TUNING MAFLESS ?

[Last Call]

Hi guys

i am new here and new with using EFIv7 live tuning tool.The quetion i have is how do you turn the maf of to do a mafless tune ?any help will be appreciated

regards sonny

[Dirk Diggler]

At the moment you have to unplug it in later releases we will be able to force it off

[johnsZ06]

At the moment you have to unplug it in later releases we will be able to force it off

If you unplug it can you suppress the SES lamp?

[Dirk Diggler]

Yes but if you supress the ses lamp it wont really go into SD so I have read. I have tuned my car mafless and use the light as a reminder that a mafless tune can be done :lol: But i have read on ls1tech if you supress the code it never defaults to sd mode

[Steve Bryant]

Here is a way to go MAFless without unplugging anything.

1. Go to the Engine Diagnostics portion of the tuner software and look at MAF Parameter {C2901} MAF High Frequency Fail 1. This is the upper limit trip point that the PCM uses to monitor normal operation of the MAF sensor. Set this value to 0.

2. Go to {C6002} Engine DTC Enablers and set P0103 to No MIL

3. Make a note of the what you have done in the Comments Section so you can undo this change later like:
Set MAF Hi Freq Fail 1 to 0 to disable MAF, normal value is 14,000
Set {P0103} to No MIL

4. Save the file with a descriptive file name of your choice. I like to use names like MAF Disabled Tune 1.tun for the first iteration and MAF Disabled Tune 2.tun for the second iteration and so on.

5. Hook up your laptop and FlashScan interface to the PCM via the OBD2 port and flash the tune.

Here's what will happen. As soon as you start your vehicle the PCM will decide that the MAF has failed because it is exceeding the prescribed limit for normal operation (which you just intentionally set to the bogus value of zero). This would normally trip the Malfunction Indicator Lamp (aka MIL, aka Service Engine Soon/SES). However, when you set diagnostic trouble code (DTC) {P0103} to No MIL you told the watchdog monitor of the PCM to disregard the {P0103} code and you will not get a light. Now you can work with the speed density portion of Open Loop operation.

Also, as a prerequisite, you should disable Closed Loop Operation by setting the Closed Loop Temp Enable values to the maximum value in degrees C or F (whichever you are using) which is parameter {B4205} located at Engine Calibration\Fuel\Trim\Closed Loop Temp Enable. Then you can use a WBO2 as your AFR guide for getting the values correct in the Back Up VE table if you have a pre 2001 operating system or the Main VE table if you have an Operating System in the PCM that is 2001 or later.

You could also leave the closed loop enabled and use Short Term Fuel Trim for cylinder banks 1 and 2 (SHRTFT1/SHRTFT2) to determine what it takes to get slightly negative values like -1 for each cell of the VE table. You will need to make your own map/pivot table/histogram to do this. This is what you would do if you didn't have a WBO2. However, I would strongly encourage you to spend the money to get a WBO2 as soon as possible because tuning without a WBO2 is like flying trapeeze without a net. Plus you cannot accurately adjust anything related to mixture very well. You can't accurately adjust anything related to power enrichment at all.

This post is getting a little longer than I want for a post, but I want to give you the main concepts.

All my best,

Steve

[curtbriggs]

Steve, Thank you for the detail in your post. For those of us that are learning, I for one really appreciate a post that I can understand.

Thanks, Curt

[Last Call]

Steve

thank you for a very informative post,by now i had worked out that no mil was the go,now i have to work out the rest of it as this is all new to me,thanks

regards sonny

[hpcubed]

I set my maf fail frequency to 0 and uploaded the program. I do not get a MIL light. How do I truly know that I am in speed density mode?

[Steve Bryant]

First, just remember, I'm not a professional tuner but someone who is learning himself and has been a student of tuning for about a year.

Now, I have three ideas to validate SD operation:

1. you should be able to see a P0103 Diagnostic Trouble Code on the OBD II (F7) DTC page when scanning the vehicle. Although I would have thought the SES light would have been illuminated.

2. Save your current tune file as another file name and set all of the MAF flow values for all frequencies to zero. In other words you're telling the MAF that no air is flowing no matter what the frequency being output from the MAF Sensor. Be sure and save your old file in a safe place so you can reinsert the correct values later. If you are in Speed Density and the MAF has been totally set to Zero, all the PCM has left is the volumetric efficiency table, IAT, ECT, cylinder displacement, etc to tell it some mathematically calculated flow data since the MAF isn't supplying any measured flow information. If the vehicle will run under these circumstances you must be in speed density for the foundation air mass flow data. You might still have closed loop enabled, but the engine won't run on NBO2 data alone.

3. If your vehicle is an automatic, I find that the shifts are much firmer and have less finesse. This for me is evidence that it is in speed density.

Others chime in if you have more ideas.

All my best,

Steve

[dbaxter_ss]

Hope this helps, it was given to me for adjusting the MAF freq. Works Great!!!

Log with the MAF either to fail immediately or unplug it, get at minimum gm.dynair, gm.maffreq and rpms. Go for a nice long drive so you can try to get as many fq's as possible.

load up you log and tune. use this MAP, make sure you're using the averages. Select the whole column, copy special. Goto TUNE and drill down to MAF sensor Calibration, select the column and paste special.

I was told to leave the little peak and valleys, but just did not look right to me so I smoothed out the way out stuff to make a cleaner curve, then did a quick smoothing.

Mine MAF is set to fail at like 10.

before
http://www.purplegto.com/files/maf1.png
after smoothing
http://www.purplegto.com/files/maf2.png


MAF MAP \/ CLICK ON THIS LINK TO DOWNLOAD THE MAP FILE
http://www.purplegto.com/files/EFI-MAF.zip

[Steve Bryant]

dbaxter_SS

I want to study this closely because I think that it may be better for tailoring the MAF than a method that I've developed but haven't talked about yet because I've not spent enough time with it yet to be telling others.

My question is this, how did you post the two graphs? That function is broken on the bulletin board software for most of us and yet you've been able to post the graphs.

All my best,

Steve

You were right by the way to take out the zig-zag stuff out of your value table and smooth out the curve in my opinion.

[Dirk Diggler]

On tech if you look under my user name HumpinSS I speak of using Efilive to recalculate the MAF sensor. Pretty much all you do is set the fail freq to 0 dial in your ve table, after this is done make a map that logs freqency and rpm=8000 and the data is Dynair in g/sec IIRC. After the scanner plots the averages for the cell you hit you can copy this table back to you maf table set the fail freq back to stock and go aobut you merry way.

I also have another idea but havent gotten around to trying it.

Log frequency against actual AFR. then divide actual by commanded and you should be able to see how far off your maf table is. Since this tale is a 1:1 type of deal you should be able to get it right on the first iteration of logs. After this is done you can then get accurate calc ve values from the calc pids provided by efilive

[Steve Bryant]

Thanks Dirk, I have made some maps like this in the past correlating a variety of PID's like MAF Frequency and MAF at various RPM and MAP Cells to correlate the MAF to the VE. I have an excel spread sheet set up to choose one of six curve acceleration rates that one can use to match things up.

Thanks again for your input. We're all learning together. However, right now is a wonderful time to be learning this stuff because there's already a lot of trial and error stuff available for us to look at on LS1 bulletin boards and good people like you and dbaxter_SS who are willing to talk and share.

Now with EFILive V7 and FlashScan we have wonderful tools to work with and wonderful people at EFILive who are really responsive to the needs and desires of their customers.

All my best,

Steve

[dbaxter_ss]

dbaxter_SS
My question is this, how did you post the two graphs? That function is broken on the bulletin board software for most of us and yet you've been able to post the graphs.

using the IMG buttons. I host on the pics my own server, if you right click on the pics and goto properties you will see they are on my site purplegto.com
ex
http://www.purplegto.com/files/maf2.png



You were right by the way to take out the zig-zag stuff out of your value table and smooth out the curve in my opinion.

I kind of figured, as you could see they were WAY all over and I didn't think it should stay that way.

Dirk - The MAP I linked at the bottom of my post is the MAP I talked about. Just click and save the ZIP file and put the map inside into your maps. Does just what you say to do: If you guys can't save it just pm me your email and I will gladly email it to you.

http://www.purplegto.com/files/EFImafMAP.PNG

[jfpilla]

I set my maf fail frequency to 0 and uploaded the program. I do not get a MIL light. How do I truly know that I am in speed density mode?

The GM.MAF Pid will not log any values. The SAE.MAF will.
After 1998 you will not notice any impact on the A4.

[dbaxter_ss]

Not GM.MAF

GM.MAFFREQ HZ and GM.DYNCYLAIR

These both log on my 2001 SS and 2004 GTO.

Btw: using EFI Tune and on the maf freq I noticed something so cool. Just clicking and holding the mouse and following up the graph not clicking on each little dot, it would put that cell right were the mouse was.

[hpcubed]

I set my maf fail frequency to 0 and uploaded the program. I do not get a MIL light. How do I truly know that I am in speed density mode?

The GM.MAF Pid will not log any values. The SAE.MAF will.
After 1998 you will not notice any impact on the A4.

Ok thanks. It seems that mine is logging data in both pids so maf freq. fail must not be working. I will download the program to see if it was uploaded

[hpcubed]

Well I found out why I was not getting the mil lamp. The guy who originally tuned my car had the Engine DTC Process Enablers for the high frequency fail disabled. That is why my car would not run when I unplugged the maf. So essentially since he did not touch the VE table, he set the computer to not be able to do any transient corrections from the VE. Essentially he set it to only go by the maf - correct? It ran pretty good that way though.

Edit: Statement is incorrect. By doing the above, the car should still use the VE table. But there probably is a good reason (as far as money is concerned to disable this function.

Now when I set maf fail to 0 my car idles like s***. I can smell it is running rich and it is kinda popping a little out the exhaust. Their is no maf data on the "dashboard" when monitoring but there is data being recorded for both maf freq. and air mass in the "Data" tab. I guess I have to adjust the VE table for idle now.

[jfpilla]

Well I found out why I was not getting the mil lamp. The guy who originally tuned my car had the Engine DTC Process Enablers for the high frequency fail disabled. That is why my car would not run when I unplugged the maf. So essentially since he did not touch the VE table, he set the computer to not be able to do any transient corrections from the VE. Essentially he set it to only go by the maf - correct? It ran pretty good that way though.

Now when I set maf fail to 0 my car idles like s***. I can smell it is running rich and it is kinda popping a little out the exhaust. Their is no maf data on the "dashboard" when monitoring but there is data being recorded for both maf freq. and air mass in the "Data" tab. I guess I have to adjust the VE table for idle now.

MAF freq and SAE maf will log. GM maf should not.

[hpcubed]

Well I found out why I was not getting the mil lamp. The guy who originally tuned my car had the Engine DTC Process Enablers for the high frequency fail disabled. That is why my car would not run when I unplugged the maf. So essentially since he did not touch the VE table, he set the computer to not be able to do any transient corrections from the VE. Essentially he set it to only go by the maf - correct? It ran pretty good that way though.

Now when I set maf fail to 0 my car idles like s***. I can smell it is running rich and it is kinda popping a little out the exhaust. Their is no maf data on the "dashboard" when monitoring but there is data being recorded for both maf freq. and air mass in the "Data" tab. I guess I have to adjust the VE table for idle now.

MAF freq and SAE maf will log. GM maf should not.

I assume GM maf is what controls the maf on the dashboard?

[hpcubed]

Another question: With the maf disabled, the "idle airflow" parameters will be ignored? The computer is only using the VE table for air mass?

[jfpilla]

Another question: With the maf disabled, the "idle airflow" parameters will be ignored? The computer is only using the VE table for air mass?
No, they continue to function.

[hpcubed]

Another question: With the maf disabled, the "idle airflow" parameters will be ignored? The computer is only using the VE table for air mass?
No, they continue to function.

Ok, I understand the "effective area" is used and not maf.

So why do you think my car is idleing so rich when I unplug the maf? Is the VE table off or should I look elsewhere?

[jfpilla]

Another question: With the maf disabled, the "idle airflow" parameters will be ignored? The computer is only using the VE table for air mass?
No, they continue to function.

Ok, I understand the "effective area" is used and not maf.

So why do you think my car is idleing so rich when I unplug the maf? Is the VE table off or should I look elsewhere?

It's very likely the VE's. I'm assuming you are cammed. Start by lowering the VE's at 1200 by 15% 800 by 10% 400by 5%. That's to get you running well enough to log. Set your trims negative, using the VE table, then hook up the MAF. Reset the trims through the MAF table.
If you have stock injectors leave the IFRs stock. That will allow you to calculate your PE values.

Suggest you list your mods when asking for help.

[hpcubed]

Another question: With the maf disabled, the "idle airflow" parameters will be ignored? The computer is only using the VE table for air mass?
No, they continue to function.

Ok, I understand the "effective area" is used and not maf.

So why do you think my car is idleing so rich when I unplug the maf? Is the VE table off or should I look elsewhere?

It's very likely the VE's. I'm assuming you are cammed. Start by lowering the VE's at 1200 by 15% 800 by 10% 400by 5%. That's to get you running well enough to log. Set your trims negative, using the VE table, then hook up the MAF. Reset the trims through the MAF table.
If you have stock injectors leave the IFRs stock. That will allow you to calculate your PE values.

Suggest you list your mods when asking for help.

Thanks for the info jfpilla I will try what you suggest. Mods are now listed. I have been studying for about a month now and I think I got a pretty good handle on a lot of this stuff. But I don't quite understand what you meant by calculating the PE values if the IFR's are stock. How do you calculate the PE values? I thought that was determined by wideband or stock O2's?

[jfpilla]

Another question: With the maf disabled, the "idle airflow" parameters will be ignored? The computer is only using the VE table for air mass?
No, they continue to function.

Ok, I understand the "effective area" is used and not maf.

So why do you think my car is idleing so rich when I unplug the maf? Is the VE table off or should I look elsewhere?

It's very likely the VE's. I'm assuming you are cammed. Start by lowering the VE's at 1200 by 15% 800 by 10% 400by 5%. That's to get you running well enough to log. Set your trims negative, using the VE table, then hook up the MAF. Reset the trims through the MAF table.
If you have stock injectors leave the IFRs stock. That will allow you to calculate your PE values.

Suggest you list your mods when asking for help.

Thanks for the info jfpilla I will try what you suggest. Mods are now listed. I have been studying for about a month now and I think I got a pretty good handle on a lot of this stuff. But I don't quite understand what you meant by calculating the PE values if the IFR's are stock. How do you calculate the PE values? I thought that was determined by wideband or stock O2's?

If your injector flow rate table has stock values and you have stock injectors, you can calculate your desired PE rpm. If you divide 14.7 by the desired AFR you get the value for PE modifier rmp in mixture tab.
EX:14.7/13.0=1.13(modifier) 14.7/12.6=1.167

[GMPX]

If your injector flow rate table has stock values and you have stock injectors, you can calculate your desired PE rpm. If you divide 14.7 by the desired AFR you get the value for PE modifier rmp in mixture tab.
EX:14.7/13.0=1.13(modifier) 14.7/12.6=1.167

Or in the properties list in the Tuner select to view these values as AFR, not EQ.

Cheers,
Ross

[hpcubed]

Leaned out the mixture as jfpilla suggested and now the car idles fine. So now I am off and tuning.

Thanks.

[jfpilla]

If your injector flow rate table has stock values and you have stock injectors, you can calculate your desired PE rpm. If you divide 14.7 by the desired AFR you get the value for PE modifier rmp in mixture tab.
EX:14.7/13.0=1.13(modifier) 14.7/12.6=1.167

Or in the properties list in the Tuner select to view these values as AFR, not EQ.

Cheers,
Ross

Ross,
Nice feature. I can put the calculator away.
thanks
Joe

[hpcubed]

Did some logging. My trims are all in the -9 to -15's in the lower half of the map values. I can understand my volumetric efficiency being lower than a stock cam at low rpms but it seems that by 4000 rpm, the engines VE should be better than stock? Is this typical for a heads/cam engine?