Closed loop only has two modes of operation. Idle mode and cruise mode. Both needs to be at operating temperature. All other modes are open loop. Something to consider seeing the EVAP at cold start up runs diagnostics.

 

Erm, I don't think thats quite accurate. Closed loop simply means the PCM is using the O2 sensor to monitor fuel trim. Our trucks go into that mode quite rapidly, thanks to the heated O2 sensors. I wouldn't be surprised to learn that there is some temp constraint to it as well, but, if it is much over 100 degrees, I WOULD be surprised.

 

http://www.pacificautotronics.com/MO..._Operation.pdf

Ermm, it is quite accurate.

 

I don't see where they define "warmed up". Nor do I see where they define "normal operating temperature". If the programming is that literalist, NO ONE with a 180 degree thermostat would ever go into closed loop mode.

Operating temp is usually defined as a Range, not a hard number. For GM products, they will drop into closed loop at 106 degrees F.

Granted, there is FAR more information available for the GM systems......

 

Why is everyone so argumenative about which they dont understand on this site is beyound me?

 

Back up your argument with facts.

 

I believe I had read in the FSM that closed loop happens at 147*. My Snap on scanner just counts down from 2:00 minutes and then proclaims closed loop.

 

I think when the opportunity presents itself, I am going to see if I can borrow the shop scanner, and test some of these things. That, and I am getting crappy gas mileage..... single digits...... and I have too many new engine parts to justify that.

 

2 min would be "about" right for when the issue occurred after starting the truck for me, funny thing is now since I changed the ABS sensor the issue is gone along with the p0305 code....not sure how any of this is connected but the last two days it has not done it.

 

It's because you're highly skilled at making friends and influencing people, not to mention extraordinarily knowledgeable, and we all just want an excuse to converse with you and remove all doubt of our vast inferiority. Speaking strictly for myself, that is... I refer to my idealized self and my crippling inferiority complex as "we" because they don't get along very well and there's no telling which one's at the keyboard at any given time.