hey guys would greatly appreciate any help. I'm trying to calibrate my MAF and getting positive numbers especially in the lower hrtz range. I was under the impression they should be negative -0-2 (target). how do I subtract g/cyl without over shooting. I know I can add by % but not subtract by %. I haven't seen any videos or anything in the forums about this. it is a 15 Silverado L83 stock with K@N CAI I will attach my log and tune file. I'm new to tuning and just trying to figure this thing out. Thanks
Don't have HP on this computer to see your log but your graph should be populated with AFR or EQ error %. You just copy this data and paste special/multiply by % (or 1/2%), not add or subtract.
so even if I'm getting positive numbers I still multiply by %? I would think that would make them even higher. thank you for the help man. seems nobody else is willing too. I guess I should have wrote my post better. what I mean is am logging my maff with afr error. and getting +1s and even higher. my confusions is when I paste this to my table by multiply by half % wont that make the positive numbers even higher? I have read and seen videos saying you don't want +numbers but nobody shows how to lower them just multiply% of the negative. again appreciate the help a lot man. I just cannot afford the tunning schools class right now.
A couple things, I dont want to be rude, but GEN5 is no joke.
The new trucks/cars are no easy task and that is fact. I spent months logging and making small changes to my 2017 6.2 A8 truck. This is the most convoluted mess ever. It literally took me months to get the courage up to cam and header the truck and even more courage to work with aftermarket made boost. I have been a master tech for over 20 years, custom car builder for half of that and have tuned dozens of the the GEN3 and 4 cars and trucks from stock all the way to wild. The biggest piece of advice i can give is dont take huge leaps and step into this slowly.
Do you have a wideband O2 sensor for logging? Preferably one in each bank? I believe that not having one is a huge mistake. The AEM 30-0334 is a great unit at its price point and is about the easiest thing to use, ever. I promise the expense is worth it.
When it comes to logging, the GEN5 stuff requires a ridiculous amount of channels due the true complexity of what is going on. I log just enough channels so the computer doesn't crash and the logged data stays consistent, i would say roughly 60. As I believe these are all critical to properly collecting, analyzing and applying the proper math to the proper data. The thing that you have learn how to do is build your own charts, graphs, user maths and filters to graph the data. Once the filters and maths are applied correctly you can begin to trust the copy and multiply by percent. Learn the math, trust the math and apply the math.
Long story short is that if you graph the trims math in the scanner against the MAF curve properly it is as easy as copy, paste and multiply by percent.
Here is a screen shot of what my scanner looks like
Ok I have HP on this computer. It looks like you are not logging a wideband, correct? If no wideband, you can only adjust part throttle via fuel trims in closed loop, not WOT, which is open loop. This is why you are seeing zero's around 6,000 hz and up, as it is in open loop and not considering fuel trims.
For your question on the positive numbers, when you apply them to the MAF cal you are multiplying that percentage error (in this case positive) to the airflow number, which increases the airflow number in the cal. That tells the ecm that it is flowing more air at this particular frequency than previously, and so will add more fuel at that point, which is what you want.
It looks like you only have slight positive numbers (max average cell is 5) in the lower ranges only. Remember that this data will change that much day to day. You could make no changes and run another log and it may be 0 or negative in the areas that are currently positive.
You've got a nearly stock vehicle which is perfect for learning, just don't go crazy on your changes. Research using filters for your graph data too, such as throttle changes, etc.
For driveability, take a look at the PE settings (power enrich). Engine/Fuel/Power Enrich tab. Stock, they put lots of delay in it via RPM, ECT, Enrichment Ramp-in Rate. Good for fuel economy but not so good for fun.
You sir are a godsend! Thank you for explaining it to me! Makes perfect sense. And yes you are correct. I have no WB yet. I was using LTFT STFT math for my MAF parameter. And yes the truck is completely stock other than CAI and 3in cat back flowmaster. I haven?t done any changes at all to tables or anything for that matter other than setting PE to 50%. And Speedo cal for 33s. I have been studying my butt of trying to learn as much as possible. It is my Daily so don?t want to mess anything up. From what I have read and understand sense I have put a CAI on I need to calibrate my maf due to more volume of air. Hence the post. I think I will just leave it be until I can get a WB and take the Gen V class. I have read a couple Gen 3&4 books but the new Gen V stuff is very different. Doesn?t help that the HPT version 4.2 is very different from the books and videos I am getting my info from as well! Again thank you for taking the time to break it down for me. I have been trying to find info on how to tune my VE tables as well but hard to find for Gen v. And not the same as older versions. If you?re ever in Ohio look me up I?ll buy ya dinner! Thanks again
Oh and yes I was only trying to Calibrate for lower hertz range. I think I may have posted the wrong log. It should have been idle and part throttle. IE closed loop.
Just looked at your cal and if you want to isolate the MAF you should change, under Engine/Airflow/Dynamic/Dynamic Airflow, change High RPM Disable to 400, and High RPM Reenable to 300. (stock is 4000/3900) This will put you under full MAF control instead of a blended MAF/VVE. Once the MAF is dialed in then put those figures back to stock. You could play with it at part throttle to get a feel of how to do it for now. When you get a wideband, then go back into it and dial in the full range. Regarding VVE tuning, I am still struggling a bit with it on a Gen4.
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