When I first start the motor, with IAT temps around 67-70 degrees (beleive the problem exists colder as well, but no data logs), while in open loop my O2 voltages are running in double digits (0.22 - 0.85v) until it reaches the closed loop temp, and then my BLMs are running right around 128 (+/- 4).

What do I need to change to eliminate this open loop idle leaness? This is a 383 with SUperRam, 28# LS1 injectors, $8D map, MAT sensor relocated to just above the filter behind pass head light.

Only changes made in tune primarily VE and spark table changes so far.

Any suggestions are greatly appreciated!

- Vern

 

Vern do you have TunerPro?
If so you need to change the Loop Open % Change AFR Vs. Temp
TunerCat is
Open Loop % Change AFR Vs. Temp

It's in the tables section.

Also you can not trust the O2 sensor when you first start the motor, my WBO2 shows 11.5 to 1 when I first start up and the stock O2 is showing .56 to .42 volts.

Also that's a long vaccum hose on the MAP sensor.

 

Is your air injection still intact? That'll inject air at the manifold before closed loop. If it's actually lean (excessively lean, that is) it will run a little rough - is it running rough?

 

Yep, it's definitely running lean, although the air injection is a good point to remember as far as the O2 sensor reading is concerned (mine is totally emissions compliant and legal).

Thanks Phil, I'll change the table a smidge and see if that helps any. May shorten my time before going into closed loop (and the temp) a little bit as well....

THANKS, GUYS!!!


- Vern