and fuel consumption.

Just a suggestion.

Please note that if you have the dash readout set to avg fuel consumption, your readout can show a higher value because the first thing you do after fill up is accelerate away which uses way more fuel (particularly if you are heavy on the throttle) than cruising on the highway. Over the time to next refill, the average should even out depending on the mix of city and highway driving. Remember the throttle is not an on/off switch! You are allowed to use less than full throttle to accelerate!!

Cheers
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