Replace battery now miles per tank is way down

[jsward12]

Hi, I just replaced the original battery in my 06 V6 sport. When I connected everything back up I noticed that the miles remaining on my tank of gas went from 120 miles to 90. Then I filled up the next day, I noticed that the last tank of gas showed 404 miles, when I filled up post battery replacement it was 334. I know that the ECU goes through a period of relearning everything, from people past experience have you experienced the same thing? How long does it take to get the MPG back to where it was prior to the ECU being reset?

Thanks in advance!!

 

[CruiseDuck]

The same thing just happened to my 2005 4Runner after I had the battery changed. The mileage use to show 456 miles to go after a fill up and now both times I have filled up after the battery replacement the miles to go shows 334. Same as yours.
Strange!

Hopefully someone will have an answer.

 

[eskimochaos]

The same thing just happened to my 2005 4Runner after I had the battery changed. The mileage use to show 456 miles to go after a fill up and now both times I have filled up after the battery replacement the miles to go shows 334. Same as yours.
Strange!

Hopefully someone will have an answer.

When you unplug the battery, the ECU looses its memory, It will take up to 500 miles for it to reconfigure.

Youll be fine trust me

 

[mslim]

What's happening is your trip computer thingy that figures your range by using average mpg and the amount of fuel in your tank, has just essentially been zero'ed by the battery disconnect. I just put a new battery in my '04 and my avg mpg went from 18.9 to 13.9. It's looking at a smaller sample of miles to average the fuel consumption against. The more you drive, the more realistic your range figure will become.

 

[eskimochaos]

What's happening is your trip computer thingy that figures your range by using average mpg and the amount of fuel in your tank, has just essentially been zero'ed by the battery disconnect. I just put a new battery in my '04 and my avg mpg went from 18.9 to 13.9. It's looking at a smaller sample of miles to average the fuel consumption against. The more you drive, the more realistic your range figure will become.

Mississippi Slim
'04 V8

Thanks for digging up an oldie. I reset the ave mpg after each tank...dont you?

 

[mslim]

Thanks for digging up an oldie. I reset the ave mpg after each tank...dont you?

Love your avatar eskimo. She reminds me of a girl in a movie I shot.

No actually I don't reset after every tank. I get bummed looking at the low mpg driving around town and sitting at stoplights. I like a big sample that includes some freeway miles. My V8 runs around 18.7-19.3 mpg with a big sample of mixed miles. 21 roughly w/ open highway running at the speed limit.

 

[eskimochaos]

Love your avatar eskimo. She reminds me of a girl in a movie I shot.

No actually I don't reset after every tank. I get bummed looking at the low mpg driving around town and sitting at stoplights. I like a big sample that includes some freeway miles. My V8 runs around 18.7-19.3 mpg with a big sample of mixed miles. 21 roughly w/ open highway running at the speed limit.

I just feel after a while, it wont change THAT much based on any driving conditions. I'd reset every 1k or so if I were you.

To each is own.