Runn

Set MAF fail frequency to 0.

WS6FirebirdTA00

iTrader: (33)

and you can turn the lights off in the trouble code section m just make sure the error is still reported for p101,102,103. as long as you DO NOT click on "no error reported" you will be good. yo do this so the car will fall in SD (however unplugging the maf is a shure thing ) you can unplug it and leave it in the intake line still

jub jub

My IAT sensor is built into the MAF. That's why I was asking.

Bink

I'm like RedHardSupra - My MAF is still there and I can scan it's reported airflow...But it's nonfunctional as far as the PCM is concerned. I have a 2001 Z06 - the MAF and the IAT are incorporated as a single unit. Leaving the MAF/IAT in place also feeds the IAT to the PCM...i.e. the IAT is functional and the PCM uses it's data. .

I would set both the MAF High Freqency Fail 1 {C2901} and the MAF High Freqency Fail Limit {C2902} to "1". This insures that it drops into SD at the 1st failure. By setting these to "1" the PCM will ignore the MAF and still recognize your IAT data.

FWIW.

Bink

Set both the MAF High Freqency Fail 1 {C2901} and the MAF High Freqency Fail Limit {C2902} to "1". This insures that it drops into SD at the 1st failure. By setting these to "1" the PCM will ignore the MAF and still recognize your IAT data.


Here, take a look at this EFILive VE Tutorial, page 6 " Set up Open Loop, Speed Density" -> http://www.efilive.com/doc/Tutorials...20Tutorial.pdf .

FWIW.

jub jub

Thanks guys for all the help! Switched to SD and zeroed out all the trims. The car is running much better it seems. Next step is to get a bung welded to the X pipe so I can use my LM-1. I've had it over a year and it's never been hooked up!

Bink

Any competent muffler shop can weld a bung. If you have Cats I'd put it ahead of the Cats. You'll be safer with the wideband

jub jub

Just thought I would post an update.

I was logging in the SD mode this weekend trying my best to fill as many L trim cells as possible. Got the VE table pretty much sorted out so that the L terms are between -5 to +5. All is good there. While I was logging, I noticed a huge difference between what the MAF was reporting and the Calculated air mass. (MAF still reporting even though I set the fail freq to 1) To see what affect this would have on the trims, I enabled the MAF and drove around a bit. As I suspected I triped lean codes on left and right banks. All cells were at +25. I guess the choice I have now is to try and bring MAF in line with the calculated flow but I really want to know what the AFR is before I know which way to go. I need to hurry and get that bung welded in.

From your guys experience, how do MAF and DYNAIR compare as far as accuracy?

WS6FirebirdTA00

iTrader: (33)

they should be the same, your maf is way out of calibration right now

jub jub

I hate it when it does that!

I like the way the car runs in SD mode so I'll probably just leave it that way for now.

WS6FirebirdTA00

iTrader: (33)

i would second that

soundengineer

iTrader: (16)

FWIW... I have never seen a stock MAF be correctly and accruately calibrated...
I have had to redo the table on every car I have tuned..even when the stock airbox is in place and the MAF has never been touched...
ANY modification you do to the car that could change the Airflow characteristics will change the MAF calibration accuracy...

jub jub

That was the whole point of this thread. In my mind, the MAF "should" report the airflow accurately. After all, that's it's job. So why doesn't it? If you make the engine breath better, it consumes more air, the MAF should measure it. It just doesn't make any sense to me!


*edit*
I was doing some research on this and came across two schools of thought on scaling the MAF. One school does each frequency individually and the other scales the whole table by a %. Is there any pros or cons on either one of these methods considering how the MAF is "flaky" in the first place?

jub jub

Wish I would have read this before I asked the question!

https://ls1tech.com/forums/advanced-engineering-tech/394925-how-maf-really-works.html

What the hell would we have to talk about, except the weather, if we didn't have the chance to repeat ourselves...for people like me!

soundengineer

iTrader: (16)

a couple of ways for you to "correct" your MAF
Log dynamic Airflow and plot it vs MAF frewuency(this is isally prety dam close because it uses your VE table to calculate it)
use Wideband AFR error %(dead on because you have a reference to what you want it to comand and what its actually commanding and you can do a little math to get it right)
LTFT+STFT (the best way if you plan on leaving your car in Closed Loop because it relys on the stock narrowband o2's and If you tune usung LTFT+STFT then you were tuning using the stock narrowband o2's anyways)

jub jub

I wanted to try that but I haven't been able to create a MAP in EFILive to log DYNAIR vs. MAF frequency. I have a MAP for DYNCYLAIR_DMA VS. MAF frequency that works but then I'd need to convert to total flow in G/sec and haven't got that far yet.

So anywhooo...here is my latest VE table running in SD. As you can see, it looks pretty choppy. What I find interesting in the high values in the mid rpm/low map range.

Anyone else with head/cam car like to post their VE table?

HumpinSS

iTrader: (1)

There is a calculated GM/sec pid if you are looking for it. I think you meant g/cyl in your post. Dynair is GM.DYNAIR and its located in the PID drop down list under Air you can use this to log against frequency if you want to convert the value to g/cyl the formula is as follows

gm/cyl= DYNAIR *15/RPM or you could log GM.DYNCYLAIR_DMA its the SD air pid located under tune. You will see what i mean when you look for it.

jub jub

Thanks Humpin. I think I tried that but when I ran my log file I didn't get the cells to show up. Then again, I probably didn't have that PID selected when I logged. Duhhh. I'm at work but I'll look at that when I get home tonight and try it again.