How can I tell if my Oxygen Sensors have gone bad?

FastGT94

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Jul 12, 2004

#1

• Jul 12, 2004

• #1

If the sensors go bad, will they throw a code in the Engine Running mode? If not, how can I tell if they're bad or not? What are some symptoms? I'm chasing down a lean condition and want to know if they could be my problem.

Thanks!

 

FastGT94

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#2

• Jul 12, 2004

• #2

ttt Help??

 

HISSIN50

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#3

• Jul 13, 2004

• #3

wont necessarily toss a code. they should range from 0.1 to 1.0 volts. as they age, they dont read right (so fuel is not trimmed as well as it could be) and they get hysteretic.

you can grab a DMM and check them. higher volts is richer. until they totally crap out, the CEL may not come on.
more info on your lean condition??
good luck.

 

HISSIN50

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#4

• Jul 13, 2004

• #4

ah, just saw your other thread with the codes. if both O2's are old, it can be them, or more likely is a primary fuel issue (pressure, FPR, vac leak, etc).

see other thread for a little info on testing O2's.

good luck.

 

mo_dingo

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Jul 13, 2004

#5

• Jul 13, 2004

• #5

What is this lean condition you speak of? If the car is lean at wide open throttle or when the motor is cold, then your O2's are not the problem.
Scott

 

Rootus

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Jul 13, 2004

#6

• Jul 13, 2004

• #6

mo_dingo said:

What is this lean condition you speak of? If the car is lean at wide open throttle or when the motor is cold, then your O2's are not the problem.
Scott

Click to expand...

Not necessarily. Open loop tuning is based on closed loop tuning.

 

Venom351R

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#7

• Jul 13, 2004

• #7

usually they need to be replaced every 50,000 miles or so. Sometimes you can tell if it smells like unburnt fuel comming out of the exhuast, more rich then it usually is.

 

FastGT94

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#8

• Jul 13, 2004

• #8

My lean problem is at all ranges, it even smells lean at idle. We added 10 lbs of fuel (52 psi with 24# injectors) and the A/F didn't change at all throughout the range (16/1). Some people are saying vacuum leak but I haven't found one yet. I'm in the process of tearing things down, sending the injectors out to be flowed and cleaned, looking into getting a new AFPR and re-doing the intake gaskets.

So from what I'm understanding, even if my O2's were absolute crap, the car would be rich and not lean, correct?

HISSIN50, I didn't see any other posts by you in the thread with the codes.

All help is very much appreciated!!

Thanks!