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Worst Gas Mileage after battery change

Hey,

I have a 2001 Hyundai Sonata. I change the car batter myself. After change the battery I drove like 50KM. I notice I got the worst gas mileage ever. Now it’s getting an average like 2-3Km from a petrol liter. I got an average 10Km from a petrol liter. Is there any reset I should have done after putting a new battery?

Thank you.

No, you DID the reset by replacing the battery… I suspect you are using the car’s mileage calculations to determine your fuel use. THAT is what got reset and it takes a little while to properly update the actual mileage. It also resets the “learned” values for the engine and that can reduce mileage for a little bit until the cars computer “learns” your engine again.

You don’t need to do anything but be patient.

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Do you not reset the read out each time you fill the fuel tank . Changing the battery does the same thing . You need to reset the ( MPG-AVG speed - Trip Odometer ) and that will give you a better idea of your actual fuel usage for the type of driving you did on each time.

Also check your fuel usage the old fashioned way once in a while to see just how accurate the read outs are.

Is your check-engine light on? Does your car smell like gas (petrol) or rotten eggs after you drive it?

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You could have knocked out some other parts while doing the battery change.Did you remove anything else that was in the way to take out the battery? On mine I have to remove parts of the airbox assembly to gain access to the battery