Starts lean than rich at the strip

RickWI

New Member
Joined
Jul 22, 2001
Went to the strip this weekend for a test and tune. First time out.

Dialed in timing curve to give a very nice (traction controlled)launch of 1.6. Next I began looking at the fuel curve off the log screan and what I could not figure out is it ran lean 13.6 AF for the first 5 seconds of the run and then with the shift to third ran rich 12.5-12.6. The O2 sensor did not seem to be changing much if at all, it was in clsoed loop. The motor is naturally aspriated also. The AF program was set to 13.0 AF. I really didn't mess with this at all as I just was not sure where to go. The MAP pressures and RPM ranges overlapped very closely in the first and second half of the run as you would expect but the thing that puzzles me the most is why the O2 correction did not seem to do much. It basically stayed at +2.6 almost the whole run even though the AF was swinging from one side of set point to the other. Any thoughts?
 
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