I've been interested in seeing how long it takes the truck to get into closed-loop both to see how horrible my short (6 mile) commute is for the engine, and also because I'm getting what I think is a lot of soot built-up in the tail pipe, which the dealer says is normal...

Now that I have a ScanGauge, the first thing I added was open/closed-loop indicator. After starting the truck yesterday, it only took about 15 seconds to go into closed loop. Thinking there was still enough heat in the exhaust, plus the heated O2 sensor, it was only mildly interesting.

I checked again this morning after sitting overnight, and it still only took about 30 seconds to get to closed loop. Outside temperature is in the low 40s, but it was in a ~65 degree garage all night.

While I really wouldn't mind if it was getting into closed loop this soon, it just doesn't seem likely.

Opinions?

 

Closed loop is a good thing. It means that it is more efficient and actually running off of the sensors. The factory tune is a little on the rich side to help prevent detonation. You are getting the soot also because your short trip doesn't allow all of the moisture to burn out of the exhaust system and the water carries and soot to the rear of the tailpipe.

 

Yeah. I know that closed-loop is a good thing. It just seems like less than 30 seconds is way too quick for the system to be able to meet whatever conditions are needed to enter it.

Good to know on the soot. I was thinking it was purely because of running too rich. I didn't know that moisture would contribute to it.