MAF Calibration Tutorial

[ms3blackmica]

This thread is a bit old now.

I think that it needs some updating for a more appropriate technique.

I made this thread to help people who were just beginning, hence it's super elementary form.

However, it seems that more and more people jump right into this at a more experienced level now.

I think that I will re-do the videos for a more integrated lesson.

[jcolton]

Thank you a ton for this man, very much appreciated!! I learned a ton, and got pointed in the right direction!

[slowspeed6]

I just did my closed loop maf log on my mazdaspeed 6 and I'm confused with the LTFT numbers I am seeing, they look nothing like the numbers in the video. I drove the car 65 miles before I did the data log. I just wanted to see if somebody could take a look at my log to make sure it would be ok to start doing the maf cal. I had a hard time even getting close to redline before I reached 100 grams per second and I was being very light on the throttle. I bought the car with a magnaflow cat back exhaust and a bov but I plan on switching to a bpv as soon as I can. I am using the Cobb ots 93 octane stage 1 map. Thanks ms3blackmica for making the tutorial, I would be lost without people like you taking the time to do these tutorials.

[Ozynigma]

Originally Posted by slowspeed6 I just did my closed loop maf log on my mazdaspeed 6 and I'm confused with the LTFT numbers I am seeing, they look nothing like the numbers in the video. I drove the car 65 miles before I did the data log. I just wanted to see if somebody could take a look at my log to make sure it would be ok to start doing the maf cal. I had a hard time even getting close to redline before I reached 100 grams per second and I was being very light on the throttle. I bought the car with a magnaflow cat back exhaust and a bov but I plan on switching to a bpv as soon as I can. I am using the Cobb ots 93 octane stage 1 map. Thanks ms3blackmica for making the tutorial, I would be lost without people like you taking the time to do these tutorials.

You only got MAF up to 120.

Up to that point your LTFT's were all less than 10% so looking good.

Try logging again, going up a gear for more air flow.

[Atticaz]

You have an aftermarket intake? If you still have a stock intake, the MAF cal is not needed. Your fuel trims look great, as stated above.


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[Vansquish]

Originally Posted by slowspeed6 I just did my closed loop maf log on my mazdaspeed 6 and I'm confused with the LTFT numbers I am seeing, they look nothing like the numbers in the video. I drove the car 65 miles before I did the data log. I just wanted to see if somebody could take a look at my log to make sure it would be ok to start doing the maf cal. I had a hard time even getting close to redline before I reached 100 grams per second and I was being very light on the throttle. I bought the car with a magnaflow cat back exhaust and a bov but I plan on switching to a bpv as soon as I can. I am using the Cobb ots 93 octane stage 1 map. Thanks ms3blackmica for making the tutorial, I would be lost without people like you taking the time to do these tutorials.

You need to check the Open Loop/Closed Loop (OL/CL) transition loads for the map you're using, and try and stay out of OL. It's likely that everywhere you're seeing -0.16, you're slipping into OL, and the result is that your attempt to MAF calibrate is not going to provide you with a great deal of useful information.

To that end, you should also log "calculated load" so that you can ensure that you're not slipping into OL by accident.

You may also wish to check your LTFT breakpoints to make sure that you understand where transitions between calibration regions are occurring.

[slowspeed6]

Yes I still have the stock intake. I just thought i needed to do the maf cal after installing the map. I'm actually a little relieved I don't have to tackle the maf cal just yet lol. I'm still new and have a lot to learn. Thanks for the help guys.

[Atticaz]

Oh. I see. My bad. Brain fart. You are right. Long day at work.


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[Atticaz]

I was told by Justin from FREEKTUNE that you are fine in 2nd gear, 1500 to 6000 and just stay out of boost the whole time. He's got my shit on lockdown.


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[slowspeed6]

Originally Posted by Vansquish You need to check the Open Loop/Closed Loop (OL/CL) transition loads for the map you're using, and try and stay out of OL. It's likely that everywhere you're seeing -0.16, you're slipping into OL, and the result is that your attempt to MAF calibrate is not going to provide you with a great deal of useful information. To that end, you should also log "calculated load" so that you can ensure that you're not slipping into OL by accident. You may also wish to check your LTFT breakpoints to make sure that you understand where transitions between calibration regions are occurring.

I looked at accesstuner and couldn't find the Open Loop/Closed Loop transition loads. What section should I look at to find it? I thought -0.16 meant it was open loop from watching the video but I just didn't know if it was possible in lower rpms. Is there anything I can change in my driving to stay out of open loop? I also didn't change any of the LTFT breakpoints like was done in the video. I wasn't sure if I should because he said they were set to his driving style. Should I do that and if I do will the LTFT have to be re learned?

[Vansquish]

To answer your questions in order:

1. The tables are called, "Closed Loop Max Load [A-D]," and are in the Closed Loop Tables section of ATR.

2. Open loop is possible in any gear, and in neutral, and at pretty much any RPM as well. It all has to do with what loads/throttle angles are allowed before the OL threshold is achieved.

3. Yes. You need to be even slower accelerating, and do it on as smooth, flat, and open a stretch of road as possible.

4. You don't need to change the LTFT breakpoints (necessarily), but you should know where they are so that you know what data to plug in and whether your car is functioning normally.

5. Every time you flash a map, the ECU has to relearn fuel trims, and in my experience, the MS6's LTFTs don't really settle until over 100 miles.

IMHO, you don't really need to try and get all the way to 120g/s or whatever that last breakpoint is. It will help the car give a more accurate reading for whatever the last section of the CL calibration encompasses, but the likelihood is that if you're over 80g/s during normal driving circumstances, you're over 1.0 Load, and probably in OL anyway.

[slowspeed6]

Originally Posted by Atticaz I was told by Justin from FREEKTUNE that you are fine in 2nd gear, 1500 to 6000 and just stay out of boost the whole time. He's got my shit on lockdown. Sent from my iPhone using Tapatalk

So he said I'm fine without the maf cal for right now? Should I do logs in other gears to check them? I did a WOT log in 4th gear from 3,000 rpms to redline and saw 3.14 KR at 3,400 rpms. I'm going to try and figure out why before going WOT again. Thank you for the help and I think I'm going to go with freektune also once I get full bolt ons.

[Atticaz]

Originally Posted by slowspeed6 So he said I'm fine without the maf cal for right now? Should I do logs in other gears to check them? I did a WOT log in 4th gear from 3,000 rpms to redline and saw 3.14 KR at 3,400 rpms. I'm going to try and figure out why before going WOT again. Thank you for the help and I think I'm going to go with freektune also once I get full bolt ons.

No. I was just conveying how he told me to do my logs for my MAF cal, is all.

Before I got a tune. I used an OTS and did my MAF cal this way. I was dead on perfect with the cut and paste MAF values Corksport sent me. I didn't know they had ones to use back when was super n00b. Lol

I did mine in 2nd gear 1500-6000 and followed the videos initially.

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[slowspeed6]

Originally Posted by Vansquish To answer your questions in order: 1. The tables are called, "Closed Loop Max Load [A-D]," and are in the Closed Loop Tables section of ATR. 2. Open loop is possible in any gear, and in neutral, and at pretty much any RPM as well. It all has to do with what loads/throttle angles are allowed before the OL threshold is achieved. 3. Yes. You need to be even slower accelerating, and do it on as smooth, flat, and open a stretch of road as possible. 4. You don't need to change the LTFT breakpoints (necessarily), but you should know where they are so that you know what data to plug in and whether your car is functioning normally. 5. Every time you flash a map, the ECU has to relearn fuel trims, and in my experience, the MS6's LTFTs don't really settle until over 100 miles. IMHO, you don't really need to try and get all the way to 120g/s or whatever that last breakpoint is. It will help the car give a more accurate reading for whatever the last section of the CL calibration encompasses, but the likelihood is that if you're over 80g/s during normal driving circumstances, you're over 1.0 Load, and probably in OL anyway.

Thank you for all of your help. I hate to ask a ton of question but this stuff is still like another language to me. I have to go out of town for work but when I get back I will get over 100 miles on this map and try to stay out of open loop while doing the log.

[udntknw]

Originally Posted by slowspeed6 Yes I still have the stock intake. I just thought i needed to do the maf cal after installing the map. I'm actually a little relieved I don't have to tackle the maf cal just yet lol. I'm still new and have a lot to learn. Thanks for the help guys.

Honestly for me, doing the MAF cal really taught me the basics of logging, understanding logs, making changes in ATR, etc. Once I got comfortable doing the MAF cal and manipulating ATR, it made the rest of the running process more comfortable.

[BAT-man]

Necrooo....

Does anyone know what "MAP Scalar for EM/OBD - Component A/B" and the offset parameters do?

[3toedSloth]

I know this is a super old thread but are these videos still available someplace or can be re-uploaded and linked? I'm in the process of figuring out how to MAF tune.

[joey]

Hi guys, can someone please help me? I'm having an issue with a buddy's MS6 where the MAF goes tits up around 1.7-2.2v MAF volts. The MAF cal is abs(6).

Mod list:

Built motor
Corksport cams
Corksport Intake mani
Corksport TB
Big Turbo
3" Turboback exhaust
HPFP Upgrade
3.5" HTP intake
VTCS delete


CL log

[joey]

Originally Posted by joey Hi guys, can someone please help me? I'm having an issue with a buddy's MS6 where the MAF goes tits up around 1.7-2.2v MAF volts. The MAF cal is abs(6). Mod list: Built motor Corksport cams Corksport Intake mani Corksport TB Big Turbo 3" Turboback exhaust HPFP Upgrade 3.5" HTP intake VTCS delete CL log

Anyone?

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[Vansquish]

@joey;

At first blush, I was pretty convinced that a sensor was dying or in need of cleaning, and this may still be the case. (Note that I said, "a sensor," not "the MAF sensor.")

Here are a couple of other thoughts that occurred to me.

The MAF voltage trace looks pretty damn smooth. It gradually increases from about 1.57V where the calibration run really starts, and 3.04V where the run ends. Between about 1.7 and 2.02V, something is happening to your calculated AFRs though.

It could be a bad MAF calibration in conjunction with the larger-than-stock throttle body. If the throttle body or MAF housing are causing some turbulence that alters MAF sensor readings between about 1.7 and 2.02V, that could be part of the problem. This seems a bit unlikely, unless the MAF housing doesn't have an air-straightener in it.

The fluctuations that you are seeing in the data look a bit like the ECU is trying to compensate for something (wild fluctuations between two values making a sawtooth waveform). To me, because the MAF voltage trace is nice and smooth, I'm inclined to think that you actually have a problem with one of your O2 sensors.

This theory is supported by a couple of things.
1) Your MAF voltage trace is smooth and increases over the rev range (it would be better if in the future you would include the MAF g/s trace as well).

2) Your STFT readings are categorically not smooth anywhere in the graph. This sort of suggests that the baseline MAF calibration isn't very good, or, as is likely the case here, you have one or more bad O2 sensors.

3) This calibration log should've been in closed loop the whole time. However, you may notice that the LTFTs register a solid -0.16 for the entirety of the log. This could be a sign of at least two things:
a) There aren't enough miles on this map for the LTFTs to have been calculated and used by the ECU, and/or
b) The car is stuck in open loop.

If the car is stuck in open loop, then the most likely reason for that is a failed primary O2 sensor.

[joey]

Originally Posted by Vansquish @joey; At first blush, I was pretty convinced that a sensor was dying or in need of cleaning, and this may still be the case. (Note that I said, "a sensor," not "the MAF sensor.") Here are a couple of other thoughts that occurred to me. The MAF voltage trace looks pretty damn smooth. It gradually increases from about 1.57V where the calibration run really starts, and 3.04V where the run ends. Between about 1.7 and 2.02V, something is happening to your calculated AFRs though. It could be a bad MAF calibration in conjunction with the larger-than-stock throttle body. If the throttle body or MAF housing are causing some turbulence that alters MAF sensor readings between about 1.7 and 2.02V, that could be part of the problem. This seems a bit unlikely, unless the MAF housing doesn't have an air-straightener in it. The fluctuations that you are seeing in the data look a bit like the ECU is trying to compensate for something (wild fluctuations between two values making a sawtooth waveform). To me, because the MAF voltage trace is nice and smooth, I'm inclined to think that you actually have a problem with one of your O2 sensors. This theory is supported by a couple of things. 1) Your MAF voltage trace is smooth and increases over the rev range (it would be better if in the future you would include the MAF g/s trace as well). 2) Your STFT readings are categorically not smooth anywhere in the graph. This sort of suggests that the baseline MAF calibration isn't very good, or, as is likely the case here, you have one or more bad O2 sensors. 3) This calibration log should've been in closed loop the whole time. However, you may notice that the LTFTs register a solid -0.16 for the entirety of the log. This could be a sign of at least two things: a) There aren't enough miles on this map for the LTFTs to have been calculated and used by the ECU, and/or b) The car is stuck in open loop. If the car is stuck in open loop, then the most likely reason for that is a failed primary O2 sensor.

Thanks for the comprehensive reply. We were in the process of calibrating the MAF since the new motor build, so its not done yet. This is where I noticed the problem.

What I have tried:

Tripple cleaned sensors, like MAF & primary O2 sensor etc;
Back to stock TB made no diff;
Replaced purge valve;
Smoke test for potential leaks.

The HTP intake has a air-straightner. Also tried different MAF cals in the lower volts region made no noticable difference. The wild spikes still occur(1.7-2.2v). The car is definitely in CL. Next time I will add the CL** monitor to the list of monitors. When doing OL logs the car does hit its targets, but for daily drivabilty the affected volts range get hit quite offen and makes the drive horrid.

We have ordered the new O2 sensors as this is the last thing on the list that we have overlooked. Never thought of the O2's to be the issue as they read fine in the rest of the ranges and the ECU never complained about them, but if this was the cause I will be stumped. ALSO very relieved.

PS: The MAF g/s is included in the datazap logs. I know you said you took a quick look at the logs, so no biggy.

**Closed Loop - Closed/open loop fuel system status.
256 = During decel (fuel has resumed)
512 = normal closed loop operation
1024 = Open loop (also reported when engine off, during decel while no injection is occurring)

[Vansquish]

Originally Posted by joey Thanks for the comprehensive reply. We were in the process of calibrating the MAF since the new motor build, so its not done yet. This is where I noticed the problem. What I have tried: Tripple cleaned sensors, like MAF & primary O2 sensor etc; Back to stock TB made no diff; Replaced purge valve; Smoke test for potential leaks. The HTP intake has a air-straightner. Also tried different MAF cals in the lower volts region made no noticable difference. The wild spikes still occur(1.7-2.2v). The car is definitely in CL. Next time I will add the CL** monitor to the list of monitors. When doing OL logs the car does hit its targets, but for daily drivabilty the affected volts range get hit quite offen and makes the drive horrid. We have ordered the new O2 sensors as this is the last thing on the list that we have overlooked. Never thought of the O2's to be the issue as they read fine in the rest of the ranges and the ECU never complained about them, but if this was the cause I will be stumped. ALSO very relieved. PS: The MAF g/s is included in the datazap logs. I know you said you took a quick look at the logs, so no biggy. **Closed Loop - Closed/open loop fuel system status. 256 = During decel (fuel has resumed) 512 = normal closed loop operation 1024 = Open loop (also reported when engine off, during decel while no injection is occurring)

Thanks for the response, and my apologies for not noticing the MAF g/s. I hadn't used datazap before, and missed that parameter.

As for the discussion of the closed/open loop fuel (CL/OL) system status, if there aren't enough miles (or more accurately, enough time to calibrate each of the MAF CL breakpoints) on the tune, the MS6 ECU runs in OL, even though it may not show up as such directly in the logs.

As a further measure of troubleshooting, you might want to try swapping in a known good MAF sensor and running the same test cycles.