How many o2 Sensors????

[The Dalek]

Hey!
I just bought a 1996 Marquis LS w/ 80K miles and its tossing o2 codes. I have one new cat converter and the codes keep popping up so Im guessing the sensors are bad.

My question is how many exhaust/o2 sensors do I have and are the upstream and downstream the same part?

[gadget73]

4. the rear ones will give you catalyst efficiency codes, the front will give you lean or rich codes. Don't assume its the sensors though, they may be telling you there is actually a problem somewhere.

[The Dalek]

Awww man.
What type of problems?

[gadget73]

vacuum leaks, dirty MAF, leaky injectors, dead plugs, dead wires. What codes exactly are you getting?

[The Dalek]

lets see....
p1151
p1132
p0135
p0133

[86VickyLX]

Not the catalyst code. Slow responding sensors and heater circuit failures. Also one for a sensor not switching always lean. This could indicate some vacuum leaks as Gadget said. But the sensor itself could be bad too. But here's some questions to narrow down the diagnosis. Are the sensors hooked up and are the wiring harnesses in good condition mang? Are the connectors clean and free of dirt, oil, rust etc?

[The Dalek]

Not the catalyst code. Slow responding sensors and heater circuit failures. Also one for a sensor not switching always lean. This could indicate some vacuum leaks as Gadget said. But the sensor itself could be bad too. But here's some questions to narrow down the diagnosis. Are the sensors hooked up and are the wiring harnesses in good condition mang? Are the connectors clean and free of dirt, oil, rust etc?

Ahhhhh I dont know if they are hooked up. I dont know where they are. My skills as a GM father seem to be rather poor.
So none of those are o2 sensors?
Is it about the MAF sensor?
Ohhhh MAN! I hope this is easy to fix. Ive given her a new Cat coverter, 2 new brake lines both to the rear brakes, a new battery and a chrome tipped exhaust (for looks of course)

Is there a way I can find where all these damn sensors are?

(thank you BTW)

[gadget73]

Those codes say the O2 sensors are reading fuel mix problems. Either there is a fuel mix problem and the sensors are telling you the truth, or you have dud sensors. It could be either, but I never replace sensors without checking other stuff because I'm cheap. More often than not, the sensors are telling you the truth and you have to figure out why. Sensors in general are very reliable devices, and computer diagnostics are useful but they can only point you in the right direction, they seldom will tell you with absolute certainty "this is the problem, replace that part".


Shop manuals will have locations of all the parts. Your car should have one available on CD for not a fortune.