Clarification on Coyote MAF tuning

[txcharlie]

I feel like I take 1 step forward and 2 steps back. Every time I think I understand something about tuning my car, something happens that goes against what I thought I knew.

Can someone give me a good, reliable method for tuning the MAF on the coyote? I've been using STFT as a correction factor and it doesn't seem consistent enough. I have LTFT learning disabled and zeroed out the temp compensation table while logging.

My problem is, I have 3 different drive logs and each one shows lean or rich conditions differently. Log1 showed lean condition of 1.04 in period 187.1. Log2 showed the same period as .98 rich condition and log3 showed the same period as perfect at 1. Is this normal?

These are 6,3, and 9 minutes logs. Are the logs too short to get a good sampling?

I've read about the ABC method to correct the MAF. Is that more reliable?

[toyoguru]

I feel like I take 1 step forward and 2 steps back. Every time I think I understand something about tuning my car, something happens that goes against what I thought I knew.

Can someone give me a good, reliable method for tuning the MAF on the coyote? I've been using STFT as a correction factor and it doesn't seem consistent enough. I have LTFT learning disabled and zeroed out the temp compensation table while logging.

My problem is, I have 3 different drive logs and each one shows lean or rich conditions differently. Log1 showed lean condition of 1.04 in period 187.1. Log2 showed the same period as .98 rich condition and log3 showed the same period as perfect at 1. Is this normal?

These are 6,3, and 9 minutes logs. Are the logs too short to get a good sampling?

I've read about the ABC method to correct the MAF. Is that more reliable?

With MAF tuning, make sure you are filtering the cells so nothing shows up below a certain hit count, I would go with somewhere around 50, and see how the average goes then. Also, are you using just one bank, or doing a custom PID giving an average between both banks?

[txcharlie]

Thanks Guru! I was only using bank 1 STFT and sampling a minimum of 10 hits. I will create the custom PID and do some more logs. It didn't cross my mind that I was only using 1 bank to get my average.
I'm not sure if it makes a difference but I'm on e85. I was about to run a tank of 93 anyway, so I will see if it's more consistent with it.

[David Borden]

Are you using 2.4 or 2.5 scanner? I recently read stft were to quick to be useful and one should use ltft as well. ??

[AKDMB]

I'm a complete noob and will probably be tuning a coyote here in a few months, I have seen some apply their correction factor to the MAF transfer function by using multiply % - half, any reason for this? Also what all needs to be turned off to make sure the car doesn't try to learn and apply changes during the MAF tuning process? My new MAF housing will only be 3mm larger than stock so how far off will the car be?

[txcharlie]

Are you using 2.4 or 2.5 scanner? I recently read stft were to quick to be useful and one should use ltft as well. ??

Not using HPT scanner, as I can't get histograms to work in 2.25.

[txcharlie]

I'm a complete noob and will probably be tuning a coyote here in a few months, I have seen some apply their correction factor to the MAF transfer function by using multiply % - half, any reason for this? Also what all needs to be turned off to make sure the car doesn't try to learn and apply changes during the MAF tuning process? My new MAF housing will only be 3mm larger than stock so how far off will the car be?

I'm a noob too, but as far as I know there are 2 ways to tune the coyote MAF. The easiest way is to use STFT as your correction factor. As stated above, use the average of Bank 1 and 2. Another way is the ABC method....Actual By Commanded. You take your logged AFR(avg of both banks) and divide by commanded lambda. I've only used the STFT method because I'm lazy. LOL! I don't know which is supposed to be more accurate.

You need to disable LTFT learning and zero out the temp compensation table while logging.

[AKDMB]

What is the true definition of STFT then? I thought it was already Actual/Commanded. I think I might be confused.

[bluegoat06]

I used LTFT's, actual vs commanded error, but applying half of the error everytime, For whatever reason in my car, it take at least 40-50 miles (hwy) for the LTFt's to be useful in my logs, what I mean by that is that my car seem to run leaner LTFT's during this 40-50 miles, so if I'm starting with say 10% ltft's, i'll start adding a 5%-6% to the period table , drive for 40-50 miles, then I can start adjusting my period table based on the info I get from my LTFT's, trying to reach a -2%+2% in the end. if I try to do this after the 1st flash, without driving those 40-50 miles first, i'll end up overshooting my fueling, typically over the rich side. don't know why it does this, but now I can get consistency in my fueling.

[txcharlie]

What is the true definition of STFT then? I thought it was already Actual/Commanded. I think I might be confused.

This applies to copperhead pcm....If you have .9 STFT, it means the pcm is pulling ~10% because it's running rich. A 1.1 STFT would mean it's adding ~10% fuel because it's running lean.

Most of the stuff you read about in books and see on videos, doesn't apply to the coyote. With copperhead pcm your STFT is the correction factor.

[txcharlie]

I used LTFT's, actual vs commanded error, but applying half of the error everytime, For whatever reason in my car, it take at least 40-50 miles (hwy) for the LTFt's to be useful in my logs, what I mean by that is that my car seem to run leaner LTFT's during this 40-50 miles, so if I'm starting with say 10% ltft's, i'll start adding a 5%-6% to the period table , drive for 40-50 miles, then I can start adjusting my period table based on the info I get from my LTFT's, trying to reach a -2%+2% in the end. if I try to do this after the 1st flash, without driving those 40-50 miles first, i'll end up overshooting my fueling, typically over the rich side. don't know why it does this, but now I can get consistency in my fueling.

I thought LTFTs should be turned off to tune the MAF.

[AKDMB]

I'm curious, I will only be making the MAF housing 3mm larger (packaging reasons), how far off will my calibration be, if any?

[txcharlie]

I'm curious, I will only be making the MAF housing 3mm larger (packaging reasons), how far off will my calibration be, if any?

Stock tube is 86mm which has an area of 5809. 89mm has an area of 6221. 1/(5809/6221)= 1.07. You would multiply your MAF Airflow vs Period by 1.07 to get you close and then fine tune with logging.

[David Borden]

I'm curious, I will only be making the MAF housing 3mm larger (packaging reasons), how far off will my calibration be, if any?

For what its worth, mine is the same diameter as stock but aluminum vs plastic using a cone air filter and it appears over 20% off at the lower side of the flow range and ~5-10% up high in the range based on fuel trim readings from scanning... I would make no assumptions.



David

[txcharlie]

For what its worth, mine is the same diameter as stock but aluminum vs plastic using a cone air filter and it appears over 20% off at the lower side of the flow range and ~5-10% up high in the range based on fuel trim readings from scanning... I would make no assumptions.



David

Desired setup for MAF placement is to have a section of straight pipe before and after the MAF that is equal to 2X the diameter. Looks like you may be a little close to the end.

[SultanHassanMasTuning]

if you have your car drivable and running ok, i would re-enable the LTFT and get your maf dialed in that way. STFT change too much and too fast. now you will still need to keep your eye on your STFT at full throttle to hit your target.

[txcharlie]

Everything I've read said to disable LTFTs when tuning the MAF, but it seems several people on here use them and are getting good results. What's the best way to use LTFTs to dial in the MAF?

[caniggia]

Best is to create custom pid that will make stft+ltft and you don't need to disable anything.

[SultanHassanMasTuning]

once you get your LTFT, after depends on the temp thresh that activates LTFT, and dial in your maf that way. best on the dyno so you can hit all maf periods/Hz accurately and finalize your maf curve

[txcharlie]

Can someone explain the method for using LTFT to tune the MAF? On the coyote, I only know how to use STFT and ABC method to tune MAF.