Spark Plugs with Two-Step

[Ed Wright]

Bobby, mine doesn't automatically go into Open Loop on the 2 step. Are using the FAST 2 step?
WOT is the only place I use Closed Loop. Unless you have really long collectors, or the O2 sensor before the collector, at idle & low RPM driving around the pits, cams with a lot of overlap like we use, it will pull clean air back in the collector during the overlap cycle. That looks lean to the ECU, and it will add fuel. I had a muffler shop make me a long slip-on extension with a 30 deg bend, for tuning my idle and part throttle. That stopped it from pulling in clean air during overlap, and made the sensor read correctly. I put in closed Loop for that, and just kept tapping the L key while I drove up & down the return road with that extension on it. Then back to open Loop there.

I use closed Loop going down the track. It never makes corrections anymore. My VE table is pretty well dialed in for any weather & elevation I run at any more.