Questions regarding the MAF and tuning

1. My MAF (and T/B) is about 2.5% bigger than stock.
a) What do I have to adjust in my tune to optimize things?
b) Should I raise my airflow in "MAF Calibration: Airflow vs. Frequency" by 2.5% all across the table?

2. I want to do a LTFT tune and I have to disable the MAF first.
a) If I tune it with the MAF disabled and get everything spot on, then what happens to my tune AFTER I enable the MAF again? Do values get messed up or does it (make no difference) just make it easier on the PCM (like a 2nd data input) by using both MAF and VE readings?
b) I can just disconnect my MAF plug instead of messing with my MAF settings/tune, correct? My IAT sensor isn't part of my MAF.

3. Where is "MAF File High" and/or "MAF Sensor Fail Frequency" in the Editor anyways (as mentioned in 2 tuning instructions)? All I have is "Airflow vs. Frequency" under "MAF Calibration". Is it the same thing and what-was listed in previous Editor versions?

1.
A. You'd just have to do MAF tuning to correct for the small change in TB size.
B. No need to just add 2.5% worth a fuel everywhere, that wouldn't be helping you right off the bat.

2.
A. The values don't get messed up but you'd want to tune the other half (that being the MAF) after you tune the VVE. You would disable the VE and tune the MAF sensor, then onces both are done you can revert back to mixed mode and have both tuned correctly. There may be minor adjustments needed after you are done with both. You can tune both the VE and MAF with LTFT outside of WOT just fine.
B. It's easier to just setup the tune for speed density instead of disconnecting it.

3. Open Engine Diag in the editor. That is where your airflow table and DTC's page are. You'd set the high disable to 0hz and the 3 MAF dtc's to fail on first error to put it into speed density.

Thanks for your help and quick reply, 5FDP.

Damn I was hoping I could just add 2.5% somewhere.. instead of recording more drives, doing MAF (and whatever other) tuning, breaking my balls...
Hmm so if I increased the MAF table/cells, I'd be adding more fuel..... Something tells me I should just increase the table/cells a bit, right off the bat since I'm running lean part throttle + have a bigger intake system.
Even in the MAF Calibration area it says "If you modify your MAF meter you will likely have to modify this table".
More reason for me to want to just modify the table and be done with it..

Frustrated rant time..
I feel like everyone makes this way more complicated than it is and way more time consuming. Like why couldn't I just raise my MAF settings a touch since I know my intake system is a bit bigger than stock + can also see that I'm running lean at part throttle.. then record a drive and see if it made an improvement or if I overshot it :confused:
This disabling-this-to-enter-this-mode-then-adjust-this-and-check-that-then-relearn-this-with-a-50-minute-drive...business is ridiculous. I'll do it.. but only if I'm 100% convinced that it's neccessary.
I just see it as: I can see that I'm running lean at part throttle, know where/when I'm running lean, so I should simply add a bit of fuel there to richen it up.. without doing a hundred other things. One table, edit the numbers, drive, check, adjust, drive, check, done.

And how is adjusting MAF settings and checking DTCs and making sure it's in SD... easier (for me) than unplugging a little electrical connector in a very easy to-get-to spot :confused: Unplugging my MAF takes me around 3 seconds. Disabling my MAF via HPT will take me maybe 10 minutes, give me a headache trying to make sense of everything and make sure I'm doing/editing the right thing and I probably still wouldn't be sure that it's disabled in the end. I don't understand the DTC page.. when there's a code, when there isn't, what Error Mode + SES Enable + ticks mean.... it's all Chinese to me.

Go ahead and do what you want, I'm just offering my advice on how I tune. If you think adding to the MAF curve will fix it, do it and see what happens. It may or may not do the trick and it's still possible to overshoot it a little. In the end it could take the you same amount of time if you have to make the tune, flash it, go for a drive, make another change, go for a drive, see what it's like and so on. Either way "could" work I guess.

I feel the way I do it adds no extra time to tuning and however long it takes it however long it takes me to tune. It's just part of the game.

You could easily fix the MAF curve all the way through for the most part in two 15 min logs with steady driving and normal throttle movements.

DTC"s are easy to understand. First error means it will trip the SES light the first time a fault is seen, if the code is set to 2nd error it will trip the SES when the computer see's the same fault twice in a drive cycle or perhaps once in several drive cycles. 3rd error/no report will never show a SES light. The reason to set the MAF dtc's for speed density is so that it knows that the MAF has failed right away and reverts to speed density. (another reason for setting the MAF fail high to 0hz because that lower than the computer would ever see and trip the error code)

Quote:

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Originally Posted by Mr. Smith

Thanks for your help and quick reply, 5FDP.

Damn I was hoping I could just add 2.5% somewhere.. instead of recording more drives, doing MAF (and whatever other) tuning, breaking my balls...
Hmm so if I increased the MAF table/cells, I'd be adding more fuel..... Something tells me I should just increase the table/cells a bit, right off the bat since I'm running lean part throttle + have a bigger intake system.
Even in the MAF Calibration area it says "If you modify your MAF meter you will likely have to modify this table".
More reason for me to want to just modify the table and be done with it..

Frustrated rant time..
I feel like everyone makes this way more complicated than it is and way more time consuming. Like why couldn't I just raise my MAF settings a touch since I know my intake system is a bit bigger than stock + can also see that I'm running lean at part throttle.. then record a drive and see if it made an improvement or if I overshot it :confused:
This disabling-this-to-enter-this-mode-then-adjust-this-and-check-that-then-relearn-this-with-a-50-minute-drive...business is ridiculous. I'll do it.. but only if I'm 100% convinced that it's neccessary.
I just see it as: I can see that I'm running lean at part throttle, know where/when I'm running lean, so I should simply add a bit of fuel there to richen it up.. without doing a hundred other things. One table, edit the numbers, drive, check, adjust, drive, check, done.

And how is adjusting MAF settings and checking DTCs and making sure it's in SD... easier (for me) than unplugging a little electrical connector in a very easy to-get-to spot :confused: Unplugging my MAF takes me around 3 seconds. Disabling my MAF via HPT will take me maybe 10 minutes, give me a headache trying to make sense of everything and make sure I'm doing/editing the right thing and I probably still wouldn't be sure that it's disabled in the end. I don't understand the DTC page.. when there's a code, when there isn't, what Error Mode + SES Enable + ticks mean.... it's all Chinese to me.

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Because sir, that connector also contains 2 wires for you Intake Air Temp sensor (unless you have relocated it) which when disconnected, will report -40 degrees all the time. That will F up all your fueling calculations.

There are more than one way to tune a vehicle but only one way to do it right....You sir sound like we all make it more complicated than it is and several really good calibrators have supported us by writting books and generating DVD's to perpetuate this scam. The gentlemen was just trying to help you with conventional wisdom.

Ed M

Thanks for your time and help again. I appreciate it.

Quote:

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Originally Posted by 5FDP

I feel the way I do it adds no extra time to tuning and however long it takes it however long it takes me to tune. It's just part of the game.

You could easily fix the MAF curve all the way through for the most part in two 15 min logs with steady driving and normal throttle movements.

DTC"s are easy to understand.

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You forget though.. I am not you. I am not an experienced tuner. Nothing here is easy for me to fix or understand. It all involves a lot of reading, learning, time, stress... for me. Something might not take you extra time, but will take me a tonne of extra time.
You "have to" put yourself in my shoes. Think from a beginners point of view.
I still don't understand the DTC page after you explained it to me and reading your post 20x. I understand the left hand side area (codes + descriptions) easily, but have no idea what's up on the right hand side. It's not clear. At all. And it doesn't offer any tips/help when you go over it with the cursor like it does with everything else in VCM Editor.
(You don't have to explain it to me again/further. I'll try to figure it out.. some day)

I'm going to edit the MAF table a bit, see what difference it makes to my LTFTs and everything else. If it gets worse, I'll just adjust the MAF numbers the other way and if that fails, go back to how it was and tune everything the right/long way.


@mowton: As I mentioned in "2. b)", my IAT isn't part of my MAF.. and I wasn't being rude to 5FDP. I'm just frustrated at how overly complicated and involved this e.tuning is. You'd think it would be something like "Add fuel to richen mixture. The end", instead it's "disable this unrelated thing, increase air (in one of the sixty air-related tables) to fool the computer, set DTCs for this, ~half an hour later~, copy this table to that, reset this, relearn that, drive to another state, pull over and stand on your head while drinking a cup of coffee........".

Quote:

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Originally Posted by StopGap

I think I've spent more hours over the last ten days and have read more about tuning with HP tuners than I did getting my Engineering Degree.

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We have all been in your shoes and we all had to read and re-read and re-read instructions. Most of us remember those days. It is because of that that these guys write to help new tuners learn and to try to keep them from making the same mistakes. While a lot of it is trial and error (like MAF)...mistakes in some areas can cost you big.

These guys who took the time to help you help literally every newbie that comes through the door with the same questions over and over. They are awesome and everybody on here knows it.

Good luck

Focused time =knowledge. trial and error as some would say goes a long way. I was overwhelmed at first but once i started slowing down And trying to thoroughly read the definitions. and read around the forums it becomes understandable In time. By no means do I consider myself a knowlegleable tuner but in time I have to created a system that works well for me. key word TIME! If you don't have time you probably don't have patience, which is two things you most certainly need to learn anything in life.

Mowton's Guide is well worth the money. He provides explanations as to why to do all the little things rather than just saying change this and change that. When you understand how everything works together the things that seem unrelated now will make more sense.

Thanks guys. I know I'll get there... slowly understand/master everything.... but I still think this is way too complicated (and time consuming) for the average car enthusiast.. no no - advanced car-modifier.. and needs to be made more simple. It's just not worth it. It's like choosing to drive from California to New York instead of flying there because you thought it'll save you $100 (buying tuning software + tuning yourself vs. paying pro tuner to tune your car).
Like now I feel I'm stuck with spending at least an hour of my time every day for the next 5-12 years, reading and learning about every tuning table... I'm probably spending/averaging 3+ hours a day reading all things HPT. I knew it would be bad, but not this bad.

Anyway,
I x'ed my MAF frequency table by 1.02
I didn't really notice a difference.
After going over several sample MAF tunes, I see that they are pretty custom.. not linear.. some have a higher frequency up high (compared to another car) but lower down low.

Looks like I'll have to tune my MAF the proper way since I have a custom intake system.

MAF physical size and MAF calibration (Hz/(g/sec)) are
not related other than by whatever's in the electronics.
What you want is a manufacturer's calibration curve.
Which for Delphi standard parts resides in tune files for
the cars that used the piece (with some, sometimes
significant) variations platform-platform).

If you bought an aftermarket "performance" piece, then
go ask the manufacturer for their cal data. If you enjoy
the sound of dismissive chuckling.

2.5% difference is within the realm of manufacturing slop.
If that is electrical signature, anyway. I've been told that
the MAF is about a 5% tolerance piece by a lab that had
tested a bunch. So even picking up a blessed cal table
can't be counted on to get you dead-nuts airflow accurate.

But I bet you don't know fuel pressure or true injector
delivery at ideal pressure to any better accuracy either.
So don't overthink it.