cliffyk

First some background:

The perfect (called stoichiometric) air/fuel ratio (AFR) for gasoline is 14:7:1; 14.7 parts air to 1 part fuel. When burned in this ratio all of the gasoline is consumed, this is where maximum fuel efficiency is achieved.

• Rich is when there is less than 14.7 parts air, I.e. when the "air" number is less than 14.7;
  
• Lean is when there there are more than 14.7 parts air, when the "air" number is more than 14.7;

Maximum power happens with richer AFRs; 12.5 to 13.0:1 running n/a, and 11.5 to 12.0:1 running f/i.

The stock O2 sensors are what are known as narrowband O2 sensors, called such because they can only accurately indicate AFR withing a narrowband of 14.6 to 14.8:1. outside of that range they can only report that the mix is rich or lean.

In closed-loop mode the PCM uses feedback from the front narrowband O2 sensors to maintain and average AFR of 14.7:1. It does this by continuously reading the sensors to determine if the mix is rich or lean (as described above) and then varying the injector pulse width to maintain and average AFR of 14.7:1. This constant variation of the AFR is why when in closed loop mode the AFR reported by a wideband system will slowly oscillate from rich to lean around 14.7:1.

Closed-loop mode is used when the engine is idling or at loads of less than 65% or so.

When the load (as determined by rpm, airflow, throttle position, and a few other PCM inputs) goes over 70% the PCM enters open-loop mode in which the signal from the front O2 sensors is ignored and fueling is controlled by look-up tables and modifying functions (based on IAT, ECT and other factors) in the tune.

So: 14.7:1 is the target for closed-loop mode, but the WB reading will vary on either side of 14.7:1 constantly--as much as 14.0:1 to 16.0:1. In open-loop mode, depending on how much boost (if any) the target AFR will be richer 12.5 to 11.5:1, maybe 11.0:1.

You 10:1 at idle is too rich, but as I said there is little to no point worrying about that at this point.

Have you discussed this with your tuner?

disposablehero27

I haven't in which i had just got the car driveable. As I started it on 4 jackstands, I just noticed the array of white smoke and fuems filling the garage pretty quickly. Doesn't smell like oil or gas, but its hard to say. So i took the video and recorded that white smoke. I pulled it out just in the driveway, verified it would move to make sure clutch cable was correct. I took it down a 1/4mi decline, pulled back up and noticed the numbers. 10.0 dead stop. up to 16 which is max all the way to the right and red, when i pressed the gas at any time, even very gently. So when i got back, i parked and got on here just to be safe. Does my fuel psi from the regulator directly relate to my a/f mixture?