i've been combating this problem ever since i put the turbo on... i got a standalone open element iat sensor and put it in the intake tube right before the throttle body. when idling in 86* weather, the afr's will be spot on, keep on idling, let the iat temps increase to 95* and suddenly im 17-18 afr. i tried to tune the intake charge bias tables with no luck really, so now i just have the bias disabled where it only relies on intake temps. has anybody had this problem? how do i fix this?

 

or if anybody has a pretty good bias table they could send me, i dont know what else to do

 

You must be running open loop? I tried to disable that table also and trims were a lot less consistent. I run closed loop so afr's are always right on but fuel trims would move quite a bit. I've done alot of reading on this and there isn't currently an easy way to tune the bias table. The way gm has it set up seems to work the best, also there is some speculation on hp tuners forum that there is another table, not accessible, the plays into the equation. Most like to move the iat sensor out of the engine bay to combat this but I personally don't like the idea of that, I would much rather be accurately measuring the temp of the air entering the engine, I run mine in the intake right behind the throttle body.

 

yes im olsd. ill prolly just revert the table back to stock

 

i could go closed loop, but i'm not sure if kb's hot pipes have two separate o2 sensor bungs...?

 

I run the KB pipes also and the drivers side o2 is in the stock location and the passenger side is in the log right before the turbo flange. It seems to work fine BUT my gas mileage took a major hit after the turbo install and I cannot figure it out. The only things that changed were 1 point compression drop, the hotside piping, the 2 bar sd bin and 2 steps colder plugs. Before anybody flames me, I'm talking running down the highway out-of-boost mileage, went from just under 18 to 14.5mpg. I realize when I'm hot rodding it mileage will decrease. Sorry for the side track op.

 

ill do that then. i can just put back in the o2 sensors, prolly with some extensions. then run stft's in open loop right? i dont have a maf. also, my gas mileage is virtually the same, about 18-19 on the highway

 

Are you using the MAF or just SD?

LSF, I bet you have an exhaust leak.

 

just 2 bar map sensor

 

OP Sorry for the hi-jack, Atomic, whats the best way to find an exhaust leak if I do? I don't hear any leaks, I don't smell any exhaust with the windows up and the HVAC fan blowing. I'm using oem steel manifold gaskets and arp studs.