F31m

[93ty475]

As I understand this, the F31m table can help you tune your fueling for higher/lower IAT's ...My afr's are pig rich during our hot 100+ degree summer days down here and my truck is fouling plugs in those temps unless I really get on it and clear it's throat....But my IAT's aren't terribly high.....Is it that the air is just less dense on the hot days and it messes with the tune? Seems to run alot better at night when it's cooler and it doesn't seem to run nearly as rich, but still on the rich side.....I'm running 50 lb injectors now and a 50lb bin that was so graciously emailed to me to match my mods as closely as possible....Lowering the fuel pressure doesn't really lean the truck out according to the wideband...Only if I adjust it down to crazy low psi such as twenty some pounds vacuum off, will the afr's lean out some...not worth risking the motor that way imo....How can I scale this to counteract the hot outside temps I'm experiencing? I'm not asking for anyone to do this for me, just looking for direction as I would like to learn this to correct for daily weather and atmospheric changes..... below is a pic of my F31m table.....Is it supposed to say CTS where it does? Shouldn;t it say IAT? should I scale it across the board or do I have to change each and every cell....up or down?.....Also, what might you guys be using to convert celcius to fahrenheit, kelvin, kpa to psi etc...? are you just printing up a specific chart or is there a converter I can download somewhere...TIA

 

[jwaller]

Re: F31m

messing with the FP prob wont do much if your still running closed loop, things kinds work funny that way.
and ya most of the lables for those charts dont actually match what they really do.
good luck, not too many ppl have gotten it to do much.
and yes the air really is that much less dense at high temps.

 

[93ty475]

Re: F31m

yea, I was hoping to mess with f31m today, but it's not going to happen....tomorrow's another day...I plan to run open loop full time, but I'd like to get it "close" in closed loop before I go open....Thanks john....I'm all ears if anyone has anything they'd like to add....

 

[jwaller]

Re: F31m

running open all the time is much better way for me to tune, it stops the ecm from masking whats actually going on.

 

[leroy]

Re: F31m

Hola Servando,

I'd make some changes in the F29 table first, since you are rich even when it's cooler.

I also agree with John about running open loop. IMO, the only good reason to run closed loop is to keep your catalytic converter healthy.

I use this link for conversions:
http://www.speckdesign.com/Ttemperature.cfm

I believe the f31m scale is in degrees celsius. The values are multipliers for the fuel calculation. Notice it's an inverse term. I don't think you should have to mess with these much. Your table already looks like it is quite a bit different from stock....maybe return it to stock values first. Most engine modifications shouldn't affect the temperature term, IMO.

HTH,
Jim

 

[93ty475]

Re: F31m

thanks Jim....I'll try what you said....I can also return f31m to stock values to see what it does....