HELP! Cant get to commanded AFR ratio under WOT, or LM2 issue?

2004 ctsv, 5.7, small smog legal cam, fast 92 mm ls6 intake, volant air intake, stock throttle body, injectors cleaned and flowed.

I went through and did VE and MAF tuning per tuning school books, everything came out cherry. Under WOT the it would run lean, can ping so bad you can hear it, never showing any knock retard though. So I move on to tuning at WOT for the MAF. I end up changing the curve so much and everytime its 20ish% off. The curve gets so high and now the car bogs. I have gone back to the point where VE and MAF are good several times and cant get to commanded in PE, or when I finally do the thing is running so fat. This one car is fighting me for the third time in 2 weeks. Same thing.


Now I am somewhat new and trying to learn so much its making me head hurt. I have street tuned this car and several others before. Again only this one fights me. We have since gotten a dyno and now I can tune on the dyno. I just had a car on the dyno, tuned through it no issues. Gets into commanded pe ratio no issues, wideband (lm2) reflects both on the screen and in scanner as the same. This car the, with the same offset settings as the last car, will show on the lm2 screen as one thing and in hptuners as something different. So I added a ground from the MPVI pro pin 5 to battery ground. Adjusted the offset to get them to match at idle and around 2k in third just holding steady. Under WOT ecm commands 12.3, lm2 screen shows around that, hptuners stays around 14.

So I fear Im fighting one issue because possible another one. Why is the lm2 not showing the same in both spots?


Attachment 53166VE and MAF tuning done
Attachment 53169Scan of above file running
Attachment 53167added more air via WOT AFR error
Attachment 53170scan of above file
Attachment 53171scan after adding lm2 ground

Ground offset is not constant. That's the mistake with the
scheme of baking in a correction factor to your wideband
transfer function. Ground offset comes from I*R drop (or
rise, in the case of ground) all along the signal chain, with
WBO2 heater power being the main issue in the meter
cabling, but also sheet metal ground currents between
the various "ground" points (OBDII port != cig lighter !=
PCM != firewall, when you get down to millivolts of
care-about).

And now, heater power changes a whole bunch with
the EGT in-the-moment (with some history / lag as well).
When you go WOT you supply most or all of the needed
heat from the gas stream, and need less from the meter
head. That right there makes your idle-range-derived
offset pretty completely bullshit for WOT, the fundamentals
have changed.

When in doubt, I'd trust the meter over the EIO because
EIO has a built in ground loop with the meter's signal return.

What you and just about everybody with an analog WBO2
meter really needs, for clean logging, is one of these:

Attachment 53178

{attached pic}. But I've never had the motivation to get
past my prototype (it works, and my hours are pretty much
accounted for). But if somebody with PCB talents and an
urge to do a Kickstarter raised their hand, I'd play along.
You could probably sell half a thousand of them, world-wide.
Woot, woot.

that board is holding you back. you can build smaller without it..

http://i1050.photobucket.com/albums/...autolamp21.jpg

picaxe driven, fully programmable universal auto lamp module.

Care to share details on what it will do? Rinse dishes and AFR feeds for me? How does one go about making such a device without having to study the theory and design of electrical components? Not that Im against learning...

I ended up grabbing another wideband that we have for our dyno what isnt feeding into hptuners, stuck it in the tail pipe and it is reading rather close to the display on the lm2. So trust the display ignore the reading in hptuners that I can offset.

Also I ended up changing the MAF table and giving it more air/fuel. Then also added timing, 2 degrees made the world of difference. Runs great and pulls hard, no pinging. If I add 2 degrees or remove 2 degrees, I get pinging. Managed to pick up almost 30hp from last week.

That board is an instrumentation amplifier (breaks the
ground loop, imposes the at-meter voltage to its own
ground, on the EIO input relative to -its- ground. The
rest of it is a poor-boy charge pump power supply that
makes the split rails the amplifier needs, from the
available 12V/GND (my earlier implementation used a
pair of 9V batteries for floating the amplifier, but I was
always finding I forgot to change them or bring spares).