I'm fairly new to tuning, just reading lots to try and learn some of the basics.
It seems like most fuel tables are not visible for the LNF in HPT, is that correct? Other than a few settings like Fuel Pressure Limits, etc., it seems the only map is Power Enrichment Lambda, correct? Can I tune just changing that table as far as fuel (I realize there are lots of other non-fuel tables, but I'm just talking fuel)?
(I have a Solstice GXP)
Attachment 127910
I'll be interested if the more experienced LNF tuners way in, but I would say yes. You will have to be careful since it easy to call for boost/need more fuel without the expected Driver Demand Torque, depending on how you adjust the other tables.
Be ready for having a lot of "indirect" changes since you can only see a few of the tables that control.
the lnf is a closed loop ecm for wot meaning uses fuel trims so the answer is yes and not exactly to your question. yes you can adjust the lambda command/actual to what you'd like and it will command/actual to be just that but you also need to adjust the maf data to get fuel trims within 5% error to insure you're getting enough fuel. example. you can make the lambda be a .85 across the board lets say but your fuel trims during wot might be -20% or more so youll need to remove the fuel to bring the trims into spec
Thanks all for the info.
The LNF ecu does not operate in Enhanced Speed Densitiy like the LSJ or Gen3/4 LS ecu's. The MAF is required to maintain high accuracy and there is plenty of range when installed correctly into aftermarket setups. There is a way to fake the ecu out and run without the MAF but we don't recommend it because it impacts the calculations and you end up crutching certain things to make it run right.
As mentioned by TCSS07 the LNF comes factory with a wideband sensor installed in the B1 position and it actively adjusts Enrichment Fueling usign STFT and LTFT feedback loops. This means you don't need to purchase an external wideband to tune these engines, and can easily tune the entire MAF maps in a few passes using simple STFT+LTFT Histograms.
Fuel Tables consist of:
1) MAF Calibration: Airflow vs. Frequency (its an airflow table but directly effects fueling)
2) MAF Correction: Base (airflow table like above but directly effects fueling)
3) Flow Rate: Injector Constant (Used to adjust major injector offsets typically caused by swapping to Ethanol blends)
4) Power Enrich: Lambda (for setting target lambda in enrichment mode, not for adjusting fuel to fix WOT error)
5) Component Protection - Target lambda: Lambda B1 (for setting target CAT Overtemp Protection Fueling, do not recommend changing if you have cats installed)
6) Desired Fuel Pressure: Normal (Target Rail Pressure for Normal Injection Mode)
7) Normal Mode: Pressure A (Rail Target Pressures for Hom Split Injection Mode)
Great info @cobaltssoverbooster ....thanks much! That helps clarify.
i went back to your older post about the 42lb/h gm injectors in a 2.2 cobalt with your tune chart. is this chart made for a base engine with the added injectors or what does it do? im at a stump right now because i just installed them on my car, i haven't done the tune yet but the injector offset vs volts vs map chart wont let me input the same specific values as yours. are you able to help me out because i dont want my car running extremely rich since it is not tuned for the new injectors.