VE tuning with HPT Wideband and Narrowband how to

[tici]

LS1Edit has a Open Loop Fuel Air Multiplier. It's a MAP vs temperature table.
Not sure if its IAT or engine coolant.
And... if it's open loop it's not the same as SD

I guess I'll have to repeat the VE calibration in summer and average it with the winter numbers.

Like the four seasons tires: good for every temperature but never perfect.

How many of you guys is done with the SD tune? Done, I mean it's DONE, FINISHED, EXACTLY AS YOU WANT, no more scanning, just drive and enjoy the ride?

[txhorns281]

SD mode is just not taking in account what the MAF reports (MAF fail mode)

So it's independent of Open or Closed Loop, you can still run SD in Open Loop. The only difference in open loop is there is no real time adjustability. The reason why our cars run open loop at all is cuz the O2s need a little time to heat up before properly (ha.... properly :) functioning, and once heated, Closed Loop can activate and control. In SD Mode, the PCM is biased completely towards using the VE calculation to determine airflow.

[tici]

Ok, but what is THE real advantage running SD?
Get raid of a (supposely) restricting MAF?
Or if you are sucking in much more air that what a MAF can handle?
Is it the only way to manage a wild cam?
I can't imagine that there are so many hidden HP... I can also confirm that the car responds a little better, but it doesn't make that huge difference.

Hope someone can explain this simple question - I'm still learning :P

[txhorns281]

Ok, but what is THE real advantage running SD?
Get raid of a (supposely) restricting MAF?
Or if you are sucking in much more air that what a MAF can handle?
Is it the only way to manage a wild cam?
I can't imagine that there are so many hidden HP... I can also confirm that the car responds a little better, but it doesn't make that huge difference.

Hope someone can explain this simple question - I'm still learning :P

I think the benefit to running SD is that you have less variables to clutter up and confuse your EFI computing. I mean the more things you throw at it, the more BS you come up with. SD is closer to real time, actual motor dynamics probably. The reason why we have all these sensors and crap is to try and account for as many driving conditions as possible. And they are pretty efficient at that from stock configuration from GM. BUt the more we mod, and the more we mess up the mechanical configuration of a motor, the more messed up the PCM controlling can get. So SD elminates some of a sensor bias and gets you closer to what theoretically the mechanical operation (the core if you will) of the motor is really asking for. That way you can give the motor what it's asking for from the EFI configuration and everything can be happy again. (More BS from my bag... lol)

The fact that you can remove the MAF is sort of an added bonus that removes the restriction in the intake. If you know what your motor likes airflow-wise, then you can recalibrate the MAF to "See it the same way" if you will and enable MAF operation again if you want. But the airflow your motor likes is always changing (mutlivariable function) and unpredictive, and the airflow that the MAF reports is a sort of single variable function (frequency). Often enough times these two functions do not yield the same answer and are in conflict with each other. The PCM uses a happy medium though or however it's configured to weight a decision. By removing the MAF it's end of discussion, VE wins, by recalibrating the MAF, it's getting the MAF and VE to agree more, but there's always the chance that b/c of load/weather/road conditions the two may not agree and the the PCM has to settle the conflict.

It's like going to court, when the prosecutor doesn't show up, the defendant walks, easy decision. If there's a trial, sometimes the innocent are convicted, sometimes the guilty are set free (haha.. OJ) If the PCM is coerced into making a bad decision, then you don't have a happy motor!

[cured5.7]

WOW TXhorns281, well said....

I know what you were saying but i had to read it twice just to make sure.. ;D

Regards Mark

[tici]

Nice explanation, thanx! It makes sense.
My 98 A4 doesn't like to run mafless and the only way to raid of this is to reprogram the PCM (Chris at HPTuners can do it). But then I also have to use his software + cable.
I'm pretty confortable with Edit and unless something goes bad (cable and so) I'll stay with that editor. And with my MAF.

At least now I know how it works and why I have this particular setup.

This thread is great! I learned a lot from you all. Thanks again

Stefano

[God_Forgives_IDont]

Well I have a question for ya'll "SD" guys out there. Why will my car not Idle with out the MAF hooked up and running? It Idled decently before I disabled it to tune the LTFTs and now it idles only about 20% of the time the rest of the time it just wants to fall on its face. If I could figure out how to make it Idle I would definatly think again about staying with the SD tune on mine.

[MNR-0]

Well I have a question for ya'll "SD" guys out there. Why will my car not Idle with out the MAF hooked up and running? It Idled decently before I disabled it to tune the LTFTs and now it idles only about 20% of the time the rest of the time it just wants to fall on its face. If I could figure out how to make it Idle I would definatly think again about staying with the SD tune on mine.

What TB are you running? Stock? If not, check the idler bypass valve. With aftermarket items they are mostly CAD designed with nerds who have no idea what these cars need in the real world. If it s small pinhole breather, there's your problem. Answer is to dremmel out the idler bypass valve to something of similar proportions to the stock TB.

If its a stock TB, you can try increasing base idle airflow and IAC.

[ixc]

Well I have a question for ya'll "SD" guys out there. Why will my car not Idle with out the MAF hooked up and running? It Idled decently before I disabled it to tune the LTFTs and now it idles only about 20% of the time the rest of the time it just wants to fall on its face. If I could figure out how to make it Idle I would definatly think again about staying with the SD tune on mine.

also since you have a 99 - you will have a secondary VE table that your car will run off of when the maf is unplugged. you will need to multiply the 400 800 1200 columns just like you did when you first were trying to get your car to idle after the cam.

i did mine by 70-80-90 i believe

[God_Forgives_IDont]

Well its a home ported and simi polished TB. I did fill in the holes with metal epoxy and drilled out the Fresh air port and the IAC. Matter of fact I went back and enlarged the holes at least once, don't remember the size I ended up with.

Thats a good point about upping the 400, 800, 1200 in the VE table but wouldn't that be taken car of with the part throttle tunning I'm currently working on?

Today for some odd reason my IDLE was surging bad for the first 30sec-1.5 minutes of IDLE. Not sure whats up with that but dang it's weird felt like the car wanted to just take off or die depending on the swing.

I've re-read this thread and instructions and I'm going back and re-tuning using the above narrow band method to try and get the LTFT to close to 0 again.

1 thing have have found in Texas with the extreme change in wether we get makes it so the LTFT can vary a bunch from day to day. So I'm going to take do it all in oneday and try and pick a day with good medium temp and low humidity.

Thanks for the Help guys! Your advice and guidense is always appreciated!

[marc_w]

Regarding setting MAF Fail frequency to 0 vs unplugging the MAF...

At least my vehicle, (and all drive by wires?), have the IAT sensor incorporated with the MAF.

I've been running on a MAFless tune for a while now, but with the MAF still plugged in and sitting there like it's working. The 'settitng MAF Fail frequency to 0' thing works just fine...

I'm pretty happy with my tune. STFT's and LTFT's aren't perfect, but they're pretty consistant and they're smooth. (0's down in the lower ranges, to -2's up higher). I don't think I'll ever be done with tuning it though. I can't leave anything alone for long.

[JimMueller]

So we can set ...

- Engine Diagnostics > General > MAF Sensor Fail Frequency = 0

...and disregard steps 1 & 2 in the original post, or do we still need to alter the DTC's?

What should my wideband be reporting with the SD tune loaded, but the MAF connected to log Frequency?

[ixc]

So we can set ...

- Engine Diagnostics > General > MAF Sensor Fail Frequency = 0

...and disregard steps 1 & 2 in the original post, or do we still need to alter the DTC's?

What should my wideband be reporting with the SD tune loaded, but the MAF connected to log Frequency?

your wideband readings will depend on how far off your VE table is. If you are logging the command AFR pid - it should be reading pretty close to 13.0 - mine reads 12.96. Just make sure that in your table display your FTC stays in 22.

[txhorns281]

Well its a home ported and simi polished TB. I did fill in the holes with metal epoxy and drilled out the Fresh air port and the IAC. Matter of fact I went back and enlarged the holes at least once, don't remember the size I ended up with.

Thats a good point about upping the 400, 800, 1200 in the VE table but wouldn't that be taken car of with the part throttle tunning I'm currently working on?

Today for some odd reason my IDLE was surging bad for the first 30sec-1.5 minutes of IDLE. Not sure whats up with that but dang it's weird felt like the car wanted to just take off or die depending on the swing.

I've re-read this thread and instructions and I'm going back and re-tuning using the above narrow band method to try and get the LTFT to close to 0 again.

1 thing have have found in Texas with the extreme change in wether we get makes it so the LTFT can vary a bunch from day to day. So I'm going to take do it all in oneday and try and pick a day with good medium temp and low humidity.

Thanks for the Help guys! Your advice and guidense is always appreciated!

yes, pick a medium type weather day to nail this down, and try to do it quick! The thing that sucks about narrowband tuning is that you have to drive around to let the trims relearn before you can get any really good data to continue tuning with. Widebands make VE tuning a one hour project! Also, keep in mind that your VE and SD airmass calcs are a little delayed compared to the MAF (although the MAF has more hesitancy to swing with weather changes) so your fueling around idle and low rpms will be very sensitive. Make sure the VE in those areas are relatively smooth and also the surrounding areas aren't causing any local effect. IE: you don't want your cells at idle to be in the trough of a valley, smooth out the VE to make it uniform!

[Jochen]

Hi,

wow, what a topic. I just read through all the posts . . . now i have kind of headache just kiddin !

I tried to understand the whole process, but i am a little bit confused. I did a long logging session yesterday, about 35 minutes with the MAF still working (i know i should have disconnected, will do one run without MAF tomorrow). I found most of my ltfts are between +13 and +20. I run a mostly Stock tuning (just a few alterations to spark done from a Hypertech).
I have a few mods which seems make the car run too lean (K&N gen II FIPK, Hich Flow MAF, Rando Tech. Cats and X-Pipe, B&B exhaust . . .). Those mods add more air that the stock parts do, so i guess the PCM tries to compensate.
My question:

.After my last mod (R/T cats and x-Pipe) i lost a few ponies on the dyno (about 10). i guess i am now running to lean under WOT. How can i find out (without WB o2) if i am running to lean under WOT, and how and where in the software i can set the correct AFR.
Where do i find the AFR the car runs on WOT ? during a logging session ?

I know, these questions might sound stupid to you guys, but i am new on PCM tuning . . .

Hope someone can help.

Thanks

Jochen

[checkmate]

Just to make sure:

When I set the MAF fail frequency to 0 should it set off the SES light for the MAF codes????

I didn't touch the codes and I didn't get a SES light so I ended up unplug the MAF just to make sure I was in speed density.

[God_Forgives_IDont]

You should check your DTC settings for 101, 102, and 103.
They should be set to:
Error Mode 1 - MIL on Second Error
SES light should be enabled - so you know you’re in SD mode for sure!
Someone please correct me if I'm wrong....

But, like you said just unplugging the MAF is a sure thing. I use the MAF Fail frequency = 0 method it's easier and you can log MAF Hz for other tuning with out the MAF effecting the SD mode on the pcm.

[checkmate]

You should check your DTC settings for 101, 102, and 103.
They should be set to:
Error Mode 1 - MIL on Second Error
SES light should be enabled - so you know you’re in SD mode for sure!
Someone please correct me if I'm wrong....

But, like you said just unplugging the MAF is a sure thing. I use the MAF Fail frequency = 0 method it's easier and you can log MAF Hz for other tuning with out the MAF effecting the SD mode on the pcm.

Hmm, I didn't touch the codes just because I wanted to make sure it fell into SD but I never got an SES light w/maf fail frequency = 0. I'll try it again today, hopefully it works because I should be able to wrap up the ve table today and move onto MAF tuning.

[BowlingSS]

I just about read all of this post. One question I have is should I wait for my wideband before doing the SD tuning?

BowlingSS

[SportSide_5.3]

I started to tune my truck by the dirrections written in this section of the forum I left the ltft's on and copied the high octane table to the low and followed all dirrections and tuned till my #'s were with in 10% then I figured I would move on to the next method and shut off the ltft's and just tune with the stft's when I got some data after driving around I now have numbers ranging anywhere from 0 up to -18 but mostly from around -11 to -18.
Should I continue this tune and do as it says to use these #'s in a 1:1 ratio in the VE table or could I have done something wrong? I have been reseting fuel trims as it says to. I have not turned off the ses light because I figure it doesn't matter to me I know why it's on. one last question is this a good way to tune then plug the MAF back in? or is this only for MAF less tuning?

I am having the exact same problem. ???

I got them babies @ 0-10% after one log/ve change and all of a sudden I'm seeing -20% :P

Has anyone else had this problem, or know what Jim and I are doing wrong?

Thanks,

Kyle