08 TBSS MAF tuning issues

[rDB]

We just put an attitude cam, 1.750 long tube headers and a 3200 stall in my friends 2008 TBSS and I am having some trouble tuning.
I am tuning by maf only with STFT's, SD is disabled along with DFCO and LTFT's. The histo is set up to log STFT bank1 against MAF airflow vs. output frequency, bank 1 and 2 keep going complete opposite of one another so I decided to tune by just bank 1. Will this work ok?
Lets say I am starting at 30% stft, when I mulitiply that cell by.995 it should lower it by .5% right? Well by the time I have knocked a few % out of that cell it will start running at -30%. I started out using the STFT sensor to tune and would highlight the entire histo then do a multiply by% half, that was just making it further off.

Basically it seems WAY more sensitive to adjustments then it should.
Would using LTFT's instead help? Or could there be a problem with an o2 sensor? In the scan the STFT jumps back to zero alot, that's just because I freaked out and reset the fuel trims.

it also has a 160 thermostat.

[mygm]

tunning LTFT is the fastest and easiest, the closer you get your LTFT to zero the STFT will follow on their own. After every change you make to your tune don't forget to reset your fuel trims

[rDB]

I'll try LTFT's to see if it works better but it still doesn't make any sense why it's acting the way it is. Whether using short terms or long terms, I should still be able to make small adjustments and get the trims at least close to 0%. It wont get any closer than + or - 10%.

[Xjas]

Your O2 sensors are not right, I had a quick look at the log and sometimes one 02 sensor reads 45mv and the other is 900mv, you have a faulty 02 sensor or wiring, exhaust header leak or some other issue that is making them act like that. You cant tune the car off your 02s untill they are reading correctly, you really should get a wide band anyway, cant tune OL with fuel trim without tonnes of experience.

[rDB]

Ahh I see what you mean, we didnt find any vacume leaks so we'll check the o2's next. Is the one running low mV the one not acting right? I guess we'll start with bank 2. Thanks for the help!

[eficalibrator]

Why not just use a wideband and do it right?

[rDB]

I'm only going by fuel trims for idle and cruising, but WOT I was going to do with a wideband, but I'm nowhere near that point. I hope I wasn't misleading enough to make you think I was trying to tune WOT by narrow band lol, thats why I spend more time reading than posting. Any recommendations for an LS2? And are you suggesting I tune the entire curve by wide band?

Edit: SO...if we have a wideband it would be easier to force open loop and tune that way over closed loop with fuel trims? I've never done this so off to reading i go lol. I have a AEM uego I could pull out of my mustang until my friend gets around to buying his own.

Edit2: BTW great book im reading through it again right now. It's been very helpfull

[gn2beatu]

Yes, it would be easier to tune OL with the wideband for all parts of tune, not just PE. If you have the wideband, give up on the narrow band tuning.

[rDB]

All right just to make sure I have this straight..

To hook up the aem wide band to the mpvi,
the white wire goes to slot 1
blue wire not used
red to switched 12v
black to ground
and slot 5 to ground. Can both of the ground wires just go straight to the negative terminal on the battery?
Will I need to check the pcm voltage vs. the wide band voltage to be sure they are the same or will it be good to go since its grounded to the battery?

To force open loop, under engine>fuel control> OL & CL> closed loop enable, set ECT vs. Startup ECT to 285 across the board.
Or should I just max it out? It will go to 306.
Is there anything else I need to do to force open loop?

Then to tune the MAF, log MAF frequency vs. AFR error% (in lambda).
Tuning virtual ve with the blue cat tool seems pretty straight forward but thats getting put off for now.
For logging lambda error% I made Custom PID using commanded AFR as the sensor in units as lambda, then my function string is [SENS.121]-[AUX.20005] for commanded - wide band afr.
Thanks.

[rDB]

Just trying to set up user defined parameters in the scanner right now. The function string for AFR error% will be
100*([USER.9006]-[SENS.121])/[SENS.121] correct?
The [USER.9006] is AEM wieband.

[Blades]

Remember to check the ground offset.. 5.00V reported from WBo2 may not be 5V at the end of the wire.. Alleviate this by focusing the 0-5V output over sane values - gaining resolution.. 10.5-17.5 is a nice start. What I mean by this is.... its better than 10.0-23AFR over 0-5V .. especially with an annoying ground offset that doesn't remain a constant.

We really need external digital input on the scanner software..