It takes my car a very long time to go to closed loop, even when the engine is opperating temp. If it has idled for a min, it may take the thing a minute or more of being revved up to around 1700 or higher to go back into closed loop. Is this the O2 going away??? It is kinda annoying to scan, esp around idle to clean it up, if you cant let it idle more than 10 sec and then gotta rev it up to go back in. TIA
Bob

 

Actually, if you just let your car idle, it will never (or rarely) go into closed loop. In fact, if you were driving (and in closed loop) and then got stopped in traffic for a prolonged period of time. After 5-10 minutes, you will go back to open loop. That is a major reason a lot of cars fail emission testing.

There are "timers" that you can set the minimum time to go into closed loop for "cold, warm and hot" starting.

 

Glenn
I did set the timers lower. The problem is, after it goes open loop, it may take 5 min or more of higher rpm to go back into closed loop. I figured at 2000 rpm, it should go closed pretty fast, but it wont.

 

If you too far off on your calibration, the O2 will never develope the necessary swing in voltages to go closed loop.

May also need to go to heated sensor.

 

What are your O2 volts doing?

BTW Glenn, AirCare around here does the 50km/h test first, then idle. I think that's so cars go into closed loop. I'm not sure what happens when we move to the IM240 testing.

 

My O2 volts drop like a stone when it goes open loop. Was at 675 mv, 1100 rpm(closed loop), started dropping, within .3 sec its at 275 mv 1100 rpm (open loop) and still falling. even tho i kept it revved up, it still went open, and had low mv. Grumpy, how do you wire in a heated O2? I may have access to a very high end sensor for "loan", but its either a 3 or 4 wire. Do i just plug in the sender wire, and run the others to ground and 12v keyed or ??? Obviously my car only has a 1 wire connector for o2, so I have been kinda wondering. Thanks for your time. Also, if I am going to autozone to get 1, what vehicle would I get 1 for? ( Best fitting, best working etc.)
Bob

 

Alex, AirCare has changed their procedures from when they FIRST started doing testings. Originally they ALWAYS tested idle first at the stations I went to (Willingdon in 1991 then Abbotsford from 1993 to 1999).

PS: You are already IM240. That means "dyno" testing with simulated speed. AirCare just doesn't enforce CARB or EO numbers. Just "blow" you number and you make it.

BTW, the number I ORIGINALLY had to blow in 1991 was identical to Californias. Now, it is about 1/3 of the original number for 1991 GTA. There is a LONG political story of why this happened, but it just pisses me off everytime I think about it.