Wierd O2's at WOT only???

[turbolarry]

I'm tuning a 2g that is giving me a hard time, but at WOT only.
It's well modded; intake, 20g, FMIC, 720cc's, 255fp, AFPR @ 43psi/vacuum off, full 3 inch exhaust, S-AFC, BPR7ES @.26, stock internals, stock cams... vacuum hoses all check out, idels fine and great at partial throttle. The fuel trims are near perfect at +/- 3% at 1K, 2K, 3K, and 4K and carried it up from there. The O2's cycle regularly like they should within the normal range and on 91 octane.
Now I've moved on to WOT with the boost set at 1.2 Bar/17.4 psi. I carried over my Low throttle settings to start with, logged a run, and they were lean. I was getting .85-.87 volts, and it bogged. OK, but I trust my logger, so I richin some points up to get close to .94-.95 volts. Go to log a run (flat road, 3rd gear, WOT) and it boggs even worse. So bad I just stopped at 5K. I look at what the logger picked up and the O2's were at .89-.91 volts. WTF That should be lean for a 2g. I put the AFC settings back to where I started and tried it again. Still bogged, but not as bad. I took a chance, leaned it out a little more, did a run and it felt better only bogging a little after 6k. I leaned out a little more at that spot, ran, only a slight bog again, but it felt way better. However, the O2's are showing way lean at .85-87 volts, peaking at .89 volts, but the timing is not that bad and the EGT's are higher than I like too (880*-890*C), just a hair shy of 900*C.
Has anyone seen anything like this before? What should I trust, O2's or the timing? Bad O2 sensor? Is there something I'm missing? Should I just accept that this is how the car is and tune for .85 volts? What else should I look at?
Here's my last log at WOT;

2996 .79 15
3112 .79 12
3244 .79 10
3380 .81 8
3540 .81 5
3664 .81 6
3828 .81 6
4004 .81 7
4160 .83 8
4324 .83 9
4500 .83 8 Knock, but only pulls 1*
4680 .85 9
4764 .85 9
4904 .85 10
5052 .85 10
5188 .85 11
5288 .85 12
5408 .85 11 Knock, but only pulls 1*
5500 .87 13
5620 .87 13
5704 .87 14
5780 .87 14
5944 .87 16
5952 .87 16
6036 .87 17
6232 .87 18 ***
6180 .87 17 Here's the bog -100 RPMS
6336 .85 17 ***
6388 .87 17
6468 .87 18
6540 .87 18
6572 .81 19
6608 .89 18 ***
6640 .89 18 Slight knock here???
6632 .87 18 ***
6748 .89 18
6940 .89 20

This is not my car, but a buddies I've been driving for 2 weeks. I've had a 2g for a while and tuned other 2g's and never seen anything like this. I talked to him toady and he told me that it is the original O2 sensor but would it be that far off?

 

[spyderturbo007]

A couple of things.....

You really can't tune for O2 voltage, as it's pretty much worthless. But you can use it as an "vauge estimation" of AFR. Your's obviously looks lean, but the timing looks OK, but it is on the low side.

With 720cc injectors, you should be dropping to about 10 degrees and climbing to 20+ degrees, so there is something going on. Also, you can't assume that a timing pull of 1 degree is knock. The ECU will pull timing for other reasons, such as IAT over 84 degrees, coolant temp over 210 (If I remeber correctly) and sometimes you have just been dropped into a lower timing map based on your airflow.

I did notice that your rpms dropped at the moment you mention the bog. Replacing your O2 sensor will not fix the problem, as the ECU could care less about O2 voltage durning WOT.

Do me a favor and post up your SAFC-II settings, such as TPS trigger points, Ne points and corresponding correction factors (both Hi and Lo maps) and if you get a chance, make another pull while adding airflow to your log.

A couple of other things.....did you do a leak check? Did you verify that the TPS is at ~100% at WOT?

 

[turbolarry]

... you can use it as an "vauge estimation" of AFR. Your's obviously looks lean, but the timing looks OK, but it is on the low side.

That's what I'm saying, but it's not even in the ballpark. It looks lean, but it's doesn't act lean. If I try to richen it up it boggs from excess fuel.

I did notice that your rpms dropped at the moment you mention the bog. Replacing your O2 sensor will not fix the problem, as the ECU could care less about O2 voltage durning WOT.

I'm going to lean it out a little more there and see what happens. I talked to RRE about the problem too and they said to go by the O2's as a last resort. Wideband first, then timing & EGT's, then O2 voltage.

Do me a favor and post up your SAFC-II settings, such as TPS trigger points, Ne points and corresponding correction factors (both Hi and Lo maps) and if you get a chance, make another pull while adding airflow to your log.

Throttle points: Lo = 25% Hi = 80%
Ne points: 1K, 2K, 3K, 4K, 5K, 5.5K, 6K, 7K
Low Correction;
1K= -3%
2K = -8%
3K = -15%
4K = -14%
5K = -14%
5.5K = -14%
6K = -14%
7K = -14%
High Correction
1K = -3%
2K = -8%
3K = -8%
4K = -12%
5K = -14%
5.5K = -14%
6K = -17%
7K = -18%

I'll log a run tonight, including airflow. Should I just go ahead and omit O2 voltage since it's so far off?

A couple of other things.....did you do a leak check? Did you verify that the TPS is at ~100% at WOT?

No a leak check hasn't been done and I know I need to adjust the TPS; it's showing 97% with not floor mat.

 

[turbolarry]

How wierd is this???
I continued to lean it out based on the timing and EGT's. After I got to a certain point, all of a sudden, the O2 voltage started reading normal .95-.97 volts.WTF
It was so rich that the O2's showed lean?

Here's the last log I got;

2988 .91 17
3112 .91 15
3240 .91 12
3380 .91 11
3528 .93 9
3664 .93 7
3848 .93 7
4024 .93 9
4252 .93 9
4408 .93 9
4596 .93 9
4812 .93 10
5004 .93 10
5172 .93 11
5348 .93 12
5532 .93 13
5680 .93 14
5824 .93 16
6016 .93 17
6336 .95 17
6464 .95 17
6608 .95 17
6700 .95 18
6832 .95 18
6940 .95 19
7020 .95 19

All of a sudden the O2's were fine.WTF

 

[spyderturbo007]

That's funky that the O2's are returning to normal. WTF

Normally on a pig rich tune, the O2 voltage will peg around 1 volt. Wow, you learn something new every day.

The log looks much better. -14% is really rich for 720cc injectors, given that they are almost 38% bigger than stock.

There is no need to adjust your TPS, as anything over ~90% the ECU regards as WOT anyway. I would, however, suggest a leak test.

Where did you end up with your Ne Point Corrections? Your timing still looks a little low for that size injectors.

 

[turbolarry]

I don't have the car any more, I had to give the car back to the owner. He's going to to the leak test, swap in a new boost controller, and throw in a 1g TB/adjust TPS and cable.
I believe the Ne points from the last log were around -23/-24 percent from 4K to 7K. I'll get the car back for tuning in a couple of weeks.

 

[spyderturbo007]

I don't have the car any more, I had to give the car back to the owner.

Oh. Well, does that mean that the pretty red EVO in the picture is yours?

If so, it must suck to get stuck with an EVO.


Let us know when you get it back.

 

[dets]

I think you have reached the limitations of the narrow band sensor you are using.


Narrow band 02 really lose all types of logging capabilities when they are pushed and you should not tune with a NB 02 under any circumstances.


Personally, i use the innovative WB kit. I can hook it up to my labtop independately and log with it or i can leave hooked up to my SEM.

 

[CanadianTSi]

-24 should still be REALLY rich with 720's ?

I'm at -38 up top with 650's.