And where are they located if there is more than one, i know theres one at the cat.

 

2 total.

Primary - Before the cat in the exhaust manifold
Secondary - In the cat

 

well ****, you mean i got to buy two. or is one more likely to get fowled than the other. i bought one thats the 4 wire splice kind. should i buy another?

also my cat is entirely full of carbon cuz i blow out a foot long line of carbon/water mix when i start my car in the mornings

 

bump for quick response

 

b

do i need 2 or not

 

which CEL are you getting? (I assume that's why you're replacing the O2 sensor)

the front O2 is used to run the engine.
the one in the cat is to check the condition of the cat.

 

im not sure about CEL...explain that to me


The one in the car, is there a code thrown for the cat or is it by visual inspection of that o2 sensor

I would like to replace the one that runs the engine....

 

ok got it...no im not replacing based off engine code. I'm replacing because i get **** for gas milage ...25mpg and its probably fucked from the carbon smoke when i seafoamed

 

The one in the cat, is there a code thrown for the cat or is it by visual inspection of that o2 sensor

I would like to replace the one that runs the engine.... so basically the one in the cat doesnt matter?=/

BUMP

 

the one in the cat can be removed and replaced by an O2 simulator if you want to run catless.

there are different codes for the primary (front) O2 and secondary (rear) O2.

I'm curious... does your check engine light turn on when you start the car?

 

but you running with cat or not? if you run with cat and your car shor Check engine light.. it would can to be alot things.. it would can to be that you have the O2 bad or too you would can to clean your cat cuz it's possible that be a bit obstructted

 

the check engine light comes on for a sec, but it doesnt stay on. I am not running catless and dont plan on it.

so all i need is a new o2 for the front and an o2 sim for the cat ?

 

i think only second.

 

there is no point in changing o2 sensors if you dont have any codes. it could be other things in your motor that is causing it to get shitty gas milage. obd-2 is really good onboard diagnostics and will let you know if your o2 is going bad or if the cat is going bad. so try and find the source of the problem before you go changing the o2 sensors. if you have access to a digital oscilloscope, you can check yourself to see if the o2 is still good. it should range from .250V-.850V in a 2 milisec frame

 

just get a tune up, clean injectors, replace plugs, fuel filter, etc

 

ok already done the easy ****, clean injectors, plugs, filters, oil.

I dont have obd2. I have a p30 OBD1, conversion down. My dash isnt hooked up properly to the ecu, so it wouldnt tell me if i had a code for a lot of things anyway.

 

and an o2 sensor is only 24 dollars, and its been 40k miles, so why not?

 

could be a dirty/clogged air filter. short ram intakes give you shitty gas milage also. and the obd-1 ecu you are running might be chipped and runs rich, thus wasting fuel. there are many things, but you dont clearly state what is done to the car so people on here cant help you out

 

you're OBD1? then you don't care at all about the second O2 sensor. It's not used by the P30 at all.
a four-wire O2 for $24??? what kind of hook up do you have? last I checked the lowest aftermarket was $75.