Got a code for oxygen sensor and don't know which to replace

[asghert]

87 GN. Got a code for o2 sensor. I think it said 1-1, but the mechanic unhooked it before I could be sure. It's definitely running rich. How do I know which one it is? I read there are 4 total. Is that right?

Thanks!

 

[SuperSix]

Unless this is a monster race motor - there's only 1 o2 sensor, in the passenger's side header, basically under the turbo.

 

[Boostdeznuts]

I don't think he gave an lc2 motor if he have 4 u2 sensor LOL

 

[novaderrik]

there is only one sensor- right by the turbo.. the vehicles that got 4 sensors were the 96 and newer OBD2 vehicles that are required to have a sensor after each cat to make sure they are still in place an functioning.

 

[asghert]

Never trust yahoo I guess: Where are the oxygen sensors located on a 1987 buick grand national? by the turbo? - Yahoo! Answers

 

[notacarlo]

Cold start - let idle for about 10 minutes. The CEL will come on and the engine will stumble (idle change for duration). App;y a little throttle and bring revs up to 1500 for about 20 seconds and the CEL will go away. This indicates a fouled 02 sensor. The other way is to look at your counts and mv readings via scan tool. The numbers on the narrow band (stock 02) should fluctuate between the tens and 800's - back and forth. If the number remain stuck at a number, i.e. 750mv the 02 sensor is no longer responding.

There is one 02 sensor located below the turbo where the exhaust feeds, single black wire.