what EXACTLY is Gammae?

uberbug · Post by **uberbug** » Sun Feb 12, 2006 11:42 am

I have read the manual and I'm still confused about what is Gammae.

Corrections to mixture I can see are:
Gego - correction per the o2 sensor
Gair - correction for air density (based on air temp)?
Gwarm - correction for warm-up?
Gbaro - barometric correction
TPSacc - TPS based accellerator enrichment

is Gammae a combo of ALL these enrichments?

if I have Gammae OFF which enrichment factors are ignored?

The reason I am asking is: I've noticed lately that my mixtures are off by like 10% according to my WB O2 sensor. Ironically my Gammae on my logs is around 90%

uberbug · Post by **uberbug** » Mon Feb 13, 2006 11:13 pm

BUMP

I am still trying to figure out which enrichments contribute to the overall Gammae...

mops · Post by **mops** » Tue Feb 14, 2006 11:35 am

well... i dunno either and I'm keen to find out...

Jedrik · Post by **Jedrik** » Tue Feb 14, 2006 3:00 pm

When I have a question like this the first place I go is strait to the code.
With MSII for example the fuel equation is:

Code: Select all

/**************************************************************************
**
** Computation of Fuel Parameters
** Note that GAMMAE only includes Warm, Tpsfuelcut, Barocor, and Aircor 
** (EGO no longer included)
**
**************************************************************************/
  	lsum = ((outpc.warmcor * outpc.tpsfuelcut) / 100);
  	lsum = (lsum * ((outpc.barocor * outpc.aircor) / 100)/100);
  	outpc.gammae = (int)lsum;
  	if(inpram.FuelAlpha != 2)
  	  lsum2 = (long)outpc.kpa;
  	else
  	  lsum2 = 1000;	         // normalizes to ~1 when divide by baro 
  	lsum1 = (lsum * ((outpc.egocor1 * lsum2) / outpc.baro)/100);
  	lsum1 = (lsum1 * ((outpc.vecurr1 * (long)inpram.ReqFuel)/ 100)/ 100); // usec
  	lsum2 = (lsum * ((outpc.egocor2 * lsum2) / outpc.baro)/100);
  	lsum2 = (lsum2 * ((outpc.vecurr2 * (long)inpram.ReqFuel)/ 100)/ 100); // usec

From this I see gammae is set after warmcor, tpsfuelcut, barocor and aircor are combined.

Then you do some searches with your text editor to see how the corrections are calculated. I notice for example that tpsfuelcut is only <= 100% and only active during decel never actually an AE. (The AE is added in later in the code.)

uberbug · Post by **uberbug** » Tue Feb 14, 2006 5:37 pm

Thanks!

I'll have to get a copy of the code and check through there too I guess.

Looks to me like it doesn't include o2 correction (Gego) and Accelleration (TPSacc?) which is what I wanted to know.

jsmcortina · Post by **jsmcortina** » Wed Feb 15, 2006 5:43 am

Don't turn GammaE off unless you are using dual tables and a non-fuel such as water on the second channel.

If your GammaE is 90% not 100% you need to fix the variables leading to it like warmup etc.

James

uberbug · Post by **uberbug** » Wed Feb 15, 2006 9:01 am

I think I figured out that it is 90% because my IAT is reading 125f. I'm not sure why the intake air would be that hot so it might be a bad reading or it could be that I am getting too much hot air in my engine compartment (it was a 55f day out when I did the test).

The warmup settings minimum is 100% so it is not causing it.