Oxygen Sensor Question

[Flifisher]

Hi....need some help with my rig. As you may have seen, I am doing many of my tune up things...and learning alot...thanks to you..My latest question is...What are the signs of a bad O2 sensor?? I am doing a tune up this weekend and would replace it...As far as I know, it has never been replaced...160K I am getting a rough idle which goes away after a while...leaving the check engine light on..

Thanks!!!!!!!!!!!

 

[clifhanger]

Hello Flifisher to better give you an understanding on your question let me give you some basic info on the O2 sensor. This unit is placed in the exhaust system to practicly read the mixture in the exhaust; it transforms this readings in a way that the ECU could understand it (0-1) binary system; this info is then taken by the ECU and used along with info from other sensors and in simple words, richen or lean the mixture of fuel and air. With this said; the O2 sensor operates much like a switch on-off (0-1) faster than the eye can blink and over time this cycle becomes weaker and for long, is undetected by the ECU, but you will experience higher fuel consumption that you might not even notice until is severe or the O2 finally causes the computer to trigger an O2 code. So to answer your question, unless you had problems with your engine where contaminants like oil or coolant went down the pipe you should replace it around 100k to 150k.at your discretion. O2's could be on the vehicle well into 200k. but that does not mean is operating efficiently. Remember, it becomes weak (it slows down). When replacing do not contaminate the probe. They usually come with a plastic cover. Good luck

 

[Baja Runner]

Pull that code. It will probably be a MAF code or O2 sensor code.

 

[mattman]

check this out:
4x4Wire - Tech: Time to Replace the O2 Sensor on your 3rd Gen Toyota?

 

[TheDurk]

Rough idle at start-up that goes away is more likely MAF. O₂ sensors only affect operation once engine has warmed up and the ECU has gone into closed loop. The primary inputs in open-loop (start-up) mode are the MAF and the temp sensor in the same unit. That said, 160K is a definitely time to change the front sensor; the rear one can stay until there is a code.

Never try to fix a MIL without knowing the code. Just a good way to waste money.

 

[runrunner]

I've been debating on replacing my O2 for some time. My neighbor has been an import tech for 20+ years and he said unless there is a check engine light, dont worry about it. I also spoke to a service manager at my local dealer, he too said not to replace it if I have wasnt having a check engine light.

Certainly conflicting information from what I read on the web. My mileage seems to suck, but its cold and were still in winter fuel mode. I seem to be averaging 15-16 mpgs, but that is 75% highway. I figure my tires, lift, and ARB bumper dont help, but I would assume that I could get better mpg's than that.

I just hit 170k and the problem is I dont have any service history on my truck. Has the O2 sensor been replaced? I have no idea...

 

[TheDurk]

I just hit 170k and the problem is I dont have any service history on my truck. Has the O2 sensor been replaced? I have no idea...

Look at the nuts. If they are original and you see any salt, they will be totally corroded. If it looks like they would actually come off in one piece with a wrench, the sensor is not that old. Does not apply in the desert. Should apply in OR.

 

[Flifisher]

You guys are great....I will let you know. Anyway of getting the code without going to a dealer??? I am extremely on a low budget...

Cheers!!!!

 

[98OzarksRunner]

You guys are great....I will let you know. Anyway of getting the code without going to a dealer??? I am extremely on a low budget...

Cheers!!!!

Go to an auto parts store, like O'Reilly's, ask to borrow a code scanner and go out to the parking lot and hook it up to the OBD II port. Instructions are easy and they will probably come out and do it for you if you ask them.

 

[brian2sun]

You guys are great....I will let you know. Anyway of getting the code without going to a dealer??? I am extremely on a low budget...

Cheers!!!!

Many parts stores like Autozone, O'Rielly's, Advance Auto (or whoever you have out there) will check the code for free for you. I know that O2 sensors can hurt fuel mileage and start going bad without throwing a code. I just got my engine rebuilt a couple months ago and was a little disappointed when my mpgs stayed around 13 avg. I had read that with a rebuild, it takes a few thousand miles to break the engine in and your mpgs may suck for the first few months.

But after about a month and a 1/2 and ~1500 miles (and still getting 13-14 on every tank), I got a CEL for my front O2. I changed it out (for a DENSO!!) and my mpgs have averaged 16.5 on the last 4 tanks since then. The lowest I got was 15.5 and the highest I got was 17.5. I live in the mountains too, so those numbers are pretty good IMO.

Also, those numbers are with my speedo/odo "calibrated" for my larger tires. I didn't actually calibrate it per say, but I used to have a Honda CR-V with stock tires which I compared it to. If I would travel 100 miles in my Honda, the same trip would register as 91.5 miles in my 4runner. So if I take my 4runner mileage and multiply it by 1.093, I get my true miles travelled (or at least close enough because my Honda was pretty accurate). That makes a big difference in calculating fuel mileage.

So if I travelled say 225 miles from a full tank to where my gas light comes on, and then it took 14.5 gallons to fill it back up, I'd get 15.5 mpgs... But now I take 225, multiply it by 1.093 which is 245.93. Then I divide that by 14.5 and my 15.5 mpgs is actually 17!!

 

[00_4runner]

check this out:
4x4Wire - Tech: Time to Replace the O2 Sensor on your 3rd Gen Toyota?

Quick question, how many o2 sensors on a 4runner? Approximate cost for parts? Mine is a2000 v6.

 

[runrunner]

Look at the nuts. If they are original and you see any salt, they will be totally corroded. If it looks like they would actually come off in one piece with a wrench, the sensor is not that old. Does not apply in the desert. Should apply in OR.

Well, they werent really corroded but nothing else on the truck really is either. It spent a lot of time in central Oregon.

Anyway, I spent a few minutes and crawed underneath and pulled it out. The nuts came off super easy. The O2 looked dirty, but it probably doesnt take long for that to happen.

The weird thing is, I cant cross reference the part # I found on it. Its a Denso 89463 35530. I went to Denso's website and the part # is not found.

 

[TheDurk]

Well, they werent really corroded but nothing else on the truck really is either. It spent a lot of time in central Oregon.

Anyway, I spent a few minutes and crawed underneath and pulled it out. The nuts came off super easy. The O2 looked dirty, but it probably doesnt take long for that to happen.

The weird thing is, I cant cross reference the part # I found on it. Its a Denso 89463 35530. I went to Denso's website and the part # is not found.

That is NOT a Denso part number. The sensor part numbers look like phone numbers: e.g. 234-4152. It's not Toyota either. Probably just a manufacturing code. Are you a Cali. or Federal? V6 or 4cyl. ?

 

[brian2sun]

That is NOT a Denso part number. The sensor part numbers look like phone numbers: e.g. 234-4152. It's not Toyota either. Probably just a manufacturing code. Are you a Cali. or Federal? V6 or 4cyl. ?

I just looked at the O2 sensor I replaced a couple weeks ago and it says:
TOYOTA
69465-
35360
ND 7900

Apparently the factory O2s aren't Denso. Either that or Toyota put their name on them but had Denso make them.? There are no other markings on my sensor either.

My O2 is different than yours, runrunner, but I would go to sparkplugs.com and plug your vehicle specs in. They ask whether or not it's a CA emissions which you can look under your hood and it will say CA or Federal. If they give more than one choice, either should work, but you may want to call them. Also, stay away from any of the cheaper "universal fit" ones, you'll have to splice wires.

 

[TheDurk]

I just looked at the O2 sensor I replaced a couple weeks ago and it says:
TOYOTA
69465-
35360
ND 7900

Apparently the factory O2s aren't Denso. Either that or Toyota put their name on them but had Denso make them.? There are no other markings on my sensor either.

You do realize that the letters ND probably stand for "Nippon Denso'? I don't think the sensors Denso sends to Toyota have the after-market part numbers on them. That doesn't mean Denso didn't make them. My factory Aisin water pump has only the Toyota part number on it, too.

If you look at the Denso page for your truck, you will see that DENSO thinks they are the OE manufacturer for those sensors.

http://www.densoaftermarket.com/catalog/catalog.php?part=o2sn

LIMITED, SR5
Engine: V6 (3.4L)
ID: 5VZFE
VIN: N

234-4162
Images Auto Trans; 4WD; DENSO is the O.E. Manufacturer N/A Upstream

 

[brian2sun]

You do realize that the letters ND probably stand for "Nippon Denso'? I don't think the sensors Denso sends to Toyota have the after-market part numbers on them. That doesn't mean Denso didn't make them. My factory Aisin water pump has only the Toyota part number on it, too.

If you look at the Denso page for your truck, you will see that DENSO thinks they are the OE manufacturer for those sensors.

DENSO Aftermarket Online Catalog Search | Vehicle Parts Search

LIMITED, SR5
Engine: V6 (3.4L)
ID: 5VZFE
VIN: N

Yes, I realize that ND probably does stand for Nippon Denso. However on the "ND" on mine, the last vertical line of the N is shared with the vertical line of the "D". So it's not even really an ND. And I agree, that definitely doesn't mean that Denso didn't made them - like I said,

Apparently the factory O2s aren't Denso. Either that or Toyota put their name on them but had Denso make them.?

But if Denso did make them, they definitely didn't put their part #s on them like you said - they used Toyota part #s instead as runrunner's and mine show. I don't know who made them for sure, but I have yet to see an original O2 sensor out of a 3rd gen that says "Denso" on it like any of the ones you buy aftermarket. It raises the question, but they did use Denso for most everything else sensor related so it makes the most sense.

 

[runrunner]

That is NOT a Denso part number. The sensor part numbers look like phone numbers: e.g. 234-4152. It's not Toyota either. Probably just a manufacturing code. Are you a Cali. or Federal? V6 or 4cyl. ?

It said DENSO on it. I just called the dealer and they couldnt find anything on the part # I gave them. They said the part #'s get updated regularly so I assume thats what happened. He mentioned that mine is probably original to the truck. The most current OEM part # is 89465-80034.

Get this, the dealer wants $164.29 for a new one! I advised that I can get one off the web for $60 and he didnt disagree. I inquired with him on when they should get replaced and I got the same answer. When the CEL comes on. He didnt flinch when I told him that if it is original it has 12 years/171k on it.

I cross referenced the one Toyota gave me and came up with 234-4162.

 

[Limited2K]

I just ordered a rear sensor off amazon and got it in today. The box is denso and the part number is 234-4153. I didn't check the numbers on the new sensor before i put it in, but the old sensor is OE or replacement OE from the PO. The old sensor reads "TOYOTA 89465-35350 DENSO 7981". The new sensor only said Denso and was a direct fit.

So both Toyota and Denso names are on my old sensor. I guess we're still trying to figure it out....

 

[brian2sun]

I just ordered a rear sensor off amazon and got it in today. The box is denso and the part number is 234-4153. I didn't check the numbers on the new sensor before i put it in, but the old sensor is OE or replacement OE from the PO. The old sensor reads "TOYOTA 89465-35350 DENSO 7981". The new sensor only said Denso and was a direct fit.

So both Toyota and Denso names are on my old sensor. I guess we're still trying to figure it out....

Yeah I'm pretty sure Denso made all the OEM O2s, the part numbers are just screwy.

 

[TheDurk]

Yes, I realize that ND probably does stand for Nippon Denso. However on the "ND" on mine, the last vertical line of the N is shared with the vertical line of the "D". So it's not even really an ND.

Uhhh, that's their old logo....you are a tough sell, my friend.

The way I do it is to get the Toyota part number off Toyodiy.com and put that into the cross-reference tab of the Denso aftermarket catalog. That gets you the correct Denso number. Then buy that item on Amazon--or anywhere else I can find a good price, but lately it's always Amazon. There are some mistakes in the Denso application list, but so far the cross-reference from the Toyota number seems to work.