Quote:
Originally Posted by thambu19
@ arghx7 @ solidONE @ steve99 @ Kodename47 @ ztan
My concern is if the fuel trims go up or down too much say more than 10% it will take the estimated load along with it. Estimated load = Originally assumed load through MAF signal +- corrections from fuel trim. This means the cam and spark lookup will move around unnecessarily?
I dont know how exactly it works on the FA20 so this is just my assumption. This is assuming that most OEMs trust their fuel modeling more than air flow modeling. So when fuel trim moves the load estimation moves as well.
My other concern is how is MAF scaling going to fix this? For example say if by going 100%PFI at low loads causes the LFTF there to go 10% +ve causing a load estimation to go up 10%. The MAF there would be moved up 10% at the same Voltage to bring the LTFT to 0% but we still have the same problem because now the MAF readings are higher (artificially) causing a higher load estimation and hence spark/cam lookup = bad combustion or knock depending on which direction we go in load lookup |
Fuel trims, on my car, has not increased beyond 9% (idle LTFT) after changing the port injection ratios. I'd say at most +4%~6% LTFT in the "problem" areas aside from idle speeds. My main concern it the fluctuations in fuel trims seems to be bumping up the LTFT in OL operation causing it to run a bit richer than before. I wouldn't call it a 'huge' concern, but it is something I think I'd address. If anything, I just want to mess with it and see how close I can get it to requested AFRs as I can.