Many of you have suggested that after resetting the ECU it is beneficial to drive the car hard so that the car is reprogrammed to perform better ...i assume this is by different mixtures of air, gas etc?? The ECU takes around 200 to 400 miles to be fully reprogrammed and that seems like an awful long time to drive the car hard for consecutively especially all at once...anybody know how long would be beneficial???

 

just drive it like you normally drive it. the ECU will learn the mixture after a mod even if it sits and idles for a week.

 

My SES light came on about a week ago. Took it to Autozone and they said it was the code for the gas cap. He reset it, it came back on as soon as I started to car. I took my gas cap off and replaced back on. After about 3 day and about 60 or so miles, the light went off. I am guessing that the ECU will learn and reset itself in about 60 or so miles.

 

I think the ECU maps stuff across different RPMs... I always notice the Long Term Fuel Trim values change as you rev up/down (logging from an OBD-II scantool). So I guess it's beneficial to expose the ECU to different conditions (low load, high load, low RPM, high RPM, etc.) to let it learn everything. But I wouldn't really go out of your way to do this--I'd just drive it normally. The ECU will figure it out over time.

 

That has nothing to do with the ECU "learning" (in the sense that this thread is addressing; i.e. long term fuel trim values for influencing the short term fuel trim) and EVERYTHING to do with the ECU's procedure for activating/deactivating the SES light.
Chances are good the gas cap still wasn't tight (or there was some other type of EVAP emissions system leak) after he reset it, so it came back on. Then you re-seated the gas cap and the condition went away. I think it takes like 2 stop/starts of the engine (or the ECU, specifically) before the ECU will clear the SES after the condition disappears. That probably coincided with ~60 miles worth of driving for you.

 

I wonder what the ECU would think if someone bored out their intake manifold..

 

I think the ECU might get pretty pi$$ed off.

 

I'm a learning computer, if the car does not respond ..I will terminate it.

 

"Learning" ECUs are overrated. There is hardly any, if any difference at all. Your two feet (and a hand perhaps) are all that's needed to change how the car behaves.

 

Drive it hard until it blows up.

 

It would just be easier to steal a car and drive it rather than drive it like you stole it.

 

except for that whole stealing a car being illegal part

 

Its only illegal if you get caught.. Reminds me of this time I was at a party, and I went to this room and there was this girl asleep.. and then...

 

Sooner! I lover the placement of your radar.. Very smart.

 

its great except for when the cops still know you have it, Jason

 

When intalling a new mod you should always reset the ECU?

When I installed my intake I didn't do that......

I drove it like i RENTED it....hahahahah

 

lets say you take out the battery for like 20 minutes then put it back on, does that reset the ecu? or does it take 24 hours to reset?

 

From what my car inclined friends tell me it shouldn't matter how long you unplug it for but rather pressing everything you can inside the car (horn, radio) after the battery is unplugged to relieve the power....

 

what does that do?

 

Yes, unplug the negative battery cable, then hold the brake pedal down for ~5 seconds or so.

Why do you have to wait "24 hours" after disconnecting the battery? Because some of the electrical components in the vehicle contain capacitors (e.g. headunit), and they store power such that when you disconnect the battery, the component(s) inside the ECU that keep its long-term memory alive can continue to receive power from those capacitors, so the contents are still there after you reconnect the battery.

Using a higher-draw device (such as the brake pedal, which activates the brake lights) to quickly drain out those capacitors provides instant relief of the ECU's long-term memory so that it gets erased. This basically performs all the action that those "24 hours" of waiting would do, except MUCH quicker.

I've verified this with my OBD-II scantool... after disconnecting the battery and holding the brake pedal down for a few seconds, then reconnecting it (which results in an interesting "spark" at the terminal when it first touches; further evidence that you've drained some capacitors, since they're quickly recharging when the battery cable first touches) results in both Long Term Fuel Trim parameters being reset to 0.0%, along with the emissions information showing up as "incomplete" (ECU hasn't had enough time yet to determine how well the emissions components are working, since it has now forgot the old parameters)

 

so do you really think there is a need to "teach" the ecu after doing ^^^^^^^^?

 

just get a bucket of water, and pour over your motor, it helps it cool down and rests all the ECU, then you install a pentium 4 chip with a raid mother board and a phat graphics card, you'll be playing need for speed , trivial persuit in now time..

i have to confess --- i put regular gas in my car.. i am so depressed, i know i can be cheap,but thats crossing the line, i hope max forgives me :`(

 

LOL, you must be a computer guy....

 

00-01 it takes 24-25 HOURS for the ecu to reset assuming all power to it is disconnected. Doesn't matter what else your turn on, the ECU itself won't reset in 20 minutes as it has its own back up power unit which must be drained and that takes 24 hours or so.

02-03 cannot be reset by unplugging anything and you need to follow the instructions to do it. They've been posted around so look for em.

Resetting the ECU after each mod (yes including after you change your bulbs!) is totally dumb and does nothing.

 

I Dont get it, i wana reset my ecu on my 02.. in short of blowing up the car, whats the easiest way to reset it..?