o2 sensor

[jakez28]

I found out i have a bad o2 sensor causing me to run lean. when i replace it what exactly should i replace, the whole wiring harness or just the sensor? i know its located right next to the cat going into the manifold but is there just one sensor id have to replace or is there another one also?

[c5z28]

Should just replace the sensor

[jakez28]

someone told me that ls1s have 4 o2 sensors, and id have to run an OBDII scan to see which ones need replacing is that true

[c5z28]

someone told me that ls1s have 4 o2 sensors, and id have to run an OBDII scan to see which ones need replacing is that true

Yes 2 before the cats and 2 after, if you don't know which one get it scanned-no big deal.

[khickenwang]

Does bad o2 sensors make you use more gas than normal? Because 2 of mine went out and I burn a whole tank of gas in 1 week and I do little driving to work. I have long tube slp headers and borla exhaust stage 3 clutch

[c5z28]

o2's tell the computer if you run lean or rich so get that fixed.

[khickenwang]

o2's tell the computer if you run lean or rich so get that fixed.

I got them fixed today but what does that mean? run lean or rich?

[c5z28]

I got them fixed today but what does that mean? run lean or rich?

Usually rich, but the o2 reads if the motor runs lean or rich and adjusts accordingly. If you don't have o2's then the car has no way of teling

[pajeff02]

Run rich = to much fuel

Run lean = not enough fuel

The optimum air fuel ratio is appoximately 14.7 to 1. This is called "stoichiometric". For every 14.7 parts of air, the combustion chamber wants 1 part of fuel. In a nutshell: Running an engine lean increases combustion chamber temps and can result in knock. Running rich burns more fuel and you get black smoke from the tailpipe.

The optimum air/fuel changes with engine speed and load. At WOT, you actually want to see something like 12.5:1 or thereabouts. Adding forced induction, like a supercharger or a turbo changes everything; as does running ethanol which requires an air/fuel as rich as 8.5:1, or so.