Cmeix

Hey, i was just wondering if anyone could maybe help me with my situation....

I just recently got my EVO 9 dyno tuned and everything. I live in Canada, so it gets pretty cold here and i daily drive the EVO as well.

What i have been noticing with my Air and Fuel ratios that when it gets real cold like in the negatives in Celsius, my air and fuel ratios begin to

RICHEN UP, not lean out but when it gets warmer my ratios LEAN out but not richen up...


So i was just wondering if anyone could kind of let me know what may be wrong with my car? Because i thought that when there is colder weather, your ratios should lean more than rich and when the weather warms up more it richens than lean....

HELP PLEASE !!

4b11slayer

Its probably going into open loop. And open loop usually is rich.

RightSaid fred

What mods to it?
If it's stock, there's nothing to dyno tune........all you're going to do is screw everything up.

Cmeix

Does that mean my car can also go into open loop when it's idling rich as well? I see my ratios go down to like high 12s on Idle on cold days... and even when I'm cruising, everything gets richer.

Cmeix

My motor is fully built, top and bottom end.
1000cc inj
gt30 turbo
all your bolt ons
etc, etc.

I don't see why i tune would screw anything up.

4b11slayer

If its so cold that the coolant temp drops im sure thats what it is.

Cmeix

Would there be a way to properly fix this???

ronaldo9

iTrader: (2)

That is typically the behavior until the car has warmed up. If the car was tuned have the tuner look at the tables but this isn't necessarily a bad thing. What are the ratios exactly? What are your fuel trims like? Also are you running a regular thermostat or something like a mishimoto 63 degree thermostat?

Cmeix

I am running a normal thermostat with an upgraded mishimoto rad.

The behavior that i am talking about is AFTER everything is warmed up, and driven a little to basically get the car into warmed up temps.

My tuner touched upon the INJECTOR scaling, but it fixes the cold weather days but once it starts to get warmer, the car runs leaner than it should... So i find it weird.

My ratios at idle go down to like 12s on cold days, and also WOT is basically 10s... cruising speeds are in the 13s..

These are all on cold days, without tweaking anything on the tune..

ronaldo9

iTrader: (2)

Are you on speed density or maf?

Cmeix

I am on speed density.

4b11slayer

Adjusting high octane fuel map. Since open loop relies on the fuel maps to run. What coolant temps

RightSaid fred

That explains everything.

You've probably got the IAT sensor in the usual wrong place.




Go back to MAF and you won''t have problems.

ronaldo9

iTrader: (2)

There's a thread on here where people on speed density are having similar issues and adjusting certain temp scaling tables helped.
https://www.evolutionm.net/forums/ec...y-problem.html

gixxer1621

also check coolant temperature sensor