Why the ecu make my tune run richer over time ?

[Sport-Tech]

^Hey, you're Canadian - you should be fluently bilingual, n'est-ce pas?

[NoFear99]

Originally Posted by number1Tango

from what ive heard not just form this vehicle but other as well, even when you reflash your ecu and get more power, over a given period of time it will start reverting back to how it used to be with the factory AFR. I could be wrong, its just what ive heard.

This theory is very interesting...

But I hope you are wrong because that mean all Ecutek folks are wasting their monney.

[NoFear99]

Originally Posted by Sport-Tech

^Hey, you're Canadian - you should be fluently bilingual, n'est-ce pas?

Je me débrouille . I try to speak with mon tête !

[NoFear99]

Originally Posted by FA20Club.com

why dont you send me the log since you just installed the over pipe and i was expecting your log anyway

You want me to send you the log I did today where I'm fully rich or you want me to send you a log after a fresh reflash with a better normal afr reading ?

Which one is more valuable for you to know if you have some corrections to do or not ?

[Fast_Freddy]

Originally Posted by number1Tango

from what ive heard not just form this vehicle but other as well, even when you reflash your ecu and get more power, over a given period of time it will start reverting back to how it used to be with the factory AFR. I could be wrong, its just what ive heard.

That only applies to closed loop AFR changes made with a piggyback. The ECU can and will override any attempts to change the CL AFR from the 14.7:1 target value. Open loop AFR can be modified but is also subject to some ECU changes due to closed loop fuel trim changes. That's why it's so important to zero out your fuel trims before you start tuning.

Originally Posted by NoFear99

This thread you are refering me seem very interesting but too complicated for me especially when English is not your language.

May be somebody could explain here what this thread is all about in a simple short summary...

I'll try to simplify this as much as I can but I'm not sure if it will help.

The ECU sees how much air is entering the engine via the MAF sensor and looks at a preset table to determine how much fuel to add in order to achieve the target AFR. The ECU then reads the O2 sensor to see if the AFR is correct. When the O2 sensor AFR is too lean, the ECU applies a positive short term fuel trim (STFT) to richen the mixture to reach the target value. If, for instance, the ECU always has to add 10% extra fuel at a given set of conditions, it will set a long term fuel trim (LTFT) of +10% which essentially adds 10% to the lookup table value.

Now your tune may start out with a LTFT of 0 and that equates to 13:1 AFR but after some learning time the ECU sets a LTFT of +10%, it will add 10% more fuel making your new AFR ~12:1.

I hope this helps. It's the best I could do in a short time.

[NoFear99]

Originally Posted by Fast_Freddy

That only applies to closed loop AFR changes made with a piggyback. The ECU can and will override any attempts to change the CL AFR from the 14.7:1 target value. Open loop AFR can be modified but is also subject to some ECU changes due to closed loop fuel trim changes. That's why it's so important to zero out your fuel trims before you start tuning.




I'll try to simplify this as much as I can but I'm not sure if it will help.

The ECU sees how much air is entering the engine via the MAF sensor and looks at a preset table to determine how much fuel to add in order to achieve the target AFR. The ECU then reads the O2 sensor to see if the AFR is correct. When the O2 sensor AFR is too lean, the ECU applies a positive short term fuel trim (STFT) to richen the mixture to reach the target value. If, for instance, the ECU always has to add 10% extra fuel at a given set of conditions, it will set a long term fuel trim (LTFT) of +10% which essentially adds 10% to the lookup table value.

Now your tune may start out with a LTFT of 0 and that equates to 13:1 AFR but after some learning time the ECU sets a LTFT of +10%, it will add 10% more fuel making your new AFR ~12:1.

I hope this helps. It's the best I could do in a short time.

Thanks a lot for this nice summary. It help a lot to understand how an ecu may act.

[FAER]

So basically we have to re flash every few weeks or so many miles to maintain our tunes?!?

[NoFear99]

For those of you who dont know it, 12.17 is the lowest AFR ( Richer ) reading ecutek may read.

So if you are seeing 12.17 everywhere, that means your car can be anywhere below that point.

[Fast_Freddy]

Originally Posted by NoFear99

Thanks a lot for this nice summary. It help a lot to understand how an ecu may act.

You're very welcome. BTW, I'm pretty sure that FA20Club.com wants the ECU adjusted "rich" data logs. They tune, the ECU adjusts, they re-tune and so on for a few times until harmony is achieved.

Originally Posted by FAER

So basically we have to re flash every few weeks or so many miles to maintain our tunes?!?

No, see above. You just have to send data logs back to your tuner after flashing the initial tune and allowing the ECU time to adjust to it so he can fine-tune for the changes the ECU has made. It should never be an endless cycle.

[wparsons]

Originally Posted by NoFear99

For those of you who dont know it, 12.17 is the lowest AFR ( Richer ) reading ecutek may read.

So if you are seeing 12.17 everywhere, that means your car can be anywhere below that point.

Just a clarification... EcuTek can read much lower, the limitation is the stock O2 sensor range. If you run an aftermarket wideband ecutek can read as low as the sensor can.

[ft_sjo]

Originally Posted by wparsons

Just a clarification... EcuTek can read much lower, the limitation is the stock O2 sensor range. If you run an aftermarket wideband ecutek can read as low as the sensor can.

Just for clarification on your clarification; the stock sensor can read outside that range too, they just calibrated it down to 12.17. Chances are the margin of error between different sensors was too much below this point, or it just didn't matter and they wanted resolution over range.

[Dynotronics1]

Originally Posted by NoFear99

For those of you who dont know it, 12.17 is the lowest AFR ( Richer ) reading ecutek may read.

So if you are seeing 12.17 everywhere, that means your car can be anywhere below that point.

that's not quite correct. The STOCK program is only scaled down to 12.17. A simple reset of the scalar will net you correct readings down to 10.5 with no loss of resolution.

OP, you might want to log injector PW on that to really see where you are. I would bet your pig rich based on a few other parameters I'm seeing on that log

[ft_sjo]

Originally Posted by Dynotronics1

that's not quite correct. The STOCK program is only scaled down to 12.17. A simple reset of the scalar will net you correct readings down to 10.5 with no loss of resolution.

OP, you might want to log injector PW on that to really see where you are. I would bet your pig rich based on a few other parameters I'm seeing on that log

That's amazing. You can increase the range, whilst not losing resolution. Please let us into your secret on how ADC's work like this.

[King Tut]

I know on my FA20Club FI tune, the AFR is scaled down to 11.02 I believe, but there is no reason to lose the resolution on an NA tune.