Need ideas on why I'm going LEAN

[Department Of Boost]

How about the "brushes" in the throttle?

 

[Embalmer]

Since I'm logging with Innovate, I can't figure out how to get a CSV log. So, here is the best I can do as far as a graph is concerned. Pink is air fuel, spiking to 21 then 22. The brown and blue are O2 sensor voltages. Why they spike down when my air fuel also spikes is the mystery I think. Black is RPM and dark blue if MAF. The two lines across the middle are short term fuel trims.

And a compressed version:

Any ideas?

 

[TheKurgan]

Why are the fuel trims all over the place ? Those should be as close to 1 as possible right ? Looks to be something with the fuel pump or tune.

 

[Embalmer]

Why are the fuel trims all over the place ? Those should be as close to 1 as possible right ? Looks to be something with the fuel pump or tune.

The trims are the two lines straight across the middle, The lines going down are the O2 sensor voltages.

Here's another snip from a different log with more parameters:

 

[TheKurgan]

The trims are the two lines straight across the middle, The lines going down are the O2 sensor voltages.

Here's another snip from a different log with more parameters:

I can't really see that graph too good but I was referring to the video you made with your ipad.

 

[Embalmer]

I can't really see that graph too good but I was referring to the video you made with your ipad.

I was wondering similar thoughts. I think the O2 sensor voltages are just responding to the spike to lean. But what is causing that spike is my issue. I lifted this off tricktuners.com website about fuel trims:

These ratios represent pounds of air needed for each pound of fuel to run at the stoichiometric ratio. When the air fuel ratio starts to go lean (higher than stoichiometric) the ecu will readjust the fueling (by injector pulse width) to correct the lean condition and bring the combustion back to lambda 1. This is a constant feedback loop (or a closed loop) and happens fairly quickly so it can alter the fueling over then next few engine cycles. The amount of correction can be viewed as the short term fuel trims (STFT) with an OBDII datalogger. The STFT can be displayed in different forms sometimes. With SCT software the value will be in the form of 0.75 to 1.25 indicating a -25% to +25%, while most other dataloggers will display the actual percent. If the STFT value is negative (or less than 1) the ecu is adding fuel to correct for a lean condition. These STFTs can be viewed in real time with a datalogger and are in effect anytime the vehicle is in closed loop. After a certain period of time, if the STFT is off, the value will be stored in the ECU as the long term fuel trim (LTFT). The purpose of the LTFT is to bring the STFT back around 0% so that it can still adjust +25%. The LTFT can also adjust +25% giving a total of about 50% of possible adjustment. Using SCT software the LTFT will be opposite the STFT (LTFT of 1.25 is adding 25% fuel) while most other dataloggers will read the same way as the STFT. (don’t ask me why!). The LTFTs are stored in the ecu until it is reset by unplugging the battery, or flashing a new tune. Using the STFT and LTFT for engine component diagnosis will really help save some time. If it’s lean, look for a vacuum leak, bad injector or coil, or an exhaust leak upstream of the O2 sensor.