Here is a great example of why using DynAir is so great. This is my latest log and my fuel trims are skewed a little since I have been playing with EOIT, but that gives a good opportunity to inspect this.
We are zoomed to 30sec and we can see throttle is slightly increasing, but overall pretty smooth and steady input.
MAF and DynAir agree with each other
124 g/s (so the ECM says we are in steady state)
Fuel trims are both negative at a
-5% average between the two banks (LTFT is disabled btw). This tells us that
124 g/s is too much air...
And we can see VVE is reporting in at
113 g/s
So if
MAF & DynAir are rich we need to reduce MAF by the fuel trims:
124.558 g/s * .95 =
118.33 g/s
And since VVE is still less than this newly identified corrected airflow, the
DynAir VVE_CL formula at the top says you need to ADD air to VVE!
113.625 g/s * 1.0547 =
119.84 g/s
We can now see that both MAF and VVE are converging around
119 g/s. Pretty good agreement, which is what we want.
YET...WHAT DOES
GMVE TELL US TO?! It says VVE is rich and to REMOVE air to the tune of
3.76%! Why would I want to remove air when the fuel trims are rich for MAF and VVE g/s is lower than MAF?
113.625 g/s * .9624 =
109.35 g/s
This will make fueling worse by 9% (from 119.84 g/s target)
Here is the GMVE formula I am using. If there is an error then please enlighten me:
Code:
([50040.71]*(1+((.01*[50116]*100)+(.01*[50114]*100)))-(([50030.92]*[2312]/[2126.240])*[50070.56]/60*4))/(([50030.92]*[2312]/[2126.240])*[50070.56]/60*4))*100
chartVtime.jpg