VE tuning with HPT Wideband and Narrowband how to

[BLOWNZ06]

What would be different to use this method on a FI car?

My 1 Bar map is of course not seeing anything above 104 kpa, but if I sent that Open Loop table to AFR of 11.8 will it work correctly after I have overrun the MAF... or after you are past the MAF does it solely rely on the PE table?

If I sent eveyrthing above where I am seeing boost to 11.8 will if actually force it there is what I am concerned about? A NA car is of more fogiving of the A/F than a forced induction car would be.


EDIT: I guess my question is kind of irrelvant being that the MAP only goes to 1 BAR? But what if I have the 2 BAR.. then I can follow the same procedure, but using the 1.25 (~11.8) above 1 BAR?

[pknowles]

I just got my wideband in the mail and wanted to try setting my VE table using the Wideband method. Since the wideband tuning is done in open loop can I run in open loop and put my wideband in the bung for the passengers side front O2 with the passenger side front O2 disconnected? If open loop doesn't look at the O2 then it should work right. Obvously I can't do this in closed loop. I got a PLX M-300 and don't want to cut into my factory harness's for the simulated narrowband. I was thinking of dialing in my VE table like this and then work on PE while still in closed loop.

BTW I have the stock manifolds, cats, and exhaust on the car.

[ixc]

Ok the reasoning for the 13.0 is because it is a safe afr to opperate at all RPMs with. With that being said yes you will be logging points as high up as you can rev. The thing to keep in mind is that the 13.0 is only temporary, when you get to step 10 and above (changing the tables back to stock) the computer will be commanding stoich. 13.0 is only temporary while dialing in the VE table, because it is a good safe value. Also timing does effect fueling to some extent (ie...not enough timing will result in richer exhaust gases) and therefore it would not be advisable to mess with timing as it could throw off you results.

Thanks for your question I updated the procedure to help explain the reasoning for step #3

Matt

when i changed the multiplier to 1.13 - im showing a commanded AFR of 12.96. In your mind, is this close enough to 13.0 or should i change the multiplier to achieve 13.0?

also, disabling the maf codes are just for piece of mind i take it. if you have already passed emissions and the light doesnt bother you, it wont affect the process, correct?

and for anyone running 1.6 - 98 to 00 w/ secondary VE: do you "paste special" from the histogram straight to the secondary VE or do you have to paste to primary and then convert?

[txhorns281]

when i changed the multiplier to 1.13 - im showing a commanded AFR of 12.96. In your mind, is this close enough to 13.0 or should i change the multiplier to achieve 13.0?

also, disabling the maf codes are just for piece of mind i take it. if you have already passed emissions and the light doesnt bother you, it wont affect the process, correct?

and for anyone running 1.6 - 98 to 00 w/ secondary VE: do you "paste special" from the histogram straight to the secondary VE or do you have to paste to primary and then convert?

12.96 is close enough and the codes are just to keep the light off in case you might be worried about throwing another code. Having the light on all the time means you would not know if you were throwing another code, but if you're confident that your motor is all gravy, it's not a big deal. light on or off, as long as the MAF codes are thrown, you're in SD...

I would use the paste special for the MAP rows you need in the secondary as the computer most likely interpolates for the missing rows (creates averages b/w bounding rows) When you finally get your secondary VE in a good place, you can then do some interpolation yourself and derive averages for the missing rows in order to create a primary VE. This will ensure that your VE is smooth and also it will ensure that you are using log results from the secondary itself. Some people like to tune the Primary and then copy respective rows to the secondary when making adjustments... I just don't like doing that cuz the info you log is solely based on the secondary, so making changes to the primary seem a bit misleading... If the computer uses the secondary table, then you should tune the secondary. That's just my train of thought. Just cuz we don't see the missing rows in the secondary doesn't mean that the computer doesn't "create" them... Otherwise you wouldn't see a full histogram when logging off the secondary VE table.

I made a little secondary to primary VE calculator in excel that I posted here. You can use it if you want, it doesn't do anything magical except save the time to calculate. All you do is paste in the secondary and it pumps out a primary table. My secondary and primary look identical using that calculator! Hope this helps!

http://www.ls1tech.com/forums/showthread.php?t=257090

[ixc]

If you end up incorporating the "maf fail frequncy = 0"

make a note that this is under engine diagnostics -> general.

the whole time i thought i was in SD since my car was always in open loop, i wasnt, since i had just set the maf vs output frequency table to 0. it doesnt do the same thing

[txhorns281]

If you end up incorporating the "maf fail frequncy = 0"

make a note that this is under engine diagnostics -> general.

the whole time i thought i was in SD since my car was always in open loop, i wasnt, since i had just set the maf vs output frequency table to 0. it doesnt do the same thing

eh, having a hard time reading that one... The best way to ensure you're in SD mode is... TADA, unplug the MAF!!! Providing you didn't turn the DTCs off that need to set to throw the car into SD operation.

[BQuicksilver]

After re-reading this all again, it seems the only issues brought up but not covered too well are:

1) How to adjust the O2 switch points, and why?

2) If it is good policy/safe to to disable the DFCO when doing VE tuning with a WBO2? I think the answer to this one is "yes", but I'm not 100%

[txhorns281]

After re-reading this all again, it seems the only issues brought up but not covered too well are:

1) How to adjust the O2 switch points, and why?

2) If it is good policy/safe to to disable the DFCO when doing VE tuning with a WBO2? I think the answer to this one is "yes", but I'm not 100%

#1) O2s suck so during closed loop operation (especially with headers) they may not be reading accurate AFRs. You can tell the O2s what to consider rich/lean which should result in less false trimming.

IE. I tuned out my VE via wideband, but always get this rich triming (negatives) around idle/low MAP/low RPM. whatever MV my O2s are seeing in comparison to my rich/lean switch point is greater:

MV read by O2s > Rich/Lean MV switch point

So in my case I may want to increase my Rich/Lean switch point (at whatever airflow modes I'm having trimming problems) so that the MV read by the O2s are not considered "so" rich. The way you know what Airflow Mode you are in, is find out what MAF frequencies cause trimming problems for you, take the appropriate airflow at those frequencies (g/sec) and in the Airflow Mode table it lists airflow (g/sec) as your axis, and the corresponding mode.

The computer will see this as less rich than what follows:

600 mv read > Rich/Lean switch point 525 mv
600 mv read > Rich/Lean switch point 450 mv

But this only seems to effect closed loop operation, for me, my rich stuff is going on in open loop as well... but just to paint the picture for ya! (If i did it correctly... :-[)
#2) YES, although I didn't have to since I never got the lean readings on throttle let off like many other people ???

[AnotherUser]

The best way to ensure you're in SD mode is... TADA, unplug the MAF!!!

I have been saying that forever.

You are wrong about the O2 switching point changes only changing closed loop. Make sure you disable proportional idle, or you will really be all screwed up. What you will find after you change your swicthing points, is that all your low rpm trims are going to start going negative as it tries to pull fuel. Your PCM will listen, believe me. Then you will have to adjust your VE table again. Once that is done, those VE values will affect your open loop operation as well. Those closed loop tables are just a multiplier that is affected by the VE values just like closed loop. I am thinking we may need to go lower on the mv readings on the O2 sensors for airflow modes 0-12. My first test is probably going to be 367mv (or whatever my 0 value was...I think that was it). As soon as all this blasted snow and ice melts...

[txhorns281]

I have been saying that forever.

You are wrong about the O2 switching point changes only changing closed loop. Make sure you disable proportional idle, or you will really be all screwed up. What you will find after you change your swicthing points, is that all your low rpm trims are going to start going negative as it tries to pull fuel. Your PCM will listen, believe me. Then you will have to adjust your VE table again. Once that is done, those VE values will affect your open loop operation as well. Those closed loop tables are just a multiplier that is affected by the VE values just like closed loop. I am thinking we may need to go lower on the mv readings on the O2 sensors for airflow modes 0-12. My first test is probably going to be 367mv (or whatever my 0 value was...I think that was it). As soon as all this blasted snow and ice melts...

very good to know! As I tried to rationalize it, you would think it went the other way. i think you posted something about it on LS1Tech huh? lol Man... this is like America's Most Wanted for finding the "who dunnit" on the screwy tuning...

[tici]

Have you guys seen VE differences depending on the air temperature?
Two weeks ago I managed to have all RPM vs MAP cells between -1 and 0%, then I reconnected the MAF and made a new Hz vs G/sec curve. Look perfect now...

Today I checked the VE stuff again (just to see) and it's all off by -4 /+1%.

The only thing that changed was the air temparature: 10F lower (!!!)

[corpsvette]

Personally, I am somewhat puzzled and frustrated. I have gotten my VE table nailed several times and then a slight temperature change occurs and my AFR jumps drastically from one direction to the other. I try to stick with a standard temp but I haven't won the lotto yet which means I still have to work, take kids to soccer, accomplish wife duties, etc, etc (single guys take note and stay single). Anywho, so yes, I have the same issues you are dealing with. Mine have even been affected by the level of gas in the tank. If I have just filled the tank, I have to drive a few days before attempting to log. Sometimes I wonder if my WB is going haywire but when I calibrate it, it always reads dead on at 20.9 for free air. Got me on what a solution might be. Good luck.

Jim K.

[pknowles]

I've found that tempurature affects the trims around idle the most. 2-3 weeks ago I logged in 60 degree F temps and then 2 days later in 20 degree F temps. Around idle the LTFT cells where -4 more in 20F then 60F, all of the other cells changed by -1 to -2.

[tici]

I've found that tempurature affects the trims around idle the most. 2-3 weeks ago I logged in 60 degree F temps and then 2 days later in 20 degree F temps. Around idle the LTFT cells where -4 more in 20F then 60F, all of the other cells changed by -1 to -2.

Exactly the same change I noticed!

I don't find any temperature related fuel correction in Edit, is there any in HPTuners?

[txhorns281]

What's interesting is here's the VE calculation goes as follows (taken from another thread)

VE = ((massflow * IAT / (MAP * RPM * Displacement))

Here goes an attempt: Looking at the equation, when IATs decrease the PCM calculated/expected VE decreases, while the actual VE value in your table stays constant. And I think the dynamic massflow density increases too when the air is colder, so that also increases the numerator. So if the motor needs/calculates less VE (due to lower temps) the value you have in your VE table is then more than necessary and would create a slight rich condition when the table is referenced. I guess this is why people say you run richer when it's colder than the temp you tuned at. That would explain the larger swing in trims when it got colder. Anyone wanna backup the BS that just came outta my mouth... :P

Doesn't the MAF play a small part in correcting for weather conditions?

[tici]

I think it makes sense, it just would be nice to be able to tune the way the PCM uses the IAT signal.

Also what you say about the MAF makes sense to me. I noticed less up-and-down in the STFT when the MAF is connected. Like if the MAF was smoothing the variations that a SD tune can't handle.

I think that the combination MAF + VE is a good thing and I wonder why so many people are trying to run MAFless. Is it really so much better? In my case it responds a little better, but just a little. And if I have to have a weater related tune... no thanks!

I start to think that the VE table has to be there just as a reference during fast load changes. It has to be correct but not super-precise and should be good for any weater situation.
That's why I leave the IFR alone, I try to keep an all-year-VE table and tune the cells using the MAF table.

But this can also be a bunch of BS...

[txhorns281]

You could alway make seasonal tunes if your climate varies a great deal... In TX, it get's kinda cold (30s-50s) then within a month it can turn right on it's head and get into the upper 90s-100s!

[tici]

5 to 90F here...
Are you suggesting a tune for each season? :P

How was the program of the older no-MAF GM-cars? They were all SD. All always a little wrong or was it a total different kind of program?

[Magic_Chicken]

There are some Cylinder Charge Temperature settings in 1.6 that allow you to make adjustments for varying IAT and ECT temps for SD tuning.

Engine>Airflow>General

check it out, might be what you are looking for

[txhorns281]

There are some Cylinder Charge Temperature settings in 1.6 that allow you to make adjustments for varying IAT and ECT temps for SD tuning.

Engine>Airflow>General

check it out, might be what you are looking for

I only have Charge Temp Bias. So a value of 1 will ignore IAT? Would having the airflow calc based off ECT primarily be better since there's not at much variance as IAT? ???