I can't seem to find the answer to this with any of the ultra gauge info, so figured I'd pose the question as a bunch of you have it. In the top right corner there is the oval. In the past, I'm pretty sure I would see that rotating around or open. Most of the time now it looks closed. Also, fuel economy has dropped this winter from my usual of 15.5 to around 13. I figured maybe it was the daily runs back and forth to the ski area, but I'm thinking maybe more. No codes showing though, and no other reasons for diminished fuel economy (newer plugs, magnacores, 93oct, etc). I have found it has something to do with the emission system but can't seem to find exactly what it is related to for the Disco. Only thing I really pay attention to is the coolant temp on the gauge but did notice that because of fuel. The heart on the gauge still "beats" but don't really understand that symbol either.
Truck doesn't seem to run any different otherwise. o2 sensors? Something else?

 

I'm not completely sure, but I "think" it is supposed to be closed. Mine is currently open, but I need to replace my O2 sensors. I believe it does have to do with the O2 sensors and should be reading as a "closed loop" system.

You may want to let some others chime in, though. I'm not 100% positive on that.

 

Yeah, the closed loop is good. Just means that the O2 sensors are reading in the normal range.

 

The user manuals are here:
UltraGauge OBDII Scan Tool User Manuals

And from it:
The Health indicator is a heart that beats roughly every second. As long as the heart continues to beat, UltraGauge is functioning normally.

The Open/Closed loop indicator provides a visual indication of the state of the vehicle’s fuel mixture control system. Closed loop is the desired and nominal condition, and indicates that the vehicle’s Engine Control Module (ECM) is using the vehicle’s Oxygen and other sensors to set the real time fuel mixture.
An open loop will normally occur when the vehicle is cold, or when the throttle is wide open, or when the engine is being used to decelerate the vehicle.
there is a problem with the overall fuel mixture system and the ECM is no longer able to determine the correct fuel mixture. In this situation the ECM uses a static table to approximate the fuel mixture. In this state the fuel mixture will likely be too rich or too lean. Continued open loop operation will likely result in a Trouble code. This indicator is not present on most Diesels.

 

Closed loop means the O2 sensors are feeding voltage back to the ECU and the ECU is making fueling adjustments according to the O2 sensors.

Think of this as a donut and it keeps looping around the circle.

Open loop is a bite out of the donut - you can't loop as the circle is broken.

The bite can be a bad O2 sensor usually which will cause open loop.

 

OK...thanks guys. Maybe my mind playing tricks on me. I know it is open sometimes, but maybe that is just on decel. Being the fuel economy has gone down, I might just be looking for anything I suppose. So, if it is open too much that would hurt MPG. Now I have to see if it is open too much.

 

Noticed this morning coasting down a long hill.. mine went into open loop. This downhill is about 1/3 mile. Temps dropped to 180 too.. lol.

 

Thanks! Now I need to go get some donuts!

 

Open loop will happen when coasting down hill as the cats cool off.
When the cats cool off, the O2 sensor can't produce voltage.
O2 sensor has to have hot exhaust gas flowing by it.
So, thinking on a long coast you may go open loop.

But ----
What if your sensor is OLD.
and it goes open look when say 600 degrees or less.
And a new one goes open loop at 400 degrees.

You may have a sensor going south or north.
Your preference.

 

Thanks jfall. I have 2 pages on the ultraguage just for o2s. I'll keep an eye.