Open loop and closed loop

[Snake31]

My 2011 M56x seems to drive differently every time I drive it. I've taken it to two different dealers and both have said there is nothing wrong with my car. Today I put a ScanGauge II on it and noticed that it stayed in closed loop on the way to work this morning until the coolant temp got up to about 180F. At lunch it seemed to bounce back and forth between open and closed loop even well after warmed up. It seemed to stay on closed loop more. Any thoughts?

[Ilya]

It should change within 30 seconds of starting the car...we thought this is why the V8 guys have that 'hum' when the car first starts...

[Snake31]

My thinking was backwards; I though that cars started up in closed loop to run on preprogrammed info and then switched to open loop to adjust for info from sensors. I guess it starts in open loop then changes over to closed loop upon warm up. That being said, once my car warms up it is in closed loop when pushing the throttle but will go into open loop once I start coasting. Is this normal?

[mikedamageinc]

Yes I've seen that in other cars too. I have an ultra gauge in my Camaro and occasionally put it in the Land Cruiser and it does exactly that. Now if it starts going into open loop while normal driving, it could be an O2 sensor problem. But going open during braking or coasting to a stop is normal.

[armybrat]

My thinking was backwards; I though that cars started up in closed loop to run on preprogrammed info and then switched to open loop to adjust for info from sensors. I guess it starts in open loop then changes over to closed loop upon warm up. That being said, once my car warms up it is in closed loop when pushing the throttle but will go into open loop once I start coasting. Is this normal?

Actually yes, it is normal to switch back and forth, to maintain proper A/F ratios for your driving situation at the moment. Normal driving it will pretty much stay in closed loop. You can change the closed loop parameters with a custom tune so your car will run leaner. These cars run rich from the factory.