I found when I reset my ECU after changing the MAF my car would behave very oddly, about 5 miles later it suddenly started running perfectly and 1400 miles later it not missed a single fire.
My dad found after he had a new battery fitted the car ran a lot better again the only explanation was the ECU was reset at the same time.
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>>BTW my Mazda would say there is 0 miles left when I can fit only 54 gallons in (about 10 gallons left).
Wow! some tank. ;>)
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It's in the trailer behind (converted caravan).
Oops I meant litres ;-) Good lets lighten up the backroom again.
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A quote from my Escort's handbook (yes, I actually went out to the car to get it):
"If the battery has been disconnected these vehicles may exhibit some unusual driving characteristics for approximately 5 miles (8 km) after battery reconnection. This is due to the automatic relearning of the engine management system to the actual engine and may be disregarded."
I gather the ECU fine-tunes the engine's running according to ambient temperature, air pressure (dictated to an extent by the car's altitude above sea level), octane rating of the fuel, engine wear and several other variables - once these values have been cleared it has to rely on a set of pre-programmed optimum values to run until it has accumulated enough vehicle-specific data to iron out any quirks.
It would seem that in your car's case the optimum values permit better fuel economy than the real-world ones, perhaps you should disconnect the battery briefly every 5 minutes? ;-)
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It would seem that in your car's case the optimum values permit better fuel economy than the real-world ones perhaps you should disconnect the battery briefly every 5 minutes? ;-)
A switch would facilitate this... but an odd feature is that the "Distance to run" and mpg are contradictory. The higher mpg displayed should result in a greater distance, not a shorter one. The fault has not corrected itself after about 200 further miles.
Incidentally, the flat battery resulted when she forgot to turn off the passenger vanity mirror light and the car was not used for several days. The RAC man deplored the fact that it did not turn off along with the ignition, as one would expect, and told me the same bad feature was found on numerous new cars.
She has been warned.
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A switch would facilitate this
It would have to be a pretty heavy-duty switch!! Plus you'd be constantly re-coding the radio. It is strange that the Range figure should reduce, perhaps battery removal recalibrates the fuel level sender too?
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You might have been doing 46mpg before the battery reset, it would just take a lot of driving at that economy to bring a 15,000 mile avg. of 40mpg up.
Over the year the economy changes depending on the weather and where you drive. I typically get better MPG in the warmer months too.
After a tank or 2 you may find it does drop down again. Its very easy for me to get 52mpg on parts of my journey which soon plummets as soon as i set off again in the morning through the maze of lights, junctions, roundabouts and school run mums.
I reset my ECU recently too, personally i didn't find any significant difference in MPG whether it was adjusting fuel mapping or not.
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Years ago I had some software upgrade to the ECU of my 307. When I went out to the car and started up the Range to Empty read about 280 (on a full tank) when it is normally about 650. I went back to the workshop and they said that this was perfectly normal, until some miles had been driven and ECU 'learned' the driving style, as pointed out in earlier posts.
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>>when I can fit only 54 gallons in (about 10 gallons left). >>
That must be a big Mazda...:-)
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Bathtub tom already highlights my error above ;-) And I joked I had a trailer.
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