Man and I thought I went to in-depth into things, you got me beat. I need to reread that last post just to make sense of things.


Anyways Ford manuals and I know for sure Bosch reccommends 100K change of all O2 sensors. Does that mean it is the right thing and what should be done? IMO, no not really. Let's look at it this way... The say 100K plug changes, I don't know about you but I haven't got or felt safe going 100K on plugs. The 60K thing on the front's sets much better in my mind, the back I'd only do once a code is set. That being said I have still failed to change mine with over 150K on all 4.

 

I have seen o2 sensors blamed alot for all sorts of problems. The early two wire (non heated) versions were notorious for getting fouled and not reacting properly. They would put out voltage and thus not set a code, but would take too long to react to mixture changes and kill fuel milage ( and emmission tests) The newer heated sensors are far more reliable. Some of the replacement intervals I have seen posted were true of the older ones, but the newer ones can go well past 100,000 and still work great. That being said, poor milage can also come from so many different causes that pointing a finger at one thing is tough. If you find a magic cure for poor milage please don't hesitate to let us know!! Thanks

 

I have not doubt that replacing them is now considered routine maint. I was asking a question pointed at the no output voltage until 600* is reached.
When I start my truck the O2 sensor is putting out some voltage.

Now the time when it goes from Lean to Rich, maybe that is the amount of time it takes to run the temp up ??

The other part that I might be missing in the PCM operation is what happens under inital startup. Maybe the low voltage is ignored until the O2 sensor heats up ( in that 10 sec area ) and it is running off the dmap on the PCM code, similar to how A/F is done with TPS > 80%. Got me, haven't gotten that far yet.

Just trying to clarify what I thought I understood, last time I thought I had the closed loop operation of the EGR system down, I had screwed up the operation vs the check process ( the over 48 mph thing under the drive cycle operation ).

Just trying to make sure if I tell someone something, that it is close to correct

Thanks

Steve