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Old 09-12-2013, 12:43 PM   #31
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Quote:
Originally Posted by Reznor View Post
Here's the thing about the O2 sensors, and why I ruled them out in my own situation:

Firstly, there is no CEL. This doesn't necessarily mean they are not at least somewhat faulty, but is a good start.

But when a vehicle is first started, it runs in open loop - completely bypassing the O2 sensors until it warms up and then goes into closed loop. So if the idle/running occurs when the vehicle is dead cold, then it shouldn't be the O2 sensors.
I didn't know about the open/closed loop. Does that apply to all vehicles or just jeeps?

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Old 09-12-2013, 10:38 PM   #32
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All vehicles, though there is some learning done that the ecm applies to the next start.

My jeep ran the same way before and after all 4 new o2 sensors. NTK brand. One cleaning was before changing the sensors and one was after. As said, it runs smooth and quiet after cleaning for about a month.. a little less actually the 2nd time. Runs fine on the road and no check engine light. What I really found interesting was the effect of the pure fuel vs E10.

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Old 09-14-2013, 10:44 AM   #33
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Originally Posted by Jerry Bransford View Post
I'd bet more on one or both of your upstream 02 sensors being bad, I really doubt your fuel injectors have anything to do with your rough idle.
Thats where I first started. I had a cel light come on showing the bank 2 sensor 1 was bad, so I changed it out but i figured since they were pretty cheap I would replace all of them. since I did that I have had no cel light come on.
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Old 09-17-2013, 01:34 AM   #34
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Bump

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