I'm having a little trouble dialing in my BLM's at idle. The car runs great when driving around, but as soon as I drop it into park, the BLM's just go up up up. Maybe not a big deal, but the RPM hunts a little too, like +/-50 to 75 RPM. A couple of days ago, after driving for a while I put it into park and it started surging and the SES light came on. It went off a few minutes later after driving.

I was wondering what the pros/cons are of enabling open loop idle? I see I have RPM on and off parameters I could set (currently at 25/50 RPM or something). Is that for hysteresis, like it stays open loop until it exceeds the on value, then stays closed loop until it goes below off? TIA

 

Sometimes it improves the idle and sometimes, it doesn't.
I'd suggest trying it, and see what happens....

 

I run mine open loop to 800 rpms, seems to be consistent.

 

I've been pretty happy with OLI too. Only thing is that I like to go back to CLI for tuning, to make sure my BLMs are in line. Not sure that this is the smartest way, but I don't trust my ability to tune open loop.