LNF Maf Calibrating w/ PICS.

[powermizer]

So does this mean each time I drive to get the maf calibration dialed in I need to go into the tune and keep changing the maf correction table to 1s ? Just seems like it shouldn't change.

[T-Man]

So does this mean each time I drive to get the maf calibration dialed in I need to go into the tune and keep changing the maf correction table to 1s ? Just seems like it shouldn't change.

Your MAF correction table, if changed to all 1s and saved/write-cal only to the ECU, shouldn't change?

[powermizer]

Thanks for your reply T-Man. I did save it and write cal only. I had no reason to look at the correction table on the tune, So when I did a week later I noticed most of the cells were still 1s, but I had some that were starting to show other numbers. I will put them back and see what happens. This really threw me off.

[Grant LS1]

Hi There all but especially cobaltssoverbooster,

I have just been told by HPT direct that if you adjusting the MAF frequency you HAVE to adjust the desired airload.

The car I'm tuning isn't seen in the U.S. but runs the same PCM therefore similar parametre setup, I've just changed the MAF location from near the airbox to literally a couple of inches from the throttle body with O.T.R. air cleaner.

Now I have a base setup from another tune & even to get it to idle after crank start it needs 40% extra fuel but if I go over 20% over the stock MAF the car won't run it fires up & goes to 2,000 rpm & then stalls! If I give it a little bit of accelerator it pop's & bucks all over the place just to run around 1,500 rpm now I wouldn't have thought the desired airload table would have much if any affect down that low.

I have been able to get fuel trims to +/- 1 with giving the MAF extra 20% on stock table & having to adjust injector rate to an extra 30% (even though there stock injectors) & adjusting off the fuel trims with base table!

I don't really want to have it leave the shop like that but only real work around seeing MAF table didn't like too much adjustment?

Good to know about the evap plug disabling the ltft I hope we have that on our cars over here, I don't know why they dont just enable the ltft temp scalar parameter to disable it?

Cheers Grant

[mkriebs]

Grant, what size of tube do you have the MAF in? We generally use 3" since that is as close to the factory as we can get it. I am also having an issue with my relocated MAF sensor, where I think I have it in an area of dead airflow through the tube because of the aerodynamics of the throttle blade when it is closed or partially closed. This would result in a skewed MAF and the inability to dial in the tune. The solution to this that I am going to try is to build a new boost tube and move the MAF further from the TB.

Does the car run better with the MAF unplugged?

Furthermore, I would change the injector constant back to the stock values. I would also start fresh with new MAF tables (all 1 in the correction table, and stock values in the frequency table). I don't see any reason it would not start as long as you used a 3" tube.

[cobaltssoverbooster]

The DAL is an air load request table. You don't always have to adjust it when maf tuning but it is.a good idea to adjust while maf tuning to lock down the airflow requirement. If your idle has the throttle blade open more than 4 % at idle try adjusting the dals to lower the airflow requirement. It doesn't take a lot of air to idle and gm runs them high so chances are lowering the requirement some may help smooth you out as well.

You can leave the dals alone and calibrate the maf to account for the air the dals command but if you change the dals then you will have to go back and make a. A correction because you changed the air requirement.

And where is your maf? It does sound relocated due to the offset.
What type of fuel are you running? Some countries run ethanol everywhere so that's important to knowas well.

[Jmmahon]

Hey guys, I couldn't find another thread to post to so I'll use this one.
While reviewing my MAF Airflow vs. output freq table during MAF tuning I noticed at 1,260 HZ there was a spike in that cell. Could anyone give me an answer why?

[MikeOD]

Hi guys. I'm working on an LNF, and I've got the MAF frequency table pretty close with the correction table set to 1.0 everywhere.

I want to fix that, but there are a few engine LOAD settings I can log for the top axis of that table...calculated load, air load... I haven't really watched if they differ much from each other yet, but I wanted to make sure I reference the right one for that axis. As I'm using 3.0, the older config files on this thread won't open at all. If anyone can let me know which load parameter they log as the top axis, that'd be great. If not I'll figure it out in a day or 2.

[metroplex]

I used Absolute Load (SAE), if this is for the VCM Scanner table for MAF Correction. It goes to 190.

If this is for the MAF Frequency, the column axis should just be Mass Air Flow Frequency (Sensor) with no row axis. The instructions for setting up the VCM Scanner layout in VCM 2.0 is the same as 3.0

[MikeOD]

I used Absolute Load (SAE), if this is for the VCM Scanner table for MAF Correction. It goes to 190.

If this is for the MAF Frequency, the column axis should just be Mass Air Flow Frequency (Sensor) with no row axis. The instructions for setting up the VCM Scanner layout in VCM 2.0 is the same as 3.0

Yeah, I setup the 2 tables no sweat...I logged and fixed the frequency table pretty easily...but I see the value of the load/correction table on this car/setup, just want to make sure I log against it correctly. I'll use absolute load and see how it works. Thank you for the help.

[street253]

I'm having real high LTF1 and i'm trying to see the data in the other columns, but only column 500,000 is showing any data. I know in the old vcm scanner it couldn't fit all the values, but in 3.0 all the values fit on one line. Is their something i have to change?

Thanks in advance

[HackAbuse]

I'm having real high LTF1 and i'm trying to see the data in the other columns, but only column 500,000 is showing any data. I know in the old vcm scanner it couldn't fit all the values, but in 3.0 all the values fit on one line. Is their something i have to change?

Thanks in advance

Try inverting your axis, so smaller values first, then ascend, ending with 500,000 instead of starting.

[HackAbuse]

Just a theory, but I'm pretty sure VCM Scanner is only setup to be able to deal with ascending data sets

[ECaulk]

What's your user math you're using?

Also do you see a maf freq in the scanner while driving?

[ECaulk]

Just a theory, but I'm pretty sure VCM Scanner is only setup to be able to deal with ascending data sets

It can handle descending data sets, it really doesn't care as long as the correct info is logged. The issue is most likely not correctly calculating the math or the maf freq isn't logging correctly therefore populating the first cell (could be wrong parameter selected or an error with the maf).

[HackAbuse]

It can handle descending data sets, it really doesn't care as long as the correct info is logged. The issue is most likely not correctly calculating the math or the maf freq isn't logging correctly therefore populating the first cell (could be wrong parameter selected or an error with the maf).

Usually when I experience the issue he's seeing, it's because i fat-fingered in a decimal or a zero on the next data set

[street253]

What's your user math you're using?

Also do you see a maf freq in the scanner while driving?

i dont see maf freq while driving. i took the pid straight from the list.

Usually when I experience the issue he's seeing, it's because i fat-fingered in a decimal or a zero on the next data set

i tried your method still no luck. i appreciate the help though.

[MarkTucker]

You need to add MAF Frequency to be logged in the channel list. For any parameter that you are trying to log in the graph, chart, or gauges, it needs to be added to the channel list(in less it is a Math Function. Then the parameters needed for that Math Function, for the Math Function to work).

[cobaltssoverbooster]

^x2 hpt can read an inverted axis...at least i have had it do that for me. most people only log one cell because the axis header sensor selection does not match the sensor that is on the channel list selection.

[street253]

You need to add MAF Frequency to be logged in the channel list. For any parameter that you are trying to log in the graph, chart, or gauges, it needs to be added to the channel list(in less it is a Math Function. Then the parameters needed for that Math Function, for the Math Function to work).

This was the issue! Thank You

^x2 hpt can read an inverted axis...at least i have had it do that for me. most people only log one cell because the axis header sensor selection does not match the sensor that is on the channel list selection.

I have been reading/watching all your guides. Good info man really appreciate the effort put in.