MarkJRust

So, it's time to get a couple opinions.

My friend and I both have XJ's with no downstream o2 sensors and no cats.

He's always ran with the fuse in (to make use of the upstream sensor?) and get a check engine light for the missing one.

I've always run (and so did my PO) with the fuse out (removing use of the upstream sensor?) and have no check engine light.
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Questions:

Does having the downstream o2 sensor missing ruin the whole system (not make use of the upstream sensor) or does it just not give the computer the information past the missing cat? (efficiency of the cat)

Does running with the fuse in (making use of the upstream o2 sensor?) give you better gas mileage and/or performance by keeping the "closed loop."
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Related Question

He popped his fuse out for the o2 sensors and made a run around the block and was getting same/similar idle and performance in his XJ, or just does it take a couple of start ups for the computer to adjust without the fuse in place?
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Anyone with first hand experience or knowledge please let us know (as I'm ready to pop in my fuse for better gas mileage)

And if running with the fuse is the better case.. are there any permanent o2 simulators so we don't get the CEL everyday? (because simulators aren't a permanent solution and need frequent adjusting).

Here we go!

odgreen

read the rules dude

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ZINGGG

odgreen

lol

odgreen

here is your best option... put a freaking cat back in it and get your mpg's back and the jeep will run better!

MarkJRust

My MPG's are surprisingly not bad compared to others (but they could always be better ) but putting a cat back on it probably would help the engine.

But, if someone can provide the answers, it will help the other members who also are in the same situation and can't or don't have to ability to put a cat back on their Jeep.

Thanks for the support guys.

MarkJRust

"cf cat converter ****"

Oh god... I just saw this. What have I got myself into now.

Guess I'll be experimenting outside of CF from now on..

MarkJRust

I just saw you bolded the whole.. don't talk about catalytic converters thing.

Guess I've been breathing too much bedliner and exhaust fumes today.

Let me copy what I wrote and you can delete this thread.