Tuning w/o AutoVE

[VetPet]

I'm interested in knowing how you would tune your car if you're only using a WB02 for WOT tuning on a dyno. I've logged my data and created several different MAPs in scan tool (LTFT's, KR). Would you still use your average LTFT's to adjust the VE table or would you tune using the MAF table instead? I've got a C.A.I. system I recently installed and my new LTFT's are much higher (positive) than they were before. I know AutoVE tuning is the way to go (eventually I'll get there) but for now, I need some help doing it the 'old way'. Would someone be willing to help step me through the process? I know I need to get the LTFT's down to zero or negative but am not sure how to go about it. I would really appreciate some help.

:)

[Blacky]

Step 1. Do the AutoVE tuning thing with the MAF (temporarily) removed (or disabled) to get your VE table correct. Once the VE table is accurate...
Step 2. Replace the MAF and recalibrate the MAF based on the (now accurate) VE table.

(this is all off the top of my head, it may contain a few "stupid moments", and I may go back and correct it later, but you should get the idea of what to do).

To do step 2...
You need to create a MAF map similar to the VE BEN factor map. It will log a calculated PID (based on the error between measured airflow and predicted airflow) against MAF Hz (rows) and RPM (one column only with label "Value")

Hint, when creating a scan tool map, "copy with labels" the entire MAF calibration from the tuning tool. Then use the scan tool MAP property editor to [Paste labels] for the rows. That will automatically paste in the MAF row labels. Saves typing them all in.

The calculated airflow error PID is similar to the BEN PIDs, except where the BEN PIDs use AFR, this one will use airflow.

i.e. airflow error = (measured air)/(predicted air)
which is really {GM.CYLAIR_DMA}/{GM.DYNCYLAIR_DMA}

Then once you have the error map logged in the scan tool, "copy with labels" the entire table and then select the first row of the MAF calibration and "past and multiply with labels".

Regards
Paul

[jfpilla]

I'm interested in knowing how you would tune your car if you're only using a WB02 for WOT tuning on a dyno. I've logged my data and created several different MAPs in scan tool (LTFT's, KR). Would you still use your average LTFT's to adjust the VE table or would you tune using the MAF table instead? I've got a C.A.I. system I recently installed and my new LTFT's are much higher (positive) than they were before. I know AutoVE tuning is the way to go (eventually I'll get there) but for now, I need some help doing it the 'old way'. Would someone be willing to help step me through the process? I know I need to get the LTFT's down to zero or negative but am not sure how to go about it. I would really appreciate some help.

:)

If I understand, the only mod you have is a CAI? Just multiply the MAF table by the % that the trims are positive. Guess at an average that the trims are positive. Repeat the process till you have the trims from 0 to -7 or so.

[VetPet]

These are the mods that I have.

1. Hurricane C.A.I. system
2. LT headers, random tech cats, X-pipe, Z06 cat back.
3. LS6 Ported heads
4. Comp Cams 212/218

The C.A.I. has really made a change to my LTFT#'s when I compare them to my pre C.A.I. install. Is there anything I should change in my tuning method?

Thanks Guys :)

[jfpilla]

These are the mods that I have.

1. Hurricane C.A.I. system
2. LT headers, random tech cats, X-pipe, Z06 cat back.
3. LS6 Ported heads
4. Comp Cams 212/218

The C.A.I. has really made a change to my LTFT#'s when I compare them to my pre C.A.I. install. Is there anything I should change in my tuning method?

Thanks Guys :)

If your not tuning VE's and the car starts and runs well, just do the MAF as above, and get the ltrims close.
It's the way it was done for years. If you run the MAF it will run like it's supposed to.

[VetPet]

Thanks for the help guys. If I use the MAF table to tune, would I just take an average of the LTFT's by adding them all up and dividing by the number of cells or should you weigh each of the cell values by multiplying the cell value by the number of counts first, adding up the total cell values and then divide by the total number of cell counts for the entire table? Will this get you a more accurate average to multiple the MAF table by? If the average LTFT turns out to be 10% you would then multiply the grams/sec column values by 110%, am I correct? Also, would your average LTFT value be a blend of both banks 1 & 2 for this exercise? So many questions.

:)

[jfpilla]

Thanks for the help guys. If I use the MAF table to tune, would I just take an average of the LTFT's by adding them all up and dividing by the number of cells or should you weigh each of the cell values by multiplying the cell value by the number of counts first, adding up the total cell values and then divide by the total number of cell counts for the entire table? Will this get you a more accurate average to multiple the MAF table by? If the average LTFT turns out to be 10% you would then multiply the grams/sec column values by 110%, am I correct? Also, would your average LTFT value be a blend of both banks 1 & 2 for this exercise? So many questions.

:)

My preference is to wing it. Your trims will change based on weather driving up hill and down, etc. You will probably find certain cells are more/less neg. or pos. than the rest. Get them in range and don't worry. It will not make a difference.

[VetPet]

O.K. then. So in order to properly tune the VE table, you have to use SD mode to collect data, otherwise use the LTFT's to make adjustments to the MAF table. You shouldn't use any LTFT data to adjust the VE table, especially if not logged in SD mode. Why is there such a concern about touching the MAF table, or even the IFR table for tuning? VE tuning seems to be where it's at right now but I've seem a lot of comments against tuning that way. Enquiring minds would like to know.

8)

[jfpilla]

O.K. then. So in order to properly tune the VE table, you have to use SD mode to collect data, otherwise use the LTFT's to make adjustments to the MAF table. You shouldn't use any LTFT data to adjust the VE table, especially if not logged in SD mode. Why is there such a concern about touching the MAF table, or even the IFR table for tuning? VE tuning seems to be where it's at right now but I've seem a lot of comments against tuning that way. Enquiring minds would like to know.

8)
http://www.ls1tech.com/forums/forumdisplay.php?f=7

Suggest you go here. There is a lot of info and answers.

[ToplessTexan]

My preference is to wing it.

:lol:

[caver]

When running with the maf connected the pcm uses that for all its input while keeping an eye on the VE table to make sure the maf is signals are legit.
If the maf table is to far out it will bring up a maf/map comparison dtc.

This works for me. I have a maf map like blacky described so I log using a WB02 on the dyno full throttle and part throttle to cover all the cells.
LTFT must be disabled when you do this.

I then paste and multiply that data into the maf fequency table.

If its far out like a ben factor of 1.06 then I will move the whole maf table up by about 3%, be gentle a little goes a long way.

Using this I can normally get my ben factor between .99 and 1.01 in 2 or 3 attempts.
Max about 45 minutes dyno time including doing the timing table.

[VetPet]

Step 1. Do the AutoVE tuning thing with the MAF (temporarily) removed (or disabled) to get your VE table correct. Once the VE table is accurate...
Step 2. Replace the MAF and recalibrate the MAF based on the (now accurate) VE table.

(this is all off the top of my head, it may contain a few "stupid moments", and I may go back and correct it later, but you should get the idea of what to do).

To do step 2...
You need to create a MAF map similar to the VE BEN factor map. It will log a calculated PID (based on the error between measured airflow and predicted airflow) against MAF Hz (rows) and RPM (one column only with label "Value")

Hint, when creating a scan tool map, "copy with labels" the entire MAF calibration from the tuning tool. Then use the scan tool MAP property editor to [Paste labels] for the rows. That will automatically paste in the MAF row labels. Saves typing them all in.

The calculated airflow error PID is similar to the BEN PIDs, except where the BEN PIDs use AFR, this one will use airflow.

i.e. airflow error = (measured air)/(predicted air)
which is really {GM.CYLAIR_DMA}/{GM.DYNCYLAIR_DMA}

Then once you have the error map logged in the scan tool, "copy with labels" the entire table and then select the first row of the MAF calibration and "past and multiply with labels".

Regards
Paul

Hi Paul, I've got the basic idea of what we're trying to achieve but am having a problem with some of the "how to" stuff. I'm referring to the AutoVE tuning tutorial and your comments below to try and explain myself.

1. Select PIDs for AutoVE

Since I'm not using a WB02 sensor I can delete the PIDs for Calc.AFR and Calc.Ben. I will however, need to add two other PIDs, {GM.CYLAIR_DMA} & {GMDYNCYLAIR_DMA}. These are needed in order to calculate an airflow error PID.

2. Create an AutoVE MAP

Here's where I'm getting stuck. How do I create a MAF map that's similar to the VE BEN factor MAP? I don't understand how you are going to create a similar MAP that will log a calculated PID based on the error between measured airflow and predicted airflow even though I know we are logging the individual parameters.

The MAF table in tune shows frequency vs grams/sec. This is the table we want to adjust based on the error airflow calculations. If you "copy with labels" the MAF table and then "paste labels" for the rows using the MAP property editor you'll copy the frequencies into the scan tool MAP. So now you have a table with frequencies for the rows and only one column for values (error airflow factor). How do you come up with the error factor correction that goes in this column? I know we've got the two PIDs needed to calculate it but how does it get calculated? What have I missed?

Thanks for your help.
:?

[Blacky]

Add the three entries to \My Documents\EFILive\V7\User configuration\calc_pids.txt


# ================================================== ============================
# Units
# -------------------
# See sae_generic.txt for more information on the *UNITS section

*UNITS

#Code System Abbr Description
#-------- ---------- -------- -------------------------------------------------------------

BAFN None "%" "Base Airflow Numerator"


# ================================================== ============================
# Add slot definitions here
# --------------------------------
# See sae_generic.txt for more information on "SLOT" formats
#
#Units Low High Fmt Expression
#------------ ------------- ------------- ---- --------------------------------------------------------------
*CLC-00-100
BAFN 0.0 2.0 .2 "{GM.CYLAIR_DMA}/{GM.DYNCYLAIR_DMA}"


# ================================================== ============================
*PRN - Parameter Reference Numbers
# --------------------------------
# See sae_generic.txt for more information on the *PRN section
#
#Code PRN SLOT Units System Description
#------------------------- ---- ------------ ---------------- ---------------- ------------------------------------------
CALC.BAFN F100 CLC-00-100 BAFN Air "Base Airflow Numerator"


Then create a map with the following PIDs:
Data = {CALC.BAFN}
Rows = {SAE.RPM} (Set Col labels to: ",Value")
Cols = {SAE.MAF} (Set Col labels: "Copy with labels" from MAF cal in tuning tool - then use the [Paste labels] buttons).
Cells tab page: Check, constrain cell size. Use values: Min: 32, 18 and Max: 64 and 18

Regards
Paul

[VetPet]

Hi Paul, Thank You for the info. You'll have to excuse my ignorance of this subject matter....this is all brand new to me. You've asked me to enter the three lines into my calc_pids.txt. Is this file the same as what you've displayed except for the three lines of data you want me to add? I just want to be sure that's what I should see. Is this going to add the calc_BAFN PID to the list of PIDs available under the PID tab in scan tool? Sorry if I'm being a P.I.T.A.

:D

[Blacky]

If you have not added any calculated PIDs to the cal_pids.txt then you can just cut and paste the entire text above into the matching place in the calc_pids.txt file.

If you have added calculated PIDs (although it sounds like you have not) then you need to insert the three lines into the file without distrubing the already defined calculated PIDs. You would also need to change the values of: CLC-00-100 and F100 so that they do not clash with any previously defined calculated PIDs.

Line 1, defines the UNITS for the PID.

BAFN None "%" "Base Airflow Numerator"

Line 2, defines the SLOT (Scaling, Limits, Offset and Transfer function). The "100" at the end must be unique across all SLOTs in the calc_pids.txt file AND it must not clash with any CLC-00-xxx SLOT entries in \Program files\EFILive\V7\Configuration\sae_generic.txt (see comments in that file for more info on calculated PIDs' SLOT numbers).


*CLC-00-100
BAFN 0.0 2.0 .2 "{GM.CYLAIR_DMA}/{GM.DYNCYLAIR_DMA}"

Line 3, defines the actual PID and the set of one or more units that it can be displayed as. In some calculated PIDs, that entry may contain multiple units to support metric/imperial - in this case it is not a PID that has metric/imperial alternatives so the UNITs entry is only BAFN.
The F100 value is a hexadecimal value that must be unique for each calculated PID. If one calculated PID relies on the value of another calculated PID (nested PIDs) then the PIDs are evaluated in the order defined by the F100 entry.


CALC.BAFN F100 CLC-00-100 BAFN Air "Base Airflow Numerator"

Regards
Paul

[VetPet]

Thanks Paul for the detailed info. I noticed that my user config folder does not contain an sae_generic.txt file. It has a folder named 'Notes', and one named 'Scripts'. The user config folder has the following files in it:

cal_adjust.txt
cal_link.txt
cal_setup.txt
calc_pids.txt
filters.txt
license.txt

I would like to post a screen shot of my new calc_pid for the BAFN for you to see but don't know how to do it. If you could give some direction on doing this it would be appreciated.

Regards,
Tony

[VetPet]

Paul, I figured out how to add the screen shot of my BAFN pid. Whoohoo!




# ================================================== ============================
# File details
# ------------
#
# This section defines various details about the file format.

*FILE

#Parameter Value Description
#---------- ---------------- ---------------------------------------------------
VERSION 7.1.1 File version
DECSEP . Decimal separator used in this file



# ================================================== ============================
# Units
# -------------------
# See sae_generic.txt for more information on the *UNITS section

*UNITS

#Code System Abbr Description
#-------- ---------- -------- -------------------------------------------------------------
BAFN None "%" "Base Airflow Numerator"


# ================================================== ============================
# Add slot definitions here
# --------------------------------
# See sae_generic.txt for more information on "SLOT" formats
#
#Units Low High Fmt Expression
#------------ ------------- ------------- ---- --------------------------------------------------------------
*CLC-00-100
BAFN 0.0 2.0 .2 "{GM.CYLAIR_DMA}/{GM.DYNCYLAIR_DMA}"


# ================================================== ============================
*PRN - Parameter Reference Numbers
# --------------------------------
# See sae_generic.txt for more information on the *PRN section
#
#Code PRN SLOT Units System Description
#------------------------- ---- ------------ ---------------- ---------------- ------------------------------------------
CALC.BAFN F100 CLC-00-100 BAFN Air "Base Airflow Numerator"

[VetPet]

Paul, I don't know why but the CALC.BAFN pid is not showing up in PID table in scan tool. I made sure I closed scan tool first and then reopened it after completing the calc_pid.txt. I looked over the file again to make sure I had the information in it properly and couldn't find anything wrong. Is it possible that there's another calc.pid file that has the same PID SLOT or PRN? How can I tell?

Thanks,
Tony

[VetPet]

Hi Paul,

Just wanted to say thanks for your help with this. I downloaded the new 7.3 version and created my CALC.BAFN PID in the calc_pid.txt file and it now appears in the PID tab. Your support is most appreciated.

Regards,
Tony
:D

[Blacky]

Hi Paul,

Just wanted to say thanks for your help with this. I downloaded the new 7.3 version and created my CALC.BAFN PID in the calc_pid.txt file and it now appears in the PID tab. Your support is most appreciated.

Regards,
Tony
:D

Good to see you know your way around EFILive now :)

I changed the tags in your post 2 above, from ... to
.... Using the code tags presents the text in green Courier font which makes it easier to read.

Regards
Paul

[VetPet]

Hey Paul, I had no problem downloading version 7.3 into my desktop PC but when I went to do it on my laptop I keep getting an error message telling me that the program can't find the "EFILive\Setup.exe file". My laptop uses Windows 2000 but my desktop uses Windows XP. I can see the Setup.exe file in the list of files shown when I unzip the new EFILive version on my laptop so I don't know why it's giving me that message. Any idea why this is happening?

Thanks,
Tony :)

[jfpilla]

I had the same problem with my laptop that has W2000. I used the Windows Installer to install. I got a 1309 message and kept clicking ignore and it installed. Don't know why, but it worked.

[Blacky]

Hey Paul, I had no problem downloading version 7.3 into my desktop PC but when I went to do it on my laptop I keep getting an error message telling me that the program can't find the "EFILive\Setup.exe file". My laptop uses Windows 2000 but my desktop uses Windows XP. I can see the Setup.exe file in the list of files shown when I unzip the new EFILive version on my laptop so I don't know why it's giving me that message. Any idea why this is happening?

Thanks,
Tony :)

Try running the Setup.exe file directly. That's all the Installer window does anyway.
Regards
Paul

[jfpilla]

Paul,
The exe. did what VetPet said. The windows installer did not. I could be crazy but I tried it numerous times. This was with my laptop that has W2000.
Joe

[Blacky]

Paul,
The exe. did what VetPet said. The windows installer did not. I could be crazy but I tried it numerous times. This was with my laptop that has W2000.
Joe

Do you mean EFILive_Installer.exe or EFILive\Setup.exe ?

EFILive_Installer.exe is the program that tries to launch EFILive\Setup.exe and is the only program that could give the error "Can't find EFILive\Setup.exe".

If you run EFILive\Setup.exe directly you should never see the error "Can't find EFILive\Setup.exe" because it will already be running.

Regards
Paul

[jfpilla]

Paul,
The exe. did what VetPet said. The windows installer did not. I could be crazy but I tried it numerous times. This was with my laptop that has W2000.
Joe

Do you mean EFILive_Installer.exe or EFILive\Setup.exe ?

EFILive_Installer.exe is the program that tries to launch EFILive\Setup.exe and is the only program that could give the error "Can't find EFILive\Setup.exe".

If you run EFILive\Setup.exe directly you should never see the error "Can't find EFILive\Setup.exe" because it will already be running.

Regards
Paul

Here's a screen shot.

[Blacky]

I don't think you can run Setup.exe directly from wihtin the zip file. You need to extract all files to a temporary folder first.

Regards
Paul

[jfpilla]

I don't think you can run Setup.exe directly from wihtin the zip file. You need to extract all files to a temporary folder first.

Regards
Paul

:oops: oops Live and learn. So all my setup issues were self inflicted.
Thanks
Joe

[Blacky]

:oops: oops Live and learn. So all my setup issues were self inflicted.
Thanks
Joe

Ahhh, some are probably not your fault... :? :?
Paul

[jfpilla]

:oops: oops Live and learn. So all my setup issues were self inflicted.
Thanks
Joe

Ahhh, some are probably not your fault... :? :?
Paul

You're too kind. :D

[jfpilla]

Self extracting executable for 324. Love it. :D

[Blacky]

Self extracting executable for 324. Love it. :D

originally I just zipped the V7.3.0 CD image and posted that.
I should have made a self extracting exe the first time :(
Paul

[joecar]

Self extracting executable for 324. Love it. :D
Yes, I love it so much I reinstall it once a day just to make me feel better.
:D

[VetPet]

I've done a lot of reading in the last while in several sites and have seen a lot of the 'history' behind the AutoVE tuning method and its evolution to where it is now. Since winter has arrived (officially got our first snowfall yesterday.....brrrrrr!!!!) I'll have a lot of time to digest all the pieces of the tuning puzzle so I'll be prepared when spring comes.

The question I have is, can you achieve a decent tune using the LTFT data to adjust your VE table without putting the PCM into SD mode? Assuming that your average LTFT logged is +10, you would want to multiply the VE table by 110% to increase the VE value which should decrease your LTFT's. You would repeat the process, if necessary, to try and get your LTFT's as close to zero, or somewhat negative, to prevent extra fuel from being added at WOT when the PE table is activated in order to prevent an overly rich condition. Then you could tune the PE table for WOT using a WBO2. At this point you have't touched any other tables and are only working with one change which, as a newbie, certainly makes life simpler.
I guess if you really wanted to be accurate you would change each cell in the VE table based on your LTFT cell reading for the same cell.

Would you want to adjust any other tables as well or would this be good enough? I don't have a big cam in my engine at this time (212/218) but I have another one that I'm planning to install (228/230). Would this make a difference on the method of tuning I would use?

Thanks for all the help.

:D

[deezel]

IMHO, the AutoVE method is the proper way to measure and map out the engine's air flow (VE table). With the mods you already have, another $300-400 for a WBO2 to tune it properly is easily worth it. I would recommend getting the WBO2 right away. It is nice to have the confidence of knowing your AFR is where you set it. Some run the WBO2 full time. I run mine for about a week at a time for tuning sessions - using the rear O2 port since the cleaned cats make the rear O2s useless.

If you still want to tune "old school" with the LTFTs, I would advise against modifying the VE table. I found that large VE changes are masked by the MAF in normal closed loop operation. The LTFTs will not change very much based on VE changes because the MAF reading is used for fueling. If you adjust the VE too far, you will get a MAF P0101 code for the predicted airflow not matching the MAF reading.
For old school tuning, start out using one of the following two options to adjust fueling: injector flow rate or MAF table. Either one is a global fueling adjustment. Once you get close, you can do a little fine tuning on the MAF table if you like. Once fuel trims are where you want (don't forget drive/learn time before evaluating trims), WOT fueling can be adjusted with PE table and the top end of the MAF calibration.

Happy tuning.

[VetPet]

Deezel, Thanks for the feedback. If I were to work with the MAF table for the time being, would logging actual and predicted MAF using these PIDs "GMCYLAIR_DMA" and "GMDYNCYLAIR_DMA in order to derive an airflow correction factor using the formula 'errorfactor = gmcylair_dma/gmdyncylair' be a more accurate way than using the average LTFT% to adjust the MAF table? Would this create a problem between the MAF and VE table resulting in an error code? I understand that the VE table is used in conjunction with the MAF during throttle transients and the VE table is also a 'sanity' check on the MAF airflow.

:D

[joecar]

Cylair and/or Dyncylair only works if the VE table is already dialled in;

the 3 things that effect LTFT's (disregarding PE) are:
a. IFR table
b. VE table
c. MAF table

So if a. and b. are correct, then b. can be used to derive c.

If you use c. to dial in LTFT's, then you won't be able to dial in c. to the correct values;

if b. is not correct, LTFT's may appear correct after tweaking c., but now neither b. nor c. are correct;

if a. is not correct, then life's hard until then ("tail chasing");

when a. b. c. are all correct, throttle response is amazingly good and LTFT's are resistant to external changes (change of weather)... :shock:

BTW: WBO2 shows true AFR (which helps to get VE dialled in) which NBO2 can't show.

[Blacky]

That sounded awfully like a high school boolean algebra class...
Paul

[VetPet]

That sounded awfully like a high school boolean algebra class...
Paul

Boy, and all along I thought boolean algebra was something Casper The Ghost learnt in shcool! :wink:

[joecar]

That sounded awfully like a high school boolean algebra class...
Paul

Boy, and all along I thought boolean algebra was something Casper The Ghost learnt in shcool! :wink:

ROFLOL... He he he... I'm sorry, I didn't mean for it to turn to jelly (my brain that is);
I didn't realize my writing had degenerated into algebra;
I can read/write algebra [or C or C++ or (gasp) Fortran or Ada or binary or hex] much better than English (or any thing else for that matter...)... :D

My apologies,
Joe
:D

[VetPet]

Joecar, glad to inject a little levity into the (Boolean) equation. I appreciate your application of logic to my question for those of us mathematically challenged. What's that saying, two wrongs don't make a right?

So, if I want to keep my MAF, I need to dial in the VE table first. But, I can't do that unless I use a WB in order to determine a correction factor for the VE table based on the actual AFR divided by the commanded AFR (the BEN factor table).

Once I have the VE table dialed in, I can then work on a correction factor for the MAF similar to what was done for the VE table. The factor will be a result of the actual MAF /calculated MAF. The data will be collected using two PID's (GMCYLAIR_DMA & GMDYNCYLAIR_DMA) and calculated with a new calc.pid using these two PID's as numerator and denominator.

The MAP to be created for the MAF correction factor will use the frequency values from the MAF tune table for the row values and the column values will be derived from the calc.pid created named calcbafn.pid (bafn = base airflow numerator). The bafn is the airflow error correction to be applied to the MAF table in order to get the MAF dialed in to the VE table. Same logic as applied to the VE table.

After this is done the LTFT's should be enabled again and the car driven around sufficiently to allow the LTFT's to be relearnt. Log the LTFT's and see where they are. If they are between +-5, we're good to go. If not, repeat the cycle until they are.

If any of the above is not correct let me know as I'm trying to write up the procedure in my own words.

:?: In the autoVE tutorial, the steps that direct you to disable the MAF, I was wondering why we can't set the MAF fail frequency to 0, especially those of us that have a 5 pin MAF. Does this not disable the MAF and put you inot open loop mode without disabling the IAT? Also, would leaving the MIL on let you know that you're in open loop when you start the car? You can always reset the DTC afterwards.

I think I'll stop talking now. Damn, I missed the hockey game again!

:D

[joecar]

VetPet,

Recalibrating MAF table:
You could also create a MAF table by using the GM.DYNAIR values directly
(since the VE is now dialled in, the dynair calculation is the correct air flow rate).

Disabling MAF:
I thought maf fail freq set to either 1 or 0 caused DTC to be thrown and MAF to be ignored;
yes, the DTC confirms SD mode;
physically unplugging the MAF ensures SD mode.

SD and OL:
Note that SD mode and Open Loop are two different things;
the Auto VE tute also directs you to disable LTFT corrections,
which is just another way of saying to disable Closed Loop mode;
you could leave the MIL on but this may mask other DTC's that may coccur.

Catch a rerun of the game...?

Regards,
Joe
:)

[VetPet]

Joecar, I'm hoping to catch a game tonight.

Is unplugging the MAF the only sure way to ensure that you're in SD mode? If I use scan to check the DTC's when I disable the MAF and only see the P0101, P0102 & P0103 codes set, can I assume the MAF is disabled and that I'm in SD mode? I guess the other thing I could is to remove the 3 wires for the MAF from the plug and leave the two for IAT in place. I'd need to get a wiring diagram for that.

:D

[joecar]

If I use scan to check the DTC's when I disable the MAF and only see the P0101, P0102 & P0103 codes set, can I assume the MAF is disabled and that I'm in SD mode?:D
It should be (it is on my 01 F-body), but it may not be, and unplugging the MAF guarantees that the MAF is ignored;
you'll know if it isn't because when you attempt use AutoTune to adjust the VE table the VE table will keep changing instead of converging with each successive attempt.


I guess the other thing I could is to remove the 3 wires for the MAF from the plug and leave the two for IAT in place. I'd need to get a wiring diagram for that.
If you search on LS1Tech you see that there some people do either of the following:
a. remove the pins from the 5-pin connector;
b. drill hole, insert grommet and IAT sensor, plug in 5-to-2 pin connector extension cord (fabricated or bought);
c. something else... (...what I forgot...)...
Yes, wire diagram does help alot.
What model and year do you have...?
I have the GM service CD covering 1997 thru 2003, I may be able to dig up the diagram after I get home tonight or something.

[VetPet]

Thanks Joecar, I have a 2001 C5 LS1. Appreciate the help.

:D

[ToplessTexan]

As an alternative to either removing pins from the 5 wire connector or integrating a separate 2-wire IAT, you might cobble up a little adapter (similar to what you'd need for option b) above) to connect only the pins of interest. If you're going to return to your current integrated MAF/IAT setup you'd like your mods supporting tuning to be as non-intrusive and easily reversible as possible.

[VetPet]

Thanks Texas, That would probably be best. It'd be more of a plug & play whenever I'm tuning in SD mode (which will probably be alot) come spring time. Damn, I wish I lived in the south!

8)

[kbracing96]

I believe that your MAF and the one on my truck are the same. If that's the case, then the tan and black wires next to each other on 1 end of the plug are the IAT wires. The other 3 wires are for the MAF. I cut the MAF wires about 3 inches back from the plug and crimped and soldered in a 3 wide weatherpack connector and so far, it has worked great.

[joecar]

Thanks Joecar, I have a 2001 C5 LS1. Appreciate the help.
:D
I didn't get a chance to pull up the diagram, but I'll send myself an email so I'll remember when I get home tonight.

[joecar]

2001 C5 MAF/IAT wire diagram.

[VetPet]

2001 C5 MAF/IAT wire diagram.

joecar, there doesn't seem to any attachment for the diagram. :)

[VetPet]

2001 C5 MAF/IAT wire diagram.

joecar, there doesn't seem to any attachment for the diagram. :)

Boy that's weird, the diagram wasn't there the first time I looked and now when I went back to the post there it was. My apologies joecar.

[Ira]

For what it's worth, you only need to cut one wire to disable the MAF, Pin E. That's the wire that caries the signal from the MAF to the ECM. Cut that and the MAF still works but the ECM can't see it. Works as well to cut C, D, and E but it's easier if you only have to reconnect 1 wire than 3 wires.

You could likely also get away with only cutting the 12V supply as pulling the fuse that cuts power to the MAF also causes a MAF error but I don't personally like leaving 12V wires hanging loose.

Ira

[joecar]

2001 C5 MAF/IAT wire diagram.

joecar, there doesn't seem to any attachment for the diagram. :)

Boy that's weird, the diagram wasn't there the first time I looked and now when I went back to the post there it was. My apologies joecar.
No worries mate, I get myself into weird holes all the time. :lol:

[joecar]

For what it's worth, you only need to cut one wire to disable the MAF, Pin E. That's the wire that caries the signal from the MAF to the ECM. Cut that and the MAF still works but the ECM can't see it. Works as well to cut C, D, and E but it's easier if you only have to reconnect 1 wire than 3 wires.

You could likely also get away with only cutting the 12V supply as pulling the fuse that cuts power to the MAF also causes a MAF error but I don't personally like leaving 12V wires hanging loose.

Ira
That's a very good idea, can just wire a SPST switch inline on the wire to pin E.

[dfe1]

I've been traveling quite a bit lately and haven't had a chance to post, so this is really out of sequence. Working with my 2001 C5, I've found that the VE table needs to be changed considerably when switching to speed density. I had my long term fuel trims really close when running the MAF and they were completely whacked when I switched to SD. I didn't disconnect any wires, just followed the tutorial, but it's clear that the engine is truly running in SD when I load that tune. If I switch back to the Mass Air tune, the long term trims are where they should be, but the VE tables for each tune are completely different. Alteriing VE values does have more impact on fuel flow than you might think, when running Mass Air.

With LS1 PCMs, what you see isn't necessarily what you get. Even when you're running in Mass Air mode, there's a lot of dependence on MAP-sensor based inputs, which means there is a lot of internal interpretation and referencing going on (and a lot of checks between predicted and actual values). As an example, the spark table is referenced to air flow, but if the the MAF is disconnected, air flow isn't being measured. That being the case, ignition timing should not function properly. It does, so obviously, the air flow values used in the timing tables are computed based on MAP and engine speed. A lot of this is probably tied into checks to ensure electronic throttle control is operating properly.

[Blacky]

It does, so obviously, the air flow values used in the timing tables are computed based on MAP and engine speed.

Correct, in SD mode the grams of air per cylinder are calculated as follows:
(as per the description on the VE table in the tuning tool).


The air mass per cylinder can be determined from the VE table using the following formula:
g/cyl = VE*MAP/charge temperature
Ve is in g*K/kPa,
MAP is in kPa,
charge temperature is in degrees Kelvin.

Actually two g/cyl values are calculated from the MAF and from the above equation all the time (SD mode or not). The two values are constantly compared to each other to verify that the MAF is working correctly.

In SD mode (i.e. if the PCM considers that the MAF has failed), then the g/cyl value derived from the MAF is ignored and only the g/cyl value derived from the VE table is used.

Regards
Paul

[VetPet]

Being a newbie here these are the kinds of topics that stretch my mind. Can you guys let me know if I've understood what's going on here correctly.

In true SD mode (running MAFless) you tuned your VE table with the MAF disconnected or removed. The tuning was done using a comparative measurement of the actual AFR from WB02 vs the predicted AFR calculated from the VE table values. The actual AFR divided by the predicted AFR gives you a factor used to multiply the VE table values to get them correct.

Now, if you're going to still use a MAF, then you need to perform one more step and recalibrate the MAF. This is done using the same methodology as the VE but, instead of measuring AFR you're measuring airflow, actual and predicted. The factor derived from these two is used to adjust the MAF table. Then you can plug your MAF back in, go into closed loop again and remeasure your LTFT's to see how well your VE and MAF are adjusted. Repeat the cycle as necessary per AutoTune.

What I'm gathering from this is that the MAF truly does need to be recalibrated for changes in the air intake tract such as cold air intake, better breathing heads, bigger camshaft, better exhaust even if you don't physically change its attributes. Otherwise, why would the VE tables have to be adjusted differently, depending on whether you run with or without a MAF?

Have I gotten this right or am I way off?

Thanks :D