STOP the insanity... Final tune...
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STOP the insanity... Final tune... 
Sorry could not help myself...I need to put a nail in this coffin, move on with my life, some CLOSURE! You know what I am talking about...
Make these assumptions:
*SD/VE tune is spot on, +/- 2%, done with WB O2
*LG LT headers, notorious slow switching, LTFT accuracy suffers...
*Re-activate MAF (and everything else) and let LTFTs mature, say 200 hundred miles of varying conditions...
I start logging after the LTFTs have matured. These are long logs, 50 plus minutes. When I look at my LTFTs I see values of -2 thru -4 (rich) in most non WOT areas. In the same log when I look at my AFR% error vs. commanded I see values of 3 thru 4 (lean) in most non WOT areas... There are no weird spikes or anomalies in the data. I can repeat the experiment (and have) over and over.
Fly in my ointment: Obviously my front O2s disagree with my WB. I understand that a fare amount of this error is from the LG headers causing my O2s to switch SLOWLY and thus be less accurate.
What I am asking is given the amount of error mentioned above should I just call it a day and live with it???
just double check the wot and make sure everything feels good while cruising, your driving style is going to change when you stop logging, call it a day and enjoy the friggin car allready, I know where your comin from....
I would try doing a free-air calibration, and doing one last run. You want your VE table corrections to be within +/- .01 or +/-1%. Once you're there, try it one last time with the O2 sensors. If you monitor your AFR, and see that it doesn't go too lean, and your corrections are around +/-1 with the O2 sensors, I would call it great! If you're having driveability issues, then keep driving on, but it sounds to me that you've got it really well dialed in.
Best Luck!
Adrian
Best Luck!
Adrian
I agree, call it a day and move on with life. Atmospheric conditions vary from day to day. It sounds like you've done the right things. I still monitor my WBAFR all the time, but I haven't done any tuning in months. It is still of great interest to me and I'm glad for all the things that I've learned thus far. I plan to build a 408 within the next year with new heads. Then, I'll start tuning again.
Steve
Steve
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Originally Posted by HumpinSS
This tuning **** will make your head spin at times and I think it will contribute to the onset of OCD
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Verdad Gallardo Thread Starter
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Originally Posted by HumpinSS
This tuning **** will make your head spin at times and I think it will contribute to the onset of OCD
I just cannot get (after all tuning is said and done) my LTFTs (O2s) to agree with my AFR % Error (WB O2). The differential is about 6%. In other words when everything is hooked backup and turned back on my LTFTs trend towards -2 to -4 (non WOT) and my AFR % Error trends towards +2 to +3 (non WOT) per the same log.
I am almost positive it is from the extremely slowing switching front O2s. I get the slow switching error code every time I start the car. I tried the Denso sensors, they are crap worse then factory. I have also wrapped (ThermoTec) my LGs from top to bottom.... NO change...
Take Care,
Scott
You could mess with the NBO2 switch settings. There have been a few rare posts about changing this. Basically, I'd move the range the PCM considers stoich for the stock sensors a little bit at a time. You might be able to get it to stop pulling fuel at cruise.
~~~
Thinking about it....say your O2's generally switch from lean to rich at .500mV. If your fuel trims are going negative after you replace the WBO2 with the NBO2's, the PCM is getting feedback from the sensors saying you're above .500mV's more often then you are below .500mV's. It's then compensating by subtracting a little fuel making you lean in reality (assuming the WBO2 is right). I'd try adjusting the switch points up about .10~.15mV's across the board on the NBO2's and see if that helps any.
~~~
Your WOT should be perfectly fine though as long as the PCM isn't creating positive LTFT's and dumping in extra fuel.
~~~
Thinking about it....say your O2's generally switch from lean to rich at .500mV. If your fuel trims are going negative after you replace the WBO2 with the NBO2's, the PCM is getting feedback from the sensors saying you're above .500mV's more often then you are below .500mV's. It's then compensating by subtracting a little fuel making you lean in reality (assuming the WBO2 is right). I'd try adjusting the switch points up about .10~.15mV's across the board on the NBO2's and see if that helps any.
~~~
Your WOT should be perfectly fine though as long as the PCM isn't creating positive LTFT's and dumping in extra fuel.
Last edited by SSpdDmon; Mar 27, 2006 at 10:23 PM.
Originally Posted by SSpdDmon
You could mess with the NBO2 switch settings. There have been a few rare posts about changing this. Basically, I'd move the range the PCM considers stoich for the stock sensors a little bit at a time. You might be able to get it to stop pulling fuel at cruise.
~~~
Thinking about it....say your O2's generally switch from lean to rich at .500mV. If your fuel trims are going negative after you replace the WBO2 with the NBO2's, the PCM is getting feedback from the sensors saying you're above .500mV's more often then you are below .500mV's. It's then compensating by subtracting a little fuel making you lean in reality (assuming the WBO2 is right). I'd try adjusting the switch points up about .10~.15mV's across the board on the NBO2's and see if that helps any.
~~~
Your WOT should be perfectly fine though as long as the PCM isn't creating positive LTFT's and dumping in extra fuel.
~~~
Thinking about it....say your O2's generally switch from lean to rich at .500mV. If your fuel trims are going negative after you replace the WBO2 with the NBO2's, the PCM is getting feedback from the sensors saying you're above .500mV's more often then you are below .500mV's. It's then compensating by subtracting a little fuel making you lean in reality (assuming the WBO2 is right). I'd try adjusting the switch points up about .10~.15mV's across the board on the NBO2's and see if that helps any.
~~~
Your WOT should be perfectly fine though as long as the PCM isn't creating positive LTFT's and dumping in extra fuel.
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I did some adjustment to someone who had o2s installed post cat, way too far back. I did make a difference. But we will relocate anyway, as its not very good trying to dial them in there.
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Free Air ***UPDATE*** Free Air update...
I removed my WB sensor and just let it hang below the car. I tuned on the ignition only, started the scanner and watched my voltage meter and here is what I got:
4.630v....scanner
4.580v....Voltage meter
0.050v....Does not seem like much differnce...
I am surprised it did not read closer to 5.0v ???
I removed my WB sensor and just let it hang below the car. I tuned on the ignition only, started the scanner and watched my voltage meter and here is what I got:
4.630v....scanner
4.580v....Voltage meter
0.050v....Does not seem like much differnce...
I am surprised it did not read closer to 5.0v ???