Data Logs

[Danny Cabral]

Second, is pulled plugs after 50 miles of driving, and they are powder white, but the Learn Table looks like it's -20 to -30% in all areas. Does this mean Target A/F Ratio Table is too lean?

Yes, that looks like you have a failing WBO2 sensor.
http://forums.holley.com/showthread....ension-Harness (WBO2 Sensor Info - Read "Wideband O2 Sensor Notes")
http://forums.holley.com/showthread....7571#post27571 (Additional Troubleshooting Information)
I would temporarily disabled Closed Loop (to ignore the WBO2 sensor), and clear the Learn Table (because it may very well be corrupted from it). The Learn Table must be cleared, or you must load the last "known to be good" Global Folder. If you have a "known to be good" Global Folder (Learn has self-tuned the Fuel Table), you can run the engine in Open Loop mode, until the replacement WBO2 sensor arrives. Also, ensure you're using the latest EFI software & ECU firmware (Link); it has "Oxygen Sensor Control Updates" (Link - HEFI_1589.eep).

• If you suspect a failed WBO2 sensor, and your Fuel Table is well tuned, you can disable Closed Loop (in System Parameters), and the engine should run fine until a replacement WBO2 sensor arrives. You can do this to determine if the WBO2 sensor is at fault (at least at idle), because in Open Loop mode, the ECU ignores the WBO2 sensor. So if the engine starts running good in Open Loop mode, you've found the problem. Just ensure that you don't disable Closed Loop mode while the Learn Table is corrupted from a failed WBO2 sensor. Clear the Learn Table (if the percentages are erroneous from their nominal values), or load the last "known to be good" Global Folder. Also, if the ECU detects a WBO2 failure, it will go into Open Loop mode. • If you experience a failed WBO2 sensor on a fairly new EFI installation (low miles), ensure the current WBO2 sensor location isn't causing damage by exhaust condensation thermally shocking the sensor at startup and/or during the warmup period. If you suspect it is, install a sensor bung at a better location, use a taller O2 sensor bung or use an Innovate Motorsports HBX-1 to move the sensor probe out of the direct exhaust stream. I've been successfully using HBX-1 Heat-Sink Bung Extenders for many years. ↑ This is referring to the "wet" gases flowing through the exhaust system while the engine is cold. On most vehicles, you can literally see water spitting out of the tailpipe(s). It's imperative to prevent this water from contacting the WBO2 sensor, because it will thermally shock the heated sensor. OEM engineers go to great lengths to locate the WBO2 at its optimum location. Anyway, a poor sensor location can actually blow water directly at the sensor probe. Look at the routing direction (angle) of the exhaust pipe just ahead of the sensor. Does it "direct" the water right at the sensor or away from it?

[S2H]

Briefly turn off the Closed Loop & Learning, and do a short datalog.
See if you see the same jumps in signal.
Then swap the WBO2 sensors from one side to the other, and see if it follows.
This will tell us if it's a problem with misfires/exhaust leak/something mechanical, or a problem with the sensors.

[vette09]

Here's the Open Loop log. Couldn't find any exhaust leaks, everything seems tight.
Forgot to clear the Learn Table for the Open Loop datalog. Datalog with Learned cleared.

[Danny Cabral]

Forgot to clear the Learn Table for the Open Loop datalog. Datalog with Learned cleared.

That's a lot better.

[vette09]

Left is starting to get noisy at the end. Does this mean it was so lean it was misfiring? It definitely ran the smoothest yet in Open Loop, even being rich on fuel.

[Danny Cabral]

Left is starting to get noisy at the end. Does this mean it was so lean it was misfiring?

You have dual WBO2 sensors (Dominator ECU), right? If so, they both provide ECU feedback to the same Fuel Tables.
I suspect a failing WBO2 sensor. Swap the WBO2 sensors from side-to-side, as S2H mentioned in post #12.

[vette09]

Datalog with the sensors swapped, looks like it is the WBO2 sensor!

[vette09]

Installed two new NTK 554-100 WBO2 sensors, to replace the Bosch 554-101 units. Huge difference!

[Danny Cabral]

Installed two new NTK 554-100 WBO2 sensors, to replace the Bosch 554-101 units. Huge difference!

Yep, that looks good. I knew it was a failing WBO2 sensor. You'll like the NTK WBO2 sensors.