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Extinct
March 29th, 2009, 04:27 PM
Guys, wondering if anyone has every observed this.

Mostly stock LS1, tuned VE anyway (although stock table very close, within .03 everywhere).

Run up through the gears, looking at the log, the Dynair steadily increases as you would expect, commanded AFR is rock steady, but WB reading bounces around as much as .5 in a bit of a sine wave fashion from one frame to the next.

I did not log injector duty cycle or pulse width, but given that the dyncylair is very steady and commanded air flow is very steady, I would have to assume the injectors woudl be commanded at a steadily increasing cycle.

Possible causes ?

Bad plugs (allowing comb to be incomplete?)
Injector cycle variations (I will log next time, but perhaps difference between commanded and actual - bounce?)?
Reversions ? Airflow variations ? (although one would assume as engine rpm is increasing steadily and TPS is 100% that there would be very little variation).

Thoughts ?

5.7ute
March 29th, 2009, 05:48 PM
In closed loop the AFR will fluctuate as the O2 sensors switch. Are you sure this isnt what you are seeing?

Extinct
March 30th, 2009, 12:01 AM
No, not closed loop, WOT with AFR around 12.5. I will post a log chart later today for reference.