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Discussion Starter #1
When installing a CAI, is it necessary to disconnect the negative cable and then reconnect it after your done so the computer can relearn?
 

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I got another question to add to his question.

When you disconnect to reset your ECU does it erase your mileage?
 

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YES ALWAYS ALWAYS ALWAYS disonnect the battery for around 15-30minutes, id say 30 just to be sure, when you reset the ECU it erases the trip milage set but not the actual milage
 

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And either way you will disconnect the battery for a CAI so you can install it.

No it doesnt erase the mileage, its pretty hard to do erase the mileage my brother had to burn out a few electrical components to scre up the mileage on his car with a digital dash.
 

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u can swap intakes with out disconnecting the battery, none of its electrical, but u should reset the ecu after anything intake or exhaust related
 

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dosnt matter if its electrical or not, it is a good ide a, and it gets you in the habit, to get the most out of the modification you reset the ECU, of course use good judgment, for instance changing a motor mount will not require to reset it[:)]
 

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It shouldn't take more than a minute or two with the battery off, it isn't like there are some big capacitors built into the computer that hold enough to keep it powered for minutes on hand. Nevertheless, if you just disconnect your battery before you start and reconnect it when your done, that is easy enough.

Also it is good to let the engine idle for about 3-5 minutes after you reset the ECU before you take it out for a drive.
 

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why should i rest the ecu ?

i didnt rest mine....

so i wonder if that is the reason my focus seems to have a hole in the gas tank lately...

hummm

i dont know if this will work or not..
but i remember the way to reset the ecu for the probe was to disconect the batery, press the break pedal for a minute and thats it....

will this work with the focus?

thanks...

joel
 

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reset it so it can adjust your fuel curve with the new extra airflow....

the ecu in the focus has a short term memory, as do a lot of cars, that wont reset unless its without power for at least 20 minutes.

just unplug it for 20 and you will be fine joel
 

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just disconnect it, its not a big thing on minor mods, but just get into the habit of it, it does make a differnce, and id do it for a good amt of time, what it will it hurt for you to have keave it off for around 15-20 minutes, just to be sure
 

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ok..
ok..
i will go and unplug the battery now and leave it like that untill tomorrow morning....

thanks man !

Joel
 

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At least the stock radio seems to have a backup battery or it uses an EEPROM to store your presets. [;)]
 

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yeh its kind of a pain on mine, i have to reset them everytime i do engine work...
 

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No it's not too late. But it isn't really necessary. The ECU will eventually re-learn and adjust to the changes. With an exhaust change, it's possible you can throw a CEL within the first few minutes or miles and disconnecting will prevent that or reset it if it occurs.

John said:
Soo is it too late to reset mine if I got my cat back on earlier today?
 
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