Why can't my car achieve its advertised fuel economy?

Our tech guru has the answers to your car questions
by Ferman Lao | May 14, 2014

Hi, Top GearI am a fan, and I find your articles very useful. I recently bought a 2014 Mitsubishi Adventure GLX. Before I bought it, I had been told that its gasoline mileage was 12-17km/L.

Now, I have been driving my Adventure for almost two months, and have had my first oil change. Upon computation, I learned that consumption is around 8-10km/L. I was told that mileage depends on driving habits or traffic condition, but I only usually travel from C5 in Makati to Bonifacio Global City in Taguig, which is about a 15-minute travel when there's no traffic jam.

Was I misled with the mileage claim, or is there something wrong with my car? If something is wrong with my car, what's the best advice you can give me so that I can have this fixed at a Mitsubishi service center?

Thank you in advance and more power!



Hi, Charles. There's probably nothing wrong with your Mitsubishi Adventure. More likely than not, the fuel consumption quoted to you by the sales executive would be the "best performance under favorable conditions" consumption. What those conditions are, only the sales executive or whoever supplied the data would know. However, it is true that driving habits play a big part in the final fuel consumption.

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There are some habits that you should break and some habits you should form to optimize your fuel consumption.

Many drivers have the bad habit of warming up their vehicles--particularly diesel ones--for far too long in the morning. That doesn't do much for the engine nor the environment, except consume more resources and expel more unnecessary pollutants. For our climate, your engine and the environment are better off if you start your trip within the first minute of starting your engine. Just don't subject your vehicle to sudden or heavy loads until it has reached the proper operating temperature. For most local vehicles, this will be within five minutes of first starting the vehicle and getting mobile.

Short-duration or short-distance trips also adversely affect fuel consumption. Driving frequently in stop-and-go situations likewise have the same effect.

Without knowing how you drive, I won't really be able to tell why your consumption reading is such. But to me, your consumption sounds about right. Perhaps other Adventure GLX owners can chime in.

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Interestingly, you raise a very good and timely question. As a consumer, I'm disappointed with the fuel-consumption figures quoted by almost all locally available car brands. These figures are unrealistic for most vehicle buyers' urban driving conditions.

More often than not, the quoted figures are a "best case" mileage scenario that's unlikely to be achievable in normal day-to-day driving conditions, leaving us all disappointed and feeling misled. In your case, the quoted consumption of 12-17km/L is also such a wide range in itself as far as consumption figures go, that it would be difficult for me to use it as any sort of basis upon which to make a buying decision.

Last February, the Car Awards Group held its first-ever Fuel Economy Benchmark (FEB) testing program. The activity aims to establish a local standard in testing for realistic fuel consumption, which will be useful to the car-buying public and the local automotive industry as a whole.

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The test conditions were as constant as possible with many uncontrollable variables removed, and the method of measuring fuel consumption was more accurate than the popular refill-at-the-pump method. The latter is practical and easy to do, and provides sufficient information for the car owner. But it should not be relied upon for any sort of industry-level testing.

Why? Primarily because it measures the amount of fuel that's put into the vehicle and not what is consumed for the distance traveled. The second reason is that the current testing method has more variables as well. Certainly, more accurate methods are available and better than the popular method.

The FEB test results, which will be available soon, much more closely reflect real-world, urban-driving fuel consumption than the more commonplace highway-driving consumption figures that most economy runs tend to favor. However, this isn't to say that the FEB test results should be taken as an absolute. The resulting figures still just serve as a fuel-consumption guide--albeit a better one. This is because the tests were conducted under conditions similar to the car buyers' everyday environment.

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How do you remove a coffee-like stain on a pearl-white car? I tried WD-40, kerosene and rubbing compound. They didn't work! Thanks.

Abi Posadas

Hi, Abi. It seems to me that some sort of corrosive chemical may have dripped onto your paint at one time and has permanently stained your paint beyond the protective clear coat. Some chemicals can penetrate paint and stain it permanently. Brake fluid is one such chemical; in certain instances, motor oil is another. Unfortunately, short of having the panel repainted, getting rid of the stain is not easy.


Best regards,

Ferman Lao
Technical Editor

Do car problems keep you awake at night? Send questions to topgear@summitmedia.com.ph.

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