with respect to AFR.

In particular, the AFR readings in N02,P04 (at idle) and N07,P17.

At idle i have the idle control and air pump disconnected (o2 feedback off), and it will not change much from high 12's. I'm having major issues getting the car to idle right, but that's another story.

At N07, P17 I get over 14 AFR (which scares the crap outta me), no matter how much fuel I dump in.

At the boost cell, the car is getting to the point that it's cutting out as if it's too rich. My guess is that I am getting voltage errors from my techedge 2.0 because the actual AFR is below 9.0, and its passing on a reading that is making it look to lean.

 

Most times the PFC is not running just off one cell. It uses the cell high lighted or in the log and surrounding cells. This is more evident in the P rows.

If P17 is 12 psi and P18 is 15 psi (based the the ABS value for the row) and you want to tune P17, you need to run about 13.5 psi to really be in the middle of P17 so that P16 and P18 aren't also used. If you run 12PSI, then you are getting more of P16 than P17 cell usage.

 

Also for the idle cells, if you have aftermarket injectors and have changed your lag settings to a positive number, this effectively adds in that amount of fuel, always. So for example, if you have 850 primaries, you might have to change your lag to negative numbers to lean out the idle. Just keep in mind that leans out the rest of your map too...

 

For the boost cell: 1) my max max boost is set at 13.5, right in the middle of that cell. 2) I had thought of neighboring cells effected the problem cell, and I did try to change the cells surrounding the one problem cell, but to no effect. It's like the PowerFC is ignoring my input right there, or more likely, I'm getting bad AFR readings there. But, I have had 60+ samples there, with little deviation.

For the idle cell: I think Chuck may have answered it in another recent post. Without O2 feedback on, it still will hunt, so it may be still affecting idle AFR. I will try turning it 02 F/B on and off in the Dataloggit. The only way to get it to stop hunting is to pull the ISC, and still the AFR are off. With the ISC plugged in, it will hunt, then settle down to the right RPM, but runs crappy, with about 5 inches less vacuum then i can get manually tunning it, and a too lean.

Thanks for the input, I'll keep at it.

 

A couple of questions/comments

N07, P17 is a hard cell to populate with many samples, are you reaching this cell under a WOT 3rd 4th or 5th gear run?

As you most likely know under WOT the first few cells go lean, an examples of this besides datalogs can be seen by looking at the AFRs on many dyno graphs.

After recalculating your injector base map, have you compared the value in N07, P17 to its surrounding cells? One would believe that N07,P17’s value would be larger than N06, P17 and N06, P17 and smaller than N08, P17and N07, P18.

I too, had difficulty adjusting idle AFRS; eventually with the O2 Feedback off I just added 10-20% fuel to verify it did indeed change.

 

Here is more details about the PFC O2 working even though it was turned off.
This week I was out returning my idle, cruise, to P10 rows due to my GT35R install.

I had re-initialized the PFC then loaded the new DAT. The only function I have turned on is the idle timing control. I initially used just the commander for ballpark while letting the new turbos heat up under idle and light cruising. Was cruising around in the high .70s to low .80s O2 voltages and it was smooth. All of a sudden it started acting lean and the O2 voltage dropped to .03 at 60MPH. Tapping the gas caused it to return to normal for a while, then it did it again. After stopping, I turned on the O2 for a few seconds, then tuned it off again. After that is stopped screwing up. To be sure I set the O2 parm down to 1 from 1.047. Hasnet acted up again.

I remember the first time I did a RECALC, it screwd up my O2 control and it took a long time to relearn.

 

WOT in 5th will let me spend some time in this cell, since its my max boost. Enough that I don't think its a momentary lean condition. This cell has more fuel (after recalc) than the surronding cells now that I keep dumping it in. And the car has started breaking up here like it did when I had less than 10 AFR in some cells at the bottom of the map when I first started on this new map. Ping numbers are perfectly fine here too.

This is the 3rd time I've done a tune to this car due to changing mods, and the last 2 times were easy. Last time was due to a new ported motor, and no problem. This time I cut out the cat and got an IC. Another change was upgrading the Techedge WB to 2.0, which is why I suspect the AFR number itself. I'm going to upgrade its firmware, and try again.

 

Thank you for the help. I think I have my issues solved for now.

The idle problem was due to the O2 control being stubborn it seems. When I turned the O2 FB down to 1.0, the idle started to behave itself, stayed around 12.8 AFR, and learned the idle point in about 2 min. Sometimes it for no reason starts to lean a bit, but a tap on the throttle chills it out. This is happening rarely.

A post on the Techedge Yahoo Group solved the boost AFR issue. Someone asked the perfect question of Peter for me. The wideband can read lean in an overly rich condition because of misfires. The unburned fuel stays in liquid droplets, and O2 is still around because they was no burning. The sensor sees the 02 and not the fuel, and reads lean.