mike89z

Just wondering what is used to determine proper idle when car is in open loop. Im curious because a lot of people seem to have idle issues (big surges)after a cam swap and I was curious why that was. I personally just discovered that my fuel pressure is up a little at idle(only 12" vacuum at 750) and seems like the IAC is trying to compensate which raises the idle which brings down the pressure. Seems like a viscious cycle but only happens when it is in open loop. In closed it does not have the surge. Maybe once the O2 can compensate it fixes it? Just felt like gettin a discussion goin becuz it seems to be a pretty common issue. Not really sure if this is the same with the MAP system, if so chime in. By the way, right now I just opened up the throttle blades so the IAC isnt needed and seems to be a lot better (just a small surge and not even close to stalling when put in gear).

Grumpy

The only difference from open loop to closed loop is correcting the AFR based on feedback from the O2.

Disabling Closed loop, and using a WB makes recalibrating the MAF tables and scalars rather easy.

Shy if that letting the ecm going closed loop and then tune to get the BLs half close to 128s can sort of work.

Depending on engine combo., you might want to add a little timing in addition to some fuel at idle. Some engines like as much as 26d timing at idle.