First Time Tuner--Lean at Low MAP

[rcwilbur]

I bought HP Tuners and now have an LC1 wideband hooked up. I succesfully disabled CAGS and then ran scan data of the Wideband Air Fuel Ratio without disabling the MAF, torque management, etc. just to see the results and make sure I had everything hooked up right.

Air fuel ratios were right around 14.7 for most of the histogram (seems right because still in closed loop), however for lowest MAP it was very lean accross the RPM band. I assume that was caused by "engine braking" when I let off the throttle after running the RPM's up to 4500-5000. The AFR in these cells was as lean as 20. Does this sound right?

[Bayer-Z28]

Tune in Lambda. Much easier, IMO. And it depends what your EQ ratios are set to. Some have their cars operate at stoich once warmed up and when they hit WOT they add more fuel thru PE. Make sure the car is fully warmed up before logging and try to be easy with throttle transitions when tuning on the streets.