bigbob13 Posted July 13, 2010 Report Share Posted July 13, 2010 So this weekend, I took my wife's 07 edgeSEL AWD in for oil service at around 50k miles. While there, they tested the battery and warned me it was nearing the end of its life. The stock motorcraft battery had always had a large build up of acid on both posts, but i never did anything about it. I quickly learned this weekend that the acid had actually fused the positive terminal to the post. After some gentle persuasion (a.k.a. a hammer, chisel, screwdriver, pry bar, etc.) and a replaced battery terminal, i managed to get the new battery in place. Now today I drove it to work (roughly 40 miles each way) and noticed that the computer seems to be reading the fuel economy very erratically. Started my trip at 20.5 mpg and quickly dropped to 19.4 in the first few miles of my trip. got as low as 18.1 throughout the day and night of driving it. Sitting in a drive through idling and it changed 0.2 mpg in two minutes. I definitelt drive with a heavy foot, but i have nevered noticed it change this quickly. Similarly, the avg mph also started out at around 54 mph which seemed very high this morning, but eventually tapered back down the 34 throughout the day. I did perform the fuel trimming procedure to "relearn" the computer as specified in the owners manual. Not sure if this is all related or not. not sure if i have done something wrong??!?!!? please help Quote Link to comment Share on other sites More sharing options...
akirby Posted July 13, 2010 Report Share Posted July 13, 2010 So this weekend, I took my wife's 07 edgeSEL AWD in for oil service at around 50k miles. While there, they tested the battery and warned me it was nearing the end of its life. The stock motorcraft battery had always had a large build up of acid on both posts, but i never did anything about it. I quickly learned this weekend that the acid had actually fused the positive terminal to the post. After some gentle persuasion (a.k.a. a hammer, chisel, screwdriver, pry bar, etc.) and a replaced battery terminal, i managed to get the new battery in place. Now today I drove it to work (roughly 40 miles each way) and noticed that the computer seems to be reading the fuel economy very erratically. Started my trip at 20.5 mpg and quickly dropped to 19.4 in the first few miles of my trip. got as low as 18.1 throughout the day and night of driving it. Sitting in a drive through idling and it changed 0.2 mpg in two minutes. I definitelt drive with a heavy foot, but i have nevered noticed it change this quickly. Similarly, the avg mph also started out at around 54 mph which seemed very high this morning, but eventually tapered back down the 34 throughout the day. I did perform the fuel trimming procedure to "relearn" the computer as specified in the owners manual. Not sure if this is all related or not. not sure if i have done something wrong??!?!!? please help When you replaced the battery it reset the mpg and mph averages. It's normal. It will stabilize as time goes on. Quote Link to comment Share on other sites More sharing options...
ablb Posted July 13, 2010 Report Share Posted July 13, 2010 I reset our MPG meter at every fill up. I just luv to watch the meter change from 6 to 8, 10, 12, 13 then I REALLY llike to watch it drop at the first light (it’s always red ) 13, 11, 9, 7 then off we go again 7, 9, 11 then it’s time to stop at the NEXT (it’s also always red ) light, etc., etc., and ETC (THEY ARE ALL ALWAYS RED ). Welcome to Ft. Worth, Texas 1 of the top 10 WORST cities in the US for coordinated lights. :wacko: HHhMMm maybe that’s why we only average 15.5 to 17.5 mixed in town, lots of freeways (now that’s an oxymoron (we (Texas) have the HIGHEST # of new toll rd miles))!! ab Quote Link to comment Share on other sites More sharing options...
bbf2530 Posted July 13, 2010 Report Share Posted July 13, 2010 (edited) So this weekend, I took my wife's 07 edgeSEL AWD in for oil service at around 50k miles. While there, they tested the battery and warned me it was nearing the end of its life. The stock motorcraft battery had always had a large build up of acid on both posts, but i never did anything about it. I quickly learned this weekend that the acid had actually fused the positive terminal to the post. After some gentle persuasion (a.k.a. a hammer, chisel, screwdriver, pry bar, etc.) and a replaced battery terminal, i managed to get the new battery in place. Now today I drove it to work (roughly 40 miles each way) and noticed that the computer seems to be reading the fuel economy very erratically. Started my trip at 20.5 mpg and quickly dropped to 19.4 in the first few miles of my trip. got as low as 18.1 throughout the day and night of driving it. Sitting in a drive through idling and it changed 0.2 mpg in two minutes. I definitelt drive with a heavy foot, but i have nevered noticed it change this quickly. Similarly, the avg mph also started out at around 54 mph which seemed very high this morning, but eventually tapered back down the 34 throughout the day. I did perform the fuel trimming procedure to "relearn" the computer as specified in the owners manual. Not sure if this is all related or not. not sure if i have done something wrong??!?!!? please help Hi bigbob. :D As akirby stated, disconnecting/replacing the battery completely wiped out all previous mileage memory and readings. So instead of the mileage being based on all previous miles accumulated (or since the last time you reset the mileage to zero), it is only being calculated based on the few miles you have driven since the battery was reconnected. It is similar to the day you first drove the car off the Dealers lot with 10 (or however many) miles on it. Therefore, the mileage will rise and fall very quickly, in direct relationship to your current driving environment until you have put more mileage on the vehicle again. You will quickly begin to see the mileage stabilize as the miles go by. It is the same story with the "Average MPH" readings. Also, in case you do not own one (which if you were using hammers, chisels, screwdrivers and prybars :eek5: I assume you do not): There is a battery terminal puller that should be in the tool box of anyone who owns a car. It looks like a funky little type of mini-vice and only costs a few bucks in most auto stores. Just pop it on the terminal, turn the vice screw and off she comes. Along with a battery terminal brush/cleaner, it will save a lot of "gentle persuasion" (along with money, busted knuckles, broken terminals etc.) in the future. Good luck. :beerchug: Edited July 13, 2010 by bbf2530 Quote Link to comment Share on other sites More sharing options...
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