HELP!! - Fuel Trims and O2 feedback
#1
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HELP!! - Fuel Trims and O2 feedback
Hi all,
I've recently got into the Ecuflash scene... I own an Mitsubishi Airtrek, a JDM SUV with an Evo 7 engine and INVEC II sequential gearbox.
I recently upgraded the turbo, injectors fuel pump and some other components... as a consequence I ended up in a tuner’s joint to get my ride "tuned".
Since the car comes with low impedance 440cc injectors I've upgraded it to Evo8 550cc injectors with a resistor box.
So far when I look at the fuel trim, o2 feedback they don't seem to be quite good, and I also noticed that the tuner has scale the injectors at 720!!! and also messed around with the voltage.
So far I've made the following test, logging while on idle and pumping the gas pedal a bit using 3 different setups.
Tuner setup
Evo 8 stock injector voltage and scaling
Evo 8 scaling with current (tuner) voltage setting
Appreciate if you could look at the logs and tell me which is the one you consider the most desirable.
Another question that so far I have not been able to find the answer is on whether I need to make any changes on the voltage since I have a resistor box in between (due to the impedance changes).
Thanks in advance,
Lucas
I've recently got into the Ecuflash scene... I own an Mitsubishi Airtrek, a JDM SUV with an Evo 7 engine and INVEC II sequential gearbox.
I recently upgraded the turbo, injectors fuel pump and some other components... as a consequence I ended up in a tuner’s joint to get my ride "tuned".
Since the car comes with low impedance 440cc injectors I've upgraded it to Evo8 550cc injectors with a resistor box.
So far when I look at the fuel trim, o2 feedback they don't seem to be quite good, and I also noticed that the tuner has scale the injectors at 720!!! and also messed around with the voltage.
So far I've made the following test, logging while on idle and pumping the gas pedal a bit using 3 different setups.
Tuner setup
Evo 8 stock injector voltage and scaling
Evo 8 scaling with current (tuner) voltage setting
Appreciate if you could look at the logs and tell me which is the one you consider the most desirable.
Another question that so far I have not been able to find the answer is on whether I need to make any changes on the voltage since I have a resistor box in between (due to the impedance changes).
Thanks in advance,
Lucas
#2
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These logs look like they were done right after flashing or resetting the ECU, as all LTFTs are at 0.
You have to idle the car for a good 10-15 minutes, or until the STFT (O2 feedback) is bouncing around 0. Then you have to do a steady cruise around 3000 RPM or so for a good 10-15 minutes, or until the STFT is bouncing around 0.
This will establish what your LTFT Lo and LTFT Mid truly are. Only then can someone help you here with your scaling and latencies.
Eric
You have to idle the car for a good 10-15 minutes, or until the STFT (O2 feedback) is bouncing around 0. Then you have to do a steady cruise around 3000 RPM or so for a good 10-15 minutes, or until the STFT is bouncing around 0.
This will establish what your LTFT Lo and LTFT Mid truly are. Only then can someone help you here with your scaling and latencies.
Eric
Last edited by l2r99gst; Jan 29, 2008 at 04:13 PM.
#4
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These logs look like they were done right after flashing or resetting the ECU, as all LTFTs are at 0.
You have to idle the car for a good 10-15 minutes, or until the STFT (O2 feedback) is bouncing around 0. Then you have to do a strady cruise around 3000 RPM or so for a good 10-15 minutes, or until the STFT is bouncing around 0.
This will establish what your LTFT Lo and LTFT Mid truly are. Only then can someone help you here with your scaling and latencies.
Eric
You have to idle the car for a good 10-15 minutes, or until the STFT (O2 feedback) is bouncing around 0. Then you have to do a strady cruise around 3000 RPM or so for a good 10-15 minutes, or until the STFT is bouncing around 0.
This will establish what your LTFT Lo and LTFT Mid truly are. Only then can someone help you here with your scaling and latencies.
Eric
Yep, its not a very fun process. Theres a whole thread dedicated to Injector Scaling. You'll pretty much find every answer you need in there.
https://www.evolutionm.net/forums/sh...jector+scaling
Cheers!
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Plus during the 15-20 minute process there is alot of overshoot involved, the ecu will correct, which may be +10% then during the next correction bring it down -15% but it takes a few cycles for the ecu to settle at a value, I scaled my injectors and it was a several eveing after work process until perfect but Im very specific with my car. My LTF T hover at 0 to -.78%.
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Thanks to all, I did read the post but I was looking at the short term FT rather than the long term....
Hence the post referring to the O2 feedback... which if you compare it shows some differences between them.
Anyway will try the 15 minute process uch:
Thanks for the replies!
Hence the post referring to the O2 feedback... which if you compare it shows some differences between them.
Anyway will try the 15 minute process uch:
Thanks for the replies!
Last edited by Tuky; Feb 4, 2008 at 06:12 AM.
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ok so I did the 15 minutes test on idle... and here are the results. Tomorrow I'll be doing the cruise test.
The LTFT Low and LTFT Mid are the same, no changes at all, however the O2 feedback does change...
Setting (A) gives me an oscilation between 140-160 while the otherone (B) is between 110-90... From my understanding from the Evoscan the closer you are to 100 is the better.
As for Injector latency setting (A) stays between 32-33, while setting (B) stays between 20-21.
Based on my limited knowledge setting B seems to be more suitable based on the O2 feedback, as per the latency I'm not quite sure.
Appreciate your thoughts.
Regards,
The LTFT Low and LTFT Mid are the same, no changes at all, however the O2 feedback does change...
Setting (A) gives me an oscilation between 140-160 while the otherone (B) is between 110-90... From my understanding from the Evoscan the closer you are to 100 is the better.
As for Injector latency setting (A) stays between 32-33, while setting (B) stays between 20-21.
Based on my limited knowledge setting B seems to be more suitable based on the O2 feedback, as per the latency I'm not quite sure.
Appreciate your thoughts.
Regards,
Last edited by Tuky; Feb 4, 2008 at 06:13 AM.
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