i am trying to figure out how to tune my maf. in sd the truck runs amazing. with maf enabled it runs like crap. not the same power. my maf curve looks like a squiggly line from the last shop that tuned it. i cant seem to download or find a good copy of the MAF!LTFT file. i have never tuned any thing before so sorry if this is a stupid question..
Any chance of you posting up log and tune files?
FLACCO FRIST SMOOTH VE TABLE v2.hpt17-05-26 19-40-29.hpl
here is the tune and a log.. not sure whats on the log though. thanks.
So the maf and ve tables need to if not match then at least very closely correlate with each other. And that is hard to do when we have skewed maps for each. You should first start with your ve table. Under the engine diagnostics tab you need to set your maf fail high to 0hz, turn off your PE, DFCO, and COT, and populate a chart of your ve table over ltft or afr error or whatever sensor / math you prefer to tune to. After you log some data and update your ve table a few times, you can manually adjust different cells in 3d view by left clicking and dragging the cell up and down. This should allow you to take your ve table from this..
To something that more closely resembles this..
Once you have a smooth ve table without any big or sudden changes from one cell to the next then you can set your maf fail high back to 13,500hz or whatever it was and under engine / airflow / dynamic / under the column for dynamic airflow you can set the High Rpm Disable to a low number, like 200rpm. This will force the ecu to use the maf sensor table. Then you can use a similar chart and process to tune the maf sensor calibration. Usually that sensor calibration will take a curve that resembles something like this..
If you can find a few known good points of calibration. You know where your fuel trim data is close to 0 or - a few then you can logically apply this curve to your calibration and at least call it a starting point. Your calibration currently has some troubles..
It would probably do you better to smooth these tables in 2d or 3d view before you start trying to log data and correct them. When there are sharp changes from one cell to the next it plays hell with trying to fetch good data. Smooth the table, try to get it to begin to take that curve but without making any huge change to any one cell. and then log data, update table, look at it in 2d or 3d and smooth it and log more data. IT does take time and patience. First try to get fuel trims to within -5% to 0 but never +1%. Later on once you have a good all around tune and you have some time and experience under your belt you can try to get it down to the -2%. But honestly within 5% of target is damn close and better than most on this forum will achieve. So you shouldn't go beating yourself up trying to chase such an accuracy at this point.
And of course after you are done with the maf table calibration to complete the tuning process you will need to set the high rpm disable back to 4,000 or wherever you would rather the ecu start to prefer the maf sensor over the map sensor and then you will want to turn back on the COT, DFCO, and PE. And you should have a good running tune
so i when i have been doing the ve logs i was using stft not ltft. one thing i read says to disable the long term fuel trims. guess that was no correct? that maf table was done by a pro shop i used. glad i wasted that money... i am having a hard time getting many cells to log in the upper rpms. i get a good count in the lower then 4000 but can only get a few cells in the upper end. how do you get all the cells logged? i found how to set up the maf calibration tables and am setting up my table now. seems like i will have to do a lot more work on my ve table first. thank you for the info.
I would be careful about using the word 'pro' when discussing that maf calibration. I like LTFT data. I know it takes longer to populate but I find it is more accurate for me. I configure my histo / charts to require 5 cell hits to make changes also so that I am only logging true and correct data. And you know in between uploading changes to ecm and logging more data, make sure you are resetting fuel trim data so you aren't populating charts with data from before you uploaded your latest changes. Also I make sure the car stays in closed loop so it keeps fetching good data. As stated I disable the PE. and then tune as much of the map as accurately and carefully as I can. And without ever going to full throttle or getting the motor to 6500rpm I can still get a good idea of what kind of shape the ve table or maf calibration is going to take.
i say pro cause that is what they do for a living. build and tune ls motors. I sure hope they spend more time on the really high dollar motors they tune like the new zo6 and such. I think cause its a truck they just blew threw it and did take much time or pride in there work. any ways i went and logged some ltft and adjusted my ve again. most of the time it was around -2 to -3 just at idle one of the trims went to 12 or higher. not sure what that is all about. i will post the tune and log. i like the ltft better so far. thanks for all your help so far.last ve drive.hplFLACCO FRIST SMOOTH VE TABLE v3 sd mode for ve tune.hpt
Looks better and don't forget to set the MAF dtc's to fail on first error for speed density tuning. As well as removing the MAF channels from your logs to prevent data skewing.
Stick a stock MAF curve back in that thing once you start tuning the MAF again, I wouldn't even attempt to try and save that crap looking curve. Start from square one again.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
i have an 06 with a 5.3 i could barrow the maf curve from. how do you know when the ve table is done? guess when fuel trims are around 0-3 all the time?
just make sure it is always 0, -1, -2, or -3 and never positive numbers.
How do you make it just follow the maf and not ve table
Lower the dynamic airflow settings from stock 4,000ish down to like 200 and 100.
If will use the MAF sensor for mostly everything but will always reference the VE for transient fueling, though that won't be something you notice when you are slowly building your new MAF curve.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
By driving it like it's stolen..Originally Posted by 85LSburb
and for longer periods..
and driving it differently than you normally would.. like different loads/gears/speeds...
One unpleasant and nasty thing you can do is drive with your foot on the brake. Its not nice... nor is it safe, but it lets you see some higher load cells. Don't use the handbrake, it will fry it...
99 TA, Texas Speed LS376, PRC heads, 233/239 cam, Fast 92mm, 95mm TB, card style MAF, Tick TR6060, Strange 4.11 12 bolt axle & clutchpack diff, Strano springs/dampers, Vette 18" wheels, Vette disks, CTS-V calipers, 16lb flywheel, long tube headers, no cats.
Pay for some time on a load bearing dyno.
knock it out in a couple hours.
So when I start maf tuning do you flash the ecm back to normal operation as in setting everything to factory specs you turned off or adjusted to tune ve?
The tuning the right way course comes with an entire book dedicated to gm maf and ve tuning. If you follow the order in the book, you are to disable PE by setting all power enrich enable tps cells to 100% for both hot and cold. Then disable COT lean cruise by setting it to disabled and disabling DFCO by setting the enable temp to 250. Now that the variables that can provide false data to our ltft or afr correction are disabled we can tune the ve table by disabling the maf by setting the maf fail high hz to 0. Now we can log and tune the ve table. Which we should do first. Just part throttle and idle and cruising. No need for wide open throttle just yet.
Once we have a good idea of the shape our ve table is going to take, still without going to full throttle we can logically determine about where the dropoff on the ve table should be on each of its axes simply by understanding where the motor makes its peak power. And it's peak efficiency or the high spot on the ve table should be just before peak output. Once we have a shape that matches what we know a good ve table should look like and it jives all over the place with our ltft at part throttle and cruising and idle, then we can start to go further into the higher loads and make sure that our trims don't start adding fuel or taking away a whole bunch.
Once we are satisfied with how the ve table is and we are ready for maf tuning, we turn the maf back on by resetting the maf fail high hz to 13,500 or whatever it was and then we disable the dynamic airflow by changing the high rpm disable from 4,000 to 200. Even though the maf table is 2d and has less axes tuning strategies are principals are exactly the same. When you have a good ve map and a good maf calibration and both are smooth and jive all over the place set the high rpm disable back to 4,000. Then you will want to re-enable the COT lean cruise if you have cats. You will also need to change DFCO enable temp back to a low number so as to enable it. And you will maybe want to load up another instance of hptuners with an old copy of your tune so you can just goto your pe enable tps hot and cold tables and just copy and paste them back to their original states.
And you should have one mean if not professional tune, bud.
Last edited by AutoWiz; 05-29-2017 at 02:12 PM.
Sorry. Forgot you already went over maf tuning. I may look into the tuning book. What one do you recommend? I will have to put the tune on hold until next weekend. Truck is out of gas and my account is out of money. Thanks for all the help!!!
you can get that course here: https://www.hptuners.com/order.php
Tuning the right way GM level 1.
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