The previous owner of my 4runner got the catalytic converter stolen, so rather than replacing it, he threw in a straight pipe.

After looking at the pipe, I noticed there are 2 o2 sensors - one which is still in the pipe (a pre-cat sensor), and one that is just coiled around the frame (the post-cat sensor, which he didn't install into the straight pipe)

So - my questions are:

-is this a California truck?
-how many o2 sensors TOTAL are on this thing, and besides the pre and post cat sensors, and where are they at?

This is what I plan on replacing the straight pipe with:
http://www.partstrain.com/store/deta...EAST70421.html

...and the 2 o2 sensors (check engine light is on...)
http://www.partstrain.com/store/deta...USOS-4000.html

Thanks...

Ben

 

There are two o2 sensors

 

Are there always 2 o2 sensors, or only on California models?

Ben

 

after 89 i belive they all started to have 2 o2 sensors.. 4runners and pickups.

 

My 94 runner only has 1

 

There is only one O2 sensor on OBD1 engines, which are anything pre-95.5 (3.4L) for Toyota trucks & 4Runners.

 

Right, I saw a 94 yesterday with only 1. I'm so confused by this? This is definitely a 1995 3.0.

Which is why I ask: Is this a California model? I know their emissions are different.

 

Innervision, is it before or after the cat converter? I'm guessing before?

 

The sensor is before the cat. The number of sensors is the same for North American vehicles.

The Toyota EPC only shows one O2 sensor for the '95 4Runner.

 

Yeah I was pretty unsure about that too. My 1994 only has 1 O2 sensor and its a CA emissions. The giveaway was that there is an EGR temp sensor.

 

It is before the cat. I just replaced it a month ago when the cel came on. The 2 sensor setup came with in 1996

 

My understanding is that ALL California 1995 trucks have two O2 sensors; I believe that the Forerunner is the same. It is also my understanding that most non-California trucks only have one, but I'm not as sure on that.

My 1994 truck has two sensors.

Rockauto believes that 1995 California trucks require two.

(If you care, the second sensor allows the ECM to monitor whether the Catalytic converter has failed. As the first sensor signal swings up and down, the second one should do nothing. If it starts swinging in time, the cat isn't doing anything.)

The sensor you're looking at is a "universal," meaning that you're going to have to leave an amateur splice down there with all the slush and dirt. Rockauto has the "correct" part with the connector included, but it costs about twice as much. Something to think about. The Cat you're looking at is a non-California model, so you may have a problem with it fitting. I don't know how much of your original piping is left, or if you care.

 

Look at the sticker stuck to the underside of the hood. That will be the definitive answer. Or you might try decoding the VIN with 4Crawlers chart.

 

My '94 22re pickup has two. It's a Cali emissions truck. One pre-cat, one post-cat.

 

I'm alright with splicing and sealing on my own...the whole pipe is messed anyway, since the last owner just threw in a straight pipe. In uninterested in paying premium to get the original setup. So long the cat and 2 sensors are in place and the CEL turns off and my engine runs NORMAL again...I'm cool. So I'm going to be cutting and welding a cat into the straight pipe he put in. This cat will fit just fine.

 

Yup, under the hood just revealed it sure is a California model. So the pre-1996 with 2 must be a Cali emissions thing...

 

crap i was wrong