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Dying O2

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Rahdigga8188

15+ Year Contributor
97
1
May 18, 2006
Savannah, Georgia
Well from all the things I've read i think my O2 sensor is taking a dump on me. I have horrible gas mileage, it doesnt cycle at idle, I blow huge clouds upon acceleration. But the thing is when i watch my logger I looked at the fuel trims and I'm at 118%, 100%, and 96% for my low medium and high settings. Isnt that adding alot of fuel in the low area. Also my O2R readings never go above .80 at wide open throttle, and from what I've read that seams lean. I'm confused. I would test it but what harm can getting a new one really do?
 
Rahdigga8188 said:
Well from all the things I've read i think my O2 sensor is taking a dump on me. I have horrible gas mileage, it doesnt cycle at idle, I blow huge clouds upon acceleration. But the thing is when i watch my logger I looked at the fuel trims and I'm at 118%, 100%, and 96% for my low medium and high settings. Isnt that adding alot of fuel in the low area. Also my O2R readings never go above .80 at wide open throttle, and from what I've read that seams lean. I'm confused. I would test it but what harm can getting a new one really do?


A dying O2 sensor will typically read lean - instead of cycling smoothly through the range of 0 - 1.0 v it'll just hang out at the bottom end, barely cycling, if at all. Yes, 0.8v is lean at WOT & that 118% FTRL means the ECU is trying to add a crapload of fuel because your O2 sensor is telling it (incorrectly) that you are lean. The ECU adds a bunch of fuel you don't really need & you get crappy gas mileage. So yes, get a new 1, preferably from a dealer or www.sparkplugs.com (I think that's the place). Don't get a universal type sensor - you'll have to splice into the harness & that's no fun.
 
i think extremepsi sells the factory ones in their site for about 70-80 bucks or less. Pretty cheap after a weekend on c16.
 
SexperT said:
i think extremepsi sells the factory ones in their site for about 70-80 bucks or less. Pretty cheap after a weekend on c16.

Better yet, the OEM-identical Denso sensors at sparkplugs.com are roughly $53 ea. & race gas friendly -

"Constructed with Denso's exclusive aluminum oxide trap, this extra layer helps to protect from silicone and lead poisoning which causes premature sensor failure." :rocks:
 
Gromit said:
A dying O2 sensor will typically read lean - instead of cycling smoothly through the range of 0 - 1.0 v it'll just hang out at the bottom end, barely cycling, if at all. Yes, 0.8v is lean at WOT & that 118% FTRL means the ECU is trying to add a crapload of fuel because your O2 sensor is telling it (incorrectly) that you are lean. The ECU adds a bunch of fuel you don't really need & you get crappy gas mileage. So yes, get a new 1, preferably from a dealer or www.sparkplugs.com (I think that's the place). Don't get a universal type sensor - you'll have to splice into the harness & that's no fun.

Bingo. Great post Neal.
 
Ok thanks for clearing it up. I figured it was dying, just needed a second opinion :thumb: So My car should run better once i install the new one? Because it feels good now, so better would be great:D
 
I'm having the same problem, I think my o2 sensor is going also, I don't have a logger or A/F gauge. I'm working on that though, I get horrible gas mileage and it also puffs, I'm trying to narrow it down, should I just replace the stock o2 sensor or should I get an aftermarket one, whats a good brand if aftermarket also?

Thanks, Mike
 
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