k_southman

I was speaking to a former toyota mechanic today and he told me that the O2 sensors for a 99-02 3.4L 4Runner will be the same no matter where you buy it.

They are all made from from the same place and will all have the same NP part # on them no matter how they are repackaged (bosch, toyota, NKG, etc.) Could this possibly be true?? I don't belive it but I figured that someone must have looked into it before.

kevin444

i doubt it, i heard bosch has a high return rate. so no bueno

ewong

there are some differences
--one wire
-- three wire (heated)
-- WB EGO (aka Honda)

and then of course the packaging (aka toyota bolt on flange vs screw in type)
as well as the connector (or lack there of)

On my VW I use the generic one with bare wires and solder it on.. cheaper ($35 vs say $90)

icerunner

BTW: HE said 99' to 02' 4RUNNER ...
It totally makes sence to me and is probably 100% the case.
yea there may be different wiring configerations but essentially there all the the same frickin part.

o2 sensors are not too complicated....but they are expensive!

AND WHY IS SUCH A SIMPLE PART SO EXPENSIVE?????

Manufacturers and dealers are making a KILLING on this very simple stupid part
thats why.

AND you need to replace them (quantity of 2) every 75 to 80K at $125.00 each!!!!!

spend 250.00 plus labour or your MPG goes down the drain

( AND they do go bad with NO check engine light)

AND there is Labour involved because if you live in the midwest the road salt rusts them to the fricken tail pipe and they have to be torched off. Or you WILL lose a whole fricken knuckle trying to removethe rusted o2 sensor nut (as I almost did)

god darn fricken o2 sensors

ewong

IMHO the cost is maily for the connector...

There's a Mustang part thats a typical 4 wire (2 grounds) that comes witn a short pigtail of bare wire and its like $40 instead of $120. So if you are willing to solder (or make an adapter harness to say univeral type connector) - then you can same some $$$

Basically the same thing that blew the WBEGO market open in the late 1990s... people discoverd that an OEM Honda part was really a $$$$ WBEGO part... and then a bunch of DIY make a controller for it. Its why all the WBEGO's are about the same price now - the controller circuitry was published to the web and no one could "hide" it...

k_southman

I was talking about the 99-02 direct replacement O2 sensors...not the generic DIY ones. Does anyone have part #'s off the actual sensor so we could do compare?

icerunner

Southman,
I may just prove my self wrong on this one.
I have my Denso "1st time fit" o2 sensor that I just ordered from undergog racing developement for $95.00 for my 99' v6 4runner auto 49state federal emmissions NOTE this is for "before" the calitilic converter


This seems heavy duty and really well built and states features on the box on the box Stainless steel housing, porus PTFE filter, aluminum oxide trap layer double protetion cover.

Here we go:

DENSO 42140 01J25 "assembled in USA"

surf4runner

im at 133k and AFAIK they have never been changed.
still getting 20mpg. havent done the 90k service either. mostly cuz im poor.

recommendations are just that.
the dealers make $$$ scaring customers into something they dont need (yet) or understand

k_southman

Is that off the box or off the sensor body? I heard that the part #'s on the sensor bodys should match no matter where they come from...

I think I am going to order one from toyota and see for myself.

ScubaDuck

Ok, just changed my front 02 sensor (99 4Runner, 3.4l cali emissions package) at 116k. (Yes, really an A/F Ratio sensor)
Here is the sensor I removed:

Hard to read on the photo, but the sensor says (engraved/painted on the sensor):
Toyota
89467
-35010
DENSO 0050

then below the crimp:
12T1S

The new sensor (DENSO, 1st Time Fit, purchased from URD, product No. 234-9002):


Again, hard to read, but in the same writing on the sensor:
DENSO
Japan
3420
03H07

It's possible that NKG makes Denso sensors, but if they do, they have to engrave the Denso ones separately. Hope this helps-

-Scubaduck

pius222

I have a 99 4Runner SR5 4WD Auto, and the MPG is pretty bad, I get around 270 miles on the tank, that calculated to about 14.8MPG. I searched on how to improve MPG and here I am about the Oxygen Sensor.

The truck has about 135000 miles on it, do I need to replace the O2 sensor? What part # should I get? When I do a search, it has a list of option showed up, and it has "before" or "after" Cat. converter, what is that? I don't know whether my truck is before or after. Thanks.

Adam F

your math is off. you have a 17 gallon tank, and if you fill up when the low fuel light comes on, you put in about 15.5-16 gallons. 270/16= 16.8mpg thats about average for city driving.

rimpainter.com

It's not necessary to replace them in twos (unless you are referring to some special CA set-up that I don't know about (sorry if that's what you are talking about). The after-cat 02 sensor only takes on about 10% of non-essential "sniffing" duty. The information you were given was probably just a ploy to get people to spend more $.

The pre-cat sensor is the one we should be concerned with and thus far it seems URD has the best deal on them.

The jury is still out on exactly when to replace it though. Do we wait for the CEL, or just base the decision on mpg? I don't know. I track my mpg religiously on Excel and I haven't seen any drop in mpg that would lead me to believe the 02 sensor was going out. I am running the original 02 sensor and have 98K miles.

pius222

I thought 3rd gen has a 18.5/g tank. that's how I come up with the MPG.

Beartracker

You can not figure your gas mileage by how far you travel on a tank full of gas. You will be way off. You need to calculate "miles per gallon" and not miles per tank full.Mike

Roadtripr

pius222 how much do you regularly fill up? Yes the tank can hold 18.5 gallons but the light usually comes on when 4 gallons are left in the tank. As Beartracker says you have calculate miles per gallon using your odometer and how much you filled up (eaample 270miles on 15 gallons = 18mpg).

Other than that check your tire pressure, airfilter and don't drive with a lead foot and see what you milage is. Did you milage drop recently or has it always been bad? (I always get lower milage in the winter months)

ScubaDuck

Pious222-

A couple of thoughts for you:
1) you are correct that '99s have an 18.5 tank, but that still won't give you an accurate MPG calculation. FYI- My low fuel light comes on with approx 5.5 gallons in the tank due to a common fuel gauge glitch common in 99 (and I think 2000) 4runners. Thus, if you have this glitch and are filling up when the light comes on, you could be using only 13 gallons of your 18.5 gallon tank. As stated above, to get accurate readings, you need to reset your trip meter when you fill up, then divide miles by the amount you put in on your next fill up.

2) To determine what part #s you need, you first need to know if your truck has California emmissions package or the 49 state package. You can tell by crawling under your truck and looking at the exhaust, or probably from a sticker under your hood. I am told that if there are 2 cats, then you have the CA package. Next, go to underdog racing development website(www.urdusa.com) and look at their list to see what you need.

3) IMHO, O2 sensors are way too expensive to be replacing "in case" it has gone bad. I only replaced mine because I got a CEL which indicated that it (Sensor 1, the one before the Cats) was malfunctioning. I have no idea which one you would want to replace if you are just guessing.

Good luck-

Scubaduck

Ebbsnflows

Sorry to get sidetracked of original topic...but regarding fuel economy....don't forget to remove the MAF and clean the electrical element with Electronics spray cleaner (at RadioShak). About every 12-15k miles I notice my Fuel economy slowly begin dropping from 22 mpg to 18 mpg. Each time, I remove the MAF and clean the wire filament. Voila'....I gain 3-4 mpg immediately.

BTW...I also have the Boat deck mod and K&N filter.

Now back on topic....I have 107k on my 00' 4runner...so I guess I'll be in the market for new 02 sensors soon. Underdog racing is the cheapest place to get them?

icerunner

Everyone, I have notice a solid 2-3 MPG increase after changing my before cat o2 sensor with a "denso first time fit" o2 sensor from URD. I didn't replace the after cat o2 sensor due to the cost. I now get about 18 MPG.

MAN, I sound like a stupid "infomercial".

Southman: yes that part # above was from the sensor casing itself.

Ebsanflow:URD all the way!!! i spent about 95.00 total (for the o2 sensor before the catilitic converter) now getting the nuts off the little bastard on the tail pipe is a different story all together.