Attention Bill, and Tuners of Australia
We are currently in the process of developing & testing a factory standard 2008 FG falcon xr6 turbo 6 speed automatic with only 60ib Injectors, Racecraft cooling system Mod & the aid of hp tuners/Vcm suite.
All our WOT tuning EG,Boost curve,IG curve,Afr with the 60ib injectors has been completed on a chassis dyno.
Im having a problem at anywhere between 80 to 100kph, 18 to 21 % throttle @ cruise or with cruise control on, the Air fuel ratio fluctuates between 14.5 to 13.6.Prior to fitting 60ib injectors AFR fluctuation still occurred @ cruise.
I have logged data via a fuel base vs rpm vs tps pid on the scanner and highlighted the cells were fluctuation occurs and noticed a 14.5 afr reading although it doesn't read the 13.6 afr drop in the scanner cells.
I inspected the fuel base table in the editor and the Lambda reading is 1.0 four cells across and 4 cells down which is standard lambda readings.
I've also checked the cold fuel base tables in relation to our cruising cooling system temps Lambda is 1.0 four cells up and four cells across.
I've tried to remove several provisions in relation to cruise although I have been unsuccessful.
Just came back from a road test and thought id update towards what I have found.
Ive nailed it down to being the STFT to be correcting the AFR for some reason @ cruise. I've tried to remove closed loop correction by increasing the closed loop 02 sensor Temperatures so that closed loop would not come on.
Also increased the numbers closed loop delay vs start up ECT and switched off LTFT learning switch.
With the cruise control set @ 80 and 100kph the AFR is perfect and holds a constant 14.6 AFR no fluctuation. 4.5minutes driving the vehicle the STFT start to correct the AFR, Then a wave form of fluctuations from 14.6 to 13.9 AFR Occurs.
If anybody could shed some light on the surging problem i'm having that would be great.
Regards