How flexible is the ECU?

semtex · 06-18-2009, 11:14 AM

Shumby, fyi I tried that procedure (you sent it to me before). I couldn't get it to work, so I just gave up and disconnected the battery. Not that this should stop anyone else from trying it, mind you. Maybe I was just too impatient or couldn't get the timing right (even though I tried 5 times).

ZKindaGuy · 06-18-2009, 11:16 AM

Quote:

Originally Posted by shumby

.......
Also some like to take the car out and run it hard around 3times. Basically 1st through 3rd like you are racing. Of course this sounds kinda weird , I dont know if to believe this. But it cant hurt and it sounds logical , so it doesnt get some weak run and try to learn from that , you immediatly feed it some hard runs to set it self to and you should be good.......

Actually this approach is the best one to perform. However I would like to suggest it be done in the following way for it is much better for ECU map relearning:

Take the car out and drive it at least 20 minutes in city driving conditions and 20 minutes in highway conditions. When doing highway driving vary the acceleration between cruise and sudden acceleration conditions.

That's all....

semtex · 06-18-2009, 11:17 AM

I forgot to mention re. the radio presets -- I just jot down all my settings on a notepad before disconnecting. In fact, I saved that sheet of paper in my toolbox for future use. Besides the radio presets, there are a few other things that are a good idea to jot down, like audio settings, bluetooth volume, shift indicator rpm (if you have something different than default), and a reminder that after reconnecting the battery, SRM is off by default and you'll need to turn it back on (if so desired). Interestingly, the battery disconnect does not wipe out the XM presets for some reason. Only the regular radio stations get wiped.

RCZ · 06-18-2009, 01:17 PM

I chuckle every time i see Shumby post that ridiculous resetting method. Then I laugh even more when I see "its all about timing" after it. Its so much easier to to just unplug the battery and pump the brakes a couple times.... also you don't really even NEED to unplug the battery...the ECU will adjust anyway...

To answer the original post...you can put all that stuff on without resetting the battery. However if you are installing the Stillen G3's...I would disconnect it since you are going to be working near airbag sensors...and you cant reset those when they go off....

Modshack · 06-18-2009, 01:47 PM

Quote:

Originally Posted by RCZ

also you don't really even NEED to unplug the battery...the ECU will adjust anyway...

To answer the original post...you can put all that stuff on without resetting the battery. ....

Long term fuel trims will re-adapt to whatever you do within 20 miles or less.... The Eproms are constantly updated with data that establish the fuel trims..

semtex · 06-18-2009, 01:51 PM

Quote:

Originally Posted by Modshack

Long term fuel trims will re-adapt to whatever you do within 20 miles or less.... The Eproms are constantly updated with data that establish the fuel trims..

Agreed. But if you're planning to put the car back on the dyno shortly after installing the mod, it doesn't hurt to reset the ECU just to expedite the adaptation process a little either.

6SPD_FTW · 06-18-2009, 05:53 PM

I'm not certain, but 20 miles is a bit short for the ECU to re-learn fuel trims. It usually takes a full 200-300 miles for full re-learning. And WOT acceleration doesn't do ANYTHING at all for helping the ECU re-learn fuel trims. The ECU goes into open-loop at WOT and completely ignores the AFR sensors and doesn't tune the AFR at all. Only at idle or part-throttle does the ECU pay attention to the AFR sensors.

As far as the ECU reset procedure above, it may be good to learn it...

The idle-air relearn procedure is accomplished the SAME way as above. The only difference is on the last step, when you floor the gas pedal and the SES light starts flashing after 10 seconds, if you RELEASE the accelerator pedal, the SES will flash out error codes (0000 is no faults), if you stomp the accelerator pedal, it will clear the ECU fuel trims. HOWEVER, if you do NOT release the acc. pedal and continue to hold it down for a full 20 seconds, the SES will stop flashing and turn ON. If you start the engine within 3 seconds, the ECU will perform the idle air relearn. That will be important for any mods to the air induction system.

Conditions that must be met: engine at operating temp, steering wheel straight ahead, all accessories off, doors closed, transmission in N and parking brake set.

Late,
Trav

Modshack · 06-18-2009, 06:04 PM

Quote:

Originally Posted by 6SPD_FTW

I'm not certain, but 20 miles is a bit short for the ECU to re-learn fuel trims. It usually takes a full 200-300 miles for full re-learning. And WOT acceleration doesn't do ANYTHING at all for helping the ECU re-learn fuel trims.

Doesn't take that long. I've got real time monitoring of the STF and LTF trims up on a screen (scangauge) all the time..I just put new intakes on the car and drove 5 miles and observed a 2% change in LTF's....from fat rich stock at -11% to -9% (still rich)

Modshack · 06-18-2009, 06:08 PM

Quote:

Originally Posted by semtex

Agreed. But if you're planning to put the car back on the dyno shortly after installing the mod, it doesn't hurt to reset the ECU just to expedite the adaptation process a little either.

One of the problems I have with typical dyno testing. It takes a bit longer than a dyno pull or 3 to fully adapt..

ZKindaGuy · 06-19-2009, 12:25 AM

Quote:

Originally Posted by 6SPD_FTW

I'm not certain, but 20 miles is a bit short for the ECU to re-learn fuel trims. It usually takes a full 200-300 miles for full re-learning. And WOT acceleration doesn't do ANYTHING at all for helping the ECU re-learn fuel trims. The ECU goes into open-loop at WOT and completely ignores the AFR sensors and doesn't tune the AFR at all. Only at idle or part-throttle does the ECU pay attention to the AFR sensors.

As far as the ECU reset procedure above, it may be good to learn it...

The idle-air relearn procedure is accomplished the SAME way as above. The only difference is on the last step, when you floor the gas pedal and the SES light starts flashing after 10 seconds, if you RELEASE the accelerator pedal, the SES will flash out error codes (0000 is no faults), if you stomp the accelerator pedal, it will clear the ECU fuel trims. HOWEVER, if you do NOT release the acc. pedal and continue to hold it down for a full 20 seconds, the SES will stop flashing and turn ON. If you start the engine within 3 seconds, the ECU will perform the idle air relearn. That will be important for any mods to the air induction system.

Conditions that must be met: engine at operating temp, steering wheel straight ahead, all accessories off, doors closed, transmission in N and parking brake set.

Late,
Trav

The ECU relearns in 60 miles.

06-18-2009, 11:14 AM	#16 (permalink)
semtex A True Z Fanatic Join Date: Jan 2009 Location: Behind enemy lines Age: 54 Posts: 5,995 Drives: People to drink Rep Power: 32	Shumby, fyi I tried that procedure (you sent it to me before). I couldn't get it to work, so I just gave up and disconnected the battery. Not that this should stop anyone else from trying it, mind you. Maybe I was just too impatient or couldn't get the timing right (even though I tried 5 times). __________________ "There are no small accidents on this circuit." -- Ayrton Senna 316.8whp & 248 ft/lbs (Dyno Dynamics) \| 319whp & 256 ft/lbs (DynoJet) (04/23/10) Stillen G3 CAI, CBE, Pulley / F.I. LTH / GTSpec Ladder Brace / Setrab Oil Cooler / UpRev-tuned by Forged Perf.

06-18-2009, 11:17 AM	#18 (permalink)
semtex A True Z Fanatic Join Date: Jan 2009 Location: Behind enemy lines Age: 54 Posts: 5,995 Drives: People to drink Rep Power: 32	I forgot to mention re. the radio presets -- I just jot down all my settings on a notepad before disconnecting. In fact, I saved that sheet of paper in my toolbox for future use. Besides the radio presets, there are a few other things that are a good idea to jot down, like audio settings, bluetooth volume, shift indicator rpm (if you have something different than default), and a reminder that after reconnecting the battery, SRM is off by default and you'll need to turn it back on (if so desired). Interestingly, the battery disconnect does not wipe out the XM presets for some reason. Only the regular radio stations get wiped. __________________ "There are no small accidents on this circuit." -- Ayrton Senna 316.8whp & 248 ft/lbs (Dyno Dynamics) \| 319whp & 256 ft/lbs (DynoJet) (04/23/10) Stillen G3 CAI, CBE, Pulley / F.I. LTH / GTSpec Ladder Brace / Setrab Oil Cooler / UpRev-tuned by Forged Perf.

06-18-2009, 01:17 PM	#19 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1119	I chuckle every time i see Shumby post that ridiculous resetting method. Then I laugh even more when I see "its all about timing" after it. Its so much easier to to just unplug the battery and pump the brakes a couple times.... also you don't really even NEED to unplug the battery...the ECU will adjust anyway... To answer the original post...you can put all that stuff on without resetting the battery. However if you are installing the Stillen G3's...I would disconnect it since you are going to be working near airbag sensors...and you cant reset those when they go off....

06-18-2009, 05:53 PM	#22 (permalink)
6SPD_FTW Base Member Join Date: May 2009 Location: Bristol, VA Posts: 59 Drives: 09 370Z Bl 6MT Rep Power: 16	I'm not certain, but 20 miles is a bit short for the ECU to re-learn fuel trims. It usually takes a full 200-300 miles for full re-learning. And WOT acceleration doesn't do ANYTHING at all for helping the ECU re-learn fuel trims. The ECU goes into open-loop at WOT and completely ignores the AFR sensors and doesn't tune the AFR at all. Only at idle or part-throttle does the ECU pay attention to the AFR sensors. As far as the ECU reset procedure above, it may be good to learn it... The idle-air relearn procedure is accomplished the SAME way as above. The only difference is on the last step, when you floor the gas pedal and the SES light starts flashing after 10 seconds, if you RELEASE the accelerator pedal, the SES will flash out error codes (0000 is no faults), if you stomp the accelerator pedal, it will clear the ECU fuel trims. HOWEVER, if you do NOT release the acc. pedal and continue to hold it down for a full 20 seconds, the SES will stop flashing and turn ON. If you start the engine within 3 seconds, the ECU will perform the idle air relearn. That will be important for any mods to the air induction system. Conditions that must be met: engine at operating temp, steering wheel straight ahead, all accessories off, doors closed, transmission in N and parking brake set. Late, Trav