hey, i have been modding my car for the last year or so and i want to clear the computer to make sure that i am getting the most out of my mods. Can i do this by just uunplugging the battery for a while?, or do i have to do something else too?

 

On my 91' NA if you unplug the battery for 30 min (or possibly less) then the ECU is reset. Mine always runs a little different for a while after it's been reset. I don't know that you have to really reset it for mods though although I'm not sure. I've never bothered with it much although I have reset it a time or two.

-Derek

 

Unplug the battery and pump the brake pedal a few times.

 

What, I would like to hear an explanation on this one.

 

You want to clear any stored power in the capacitors of the ECU and CPU, buy pumping the brakes (or turning on the lights) you dump any residual voltage.

You would also want to do this if you had a 'vert and were removing the airbag, as the ford built airbag controller stores about 5 minutes worth of charge otherwise.

 

I thought by reseting the ecu it causes all the trouble codes to reset. So say you were running rich and got an O2 sensor code, just replacing the sensor won't solve the problem until you removed the code from the ecu memory. I'm pretty sure on this part but 86-88 ecus can't be reset or by unplugging the battery and waiting won't work cause those ecus don't retain trouble codes. Everything just resets when you turn the key off. 89+ ecus have the ability to retain trouble codes. As for making the full use of your mods by the ecu. That stuff can't be changed by resetting the ecu unless the lack of perfromance was due to a bad part that was causing the subpar perfromance as in the O2 sensor example above. The only way for you to fully utilize your mods with the stock ecu is to send it out to be reprogrammed. You listed your current mods as intake and catback system. Your stock ecu is capable of handling the fuel requirements for those mods.

 

The main purpose or resetting IS to erase codes. In my understanding, if the sensor output is not withing the specs that the ECU is expecting, it will ignore the signal and resort for a "failsafe" value. It will continue in failsafe untill the signal is within spec again- I don't believe you have to reset the ECU for it to recognize a repalce faulty component- But if you have a 89+ you don't want the check engine light on all the time.
I find it is a good idea to reset the ECU anyways when making modifcations, and fuel/timing/etc adjustments, since the ECU does compensate for things and adjust over time.

And BTW, on my 90, it only takes about 2 minutes of power-off time to clear the ECU.