O2 wavy up and down then smooth

[gmachala404]

After the car warms up and goes into closed loop, the O2 sensor go from lean to rich like a sine wave. I attached images of what I mean. It lasts for a few
seconds then smooths out. Is there a way to tune that out or is it a physical problem?

[Xjas]

Looks like its going into PE maybe, tune file?

[edcmat-l1]

They're supposed to oscillate like a sine wave. That is proper O2/fuel trim function. It should not flat line at zero unless you're in PE, or open loop. If it is flat lining at part throttle, something is wrong.

Attach a data log and tune.

[gmachala404]

Here is my tune and a log file

[edcmat-l1]

Fuel/Power Enrichment/PE throttle pedal. 1000 and 1500 cells are zero. Set them to 18 or 19. That should keep it from going back into open loop at part throttle.

Also, why is the PE table setup the way that it is? That's not right at all.

[gmachala404]

Fuel/Power Enrichment/PE throttle pedal. 1000 and 1500 cells are zero. Set them to 18 or 19. That should keep it from going back into open loop at part throttle.

Also, why is the PE table setup the way that it is? That's not right at all.

The PE table is what Speartech sent with the pcm. I have no idea. When I first Got the computer and harness it wouldn't even crank So I have been spending months trying to sort everything on my own even tried a Texas speed mail order tune since i am using their 225/230 cam and it still barely ran. So 6 months ago I got the tuning software and started researching and learning. So far I got the idle tuning done, I have gotten the VE->EQ stuff done and tuned the MAF and transmission (ACE Racing Trans with vac modulator). I have just started logging WOT tuning. Any idea what the PE table should look like or what PE table I should start with?

LS3 Chevelle 225/230 TSP Cam 1-7/8" SW longtubes & 3" musclecar exhaust.

[edcmat-l1]

Personally, I would set the PE to 1.17 across the board, then tune the MAF to that.

[gmachala404]

Thanks for the helpful tips. I plugged in values for the PE enable TPS and
the O2 sensors are not flat lining anymore at part throttle cruise. If I enter
1.17 across the board on the PE table should I then be tuning the MAF vs Output Frequency for WOT AFR? I thought PE was used to tweak the WOT'
AFR.

[edcmat-l1]

Thanks for the helpful tips. I plugged in values for the PE enable TPS and
the O2 sensors are not flat lining anymore at part throttle cruise. If I enter
1.17 across the board on the PE table should I then be tuning the MAF vs Output Frequency for WOT AFR? I thought PE was used to tweak the WOT'
AFR.

The PE is your commanded A/F at WOT. So 14.63/1.17=12.5:1. That's about what I would shoot for in that combo. Set the PE to this, and then dial in the MAF in the WOT area, to get it to that.

[gmachala404]

Awesome information. Car is really running good now the O2 readings look like nice sinewaves and it is much smoother running. LTFT are steady now around 2-3% working on wot MAF tuning now. Its running really strong now. Thanks for the explanation. PE table makes more sense now.