theryanator

Midi-wall,

Thanks, I will go ahead and order an O2 sensor...I have waited on that simply because it is something I am not going to be able to replace on my own. I have tried to get the old one off and the bolts that hold it down are corroded so badly I cannot even get a grip on it to unscrew it from the pegs on the exhaust pipe...darn the cold, salty, crappy Chicago winter weather!

Thus, I will order the part (about 1/2 price what the dealer quoted me) and take it and the truck to my mechanic, he said he can probably get the old one off with a torch and some gentle prodding.

Thanks!

midiwall

Hey Ryan...

Check out this thread: Replaced front O2: +4 mpg

DrummerDaveB

Ryanator!

You've never answered the question: Are you running stock size tires?

IF you're running 33's or something, then your mileage isnt really surprising.

What do you have on your rig?

86 TurboSR5

1986 toyota 4 cyl turbo. 31+mpg highway. With camper and 400 lbs in truck All stock. Truck flys with the turbo.

86 TurboSR5

I like to take mileage in this x-cab so i know quickly something is wrong if it drops off.

theryanator

DrummerDave -

I am running the stock tires that come on the 99 runner sr5, I believe they are 30 inch. How is the mileage in your opinion based on that tire size? I got 18.5 on the highway last week, however on the street I am still averaging 12.5-13.

theryanator

So the last three tanks I have gotten between 225 and 230 miles. about 30% of that driving has been highway. It comes out to between 16.5 to 17.2 milesper gallon. Perhaps the improvement from 12 mpg is from switch from winter gas/a bit more highway driving/replaced the air filter which was not clogged, but was very heavy and much more dense than the filter I replaced it with.

I am debating whether at this mileage I should be satisfied, or if I should still drop the $400 approx. to take it to the mechanic to have the 02 replaced, when I dont even know if that could be a problem. Should I be content with the mileage or see if I can get better and get the 02 replaced even with 16.5 average or so per gallon? THoughts, comments?

mt_goat

$400 How many O2 sensors do you have? I could replace 4 for that price.

theryanator

Well, I would do it myself as well. I tried a while back to take the 02 off just to see how badly it was corroded, but could not because the bolts that hold it on the piping were rusted so badly they will need to be torched to get them off...hence I will have to take it to my mechanic. $75.00 an hour for labor (2 hours about he said) plus the cost of the part $170.00 all rolled up with tax and all is a bit under $400.

Ideally I would like to order the 02 sensor myself to avoid he mechanic mark up, and just give it to him to install once he loosens the bolts on the old one. However I am not sure which one to get as I was told by my dealership that for my year and model (1999 sr5) there are actually 3 DIFFERENT possibilities for the forward 02 sensor based on the three different manufacturers they were using that year for those parts. Is this true? Anyone know if that is valid? I found this one on

http://www.urdusa.com/Merchant2/merc...Category_Code=

It said I needed this one for the front 02 I am looking to replace

1999 49 State auto V6 4Runner; Front = 234-4161

Would this be a "one size fits all" sensor if in fact what the dealership told me is true that there are THREE DIFFERENT possibilities?

I am kind of in a quandry here in regards to that, if that is not true, I will probably order the 02 sensor online and give it my mech. and save $70 .

Thanks!

mt_goat

I'd get a second estimate on that. I bet a good muffler shop could replace the whole O2 bung for less labor than that.

On the part # make sure the dealer looks it up by your vin #, and not the short cut way of year, make & model. That should give you only one #, but double check that by calling 3 or 4 dealers. That will also give you a chance to compare prices at the different dealers. Here are a few deep discount dealers to call:

https://www.1sttoyotaparts.com/tollfree.html
http://www.trademotion.com/partlocat...?siteid=214074
http://www.toyota-parts.com/

Be sure to check shipping price too. Usually what you save on sales tax (no sales tax on out of state shipping) just about makes up for the shipping cost.

DrummerDaveB

You could take it to the mechanic, have him remove the bolts, and replace them with new ones.
Then you take it home, pull the O2 sensor, then just clean it as best you can. If it's a little clogged that could solve your issue.
Then drive it, and see what happens.
IF your mileage is still low, and you decide to replace the sensor, you could order a new one then.

For stock tires, that's a bit low yet for hwy.

theryanator

Alright!!! PB BLASTER ROCKS!

I tried WD-40 and other things to loosen the bolts to no avail...a little PB BLASTER and 3 minutes those bolts came off in a jiff. Anyone by chance know what size bolts those are on the front 02 in a 99 runner?

So I cleaned the sensor, when I was finished it was still black (more burnt looking) but when I rubbed my thumb on it my thumb came away clean with no soot...does that sound right? Since it still is black in color though should I assume it is burnt out and just replace it? I know the new ones are shiny aluminum in color. One thing I did differently was instead of using acetone I used brake cleaner and some electronic cleaner on it due to the strong urging of the guy at the Autozone who pleaded with me NOT to use acetone as it would leave a residue...So I figured I would give the other cleaner a try for now...should those alternatives have done the trick cleaning wise?

Thanks a lot for all your help! If it was not for you I would have had to pay at least $75.00 for labor at my mechanic to have him get the bolts off for me.

midiwall

Yeup!

Congrats!

theryanator

Yeah, the stuff is great...it looks gimmicky when you see it at first...like a "as seen on tv" commercial, but it is worth its weight in gold.

Still not sure what to do with my 02 sensor is it junk since it looks charred in color??

AgRunner06

Replace your O2 and pull the efi fuse for 10 mins. That way your computer can relearn everything. That should fix your problem.

midiwall

I'm confused... So, did you replace the O2 with a new one or did you pull it, clean it with various stuff, and put it back?

The black is "okay" in the sense that it doesn't mean it's shot, those are normal carbon deposits that come from the exhaust. Testing an O2 sensor requires a volt meter, but it's only a "go/no go" test, it won't tell you how accurate it is. The accuracy of an O2 sensor will degrade over time because of how it works. The elements that react with oxygen content wear off of the probes and the amount of voltage it produces will be reduced. Also, carbon deposits will form on the electrodes blocking air from getting to them, this is why cleaning works.

Considering all the talking that folks have done with you in the past couple of months, I think we'd all suggest that you REPLACE the O2 sensor, it's your best bet. But... you also have a good chance of the present O2 sensor getting a 2nd lease on life by cleaning it with acetone.

Yes, acetone is harsh stuff - that's the point; you're trying to dissolve the carbon deposits on the electrodes. The brake cleaner and electronics cleaner did little to do this... Electronics cleaner of years gone buy was nice and nasty, but the stuff sold over-the-counter today is lame.


So... if you haven't bought a new sensor yet, then a can of acetone is cheaper than a new sensor. If you've already bought a new sensor, then put it in, and start soaking the old one. That'll give you a backup and let you swap between them as you clean the new one in 20,000 miles or so.


And... like Ag said, once you put in a new one or put in a cleaned one, pulle the EFI fuse for a couple of minutes (my ECU resets within 10 seconds) and let it relearn about your engine.

theryanator

Wow, Midi and everyone else, I really DO appreciate all your input. As you pointed out this has been a couple month thread as I just dont have a ton of spare time to work on it, but when I do it has been great to have you all here with your help and experience. I will be buying acetone today and cleaning the 02 and place an order for a new one.

Is the EFI easily located in the fuse box under the hood?

Thanks again everyone!

timk2915

Try having your injectors cleaned and ballanced....... I've heard good things and I'm going to try it myself in a couple weeks.

midiwall

Yeup, I think the under-hood of our trucks is similar... Just behind the battery is a long box with a number of rectangular graphics on it, this is one of the fuse boxes (there's another one in front of your left knee as you sit in the driver's seat). Pop the top on that box, and you'll see a number of fuses. Using the graphic on the top, locate the one that says "EFI", mine's the 3rd one up from "the battery" ("bottom") on the left side. Pull it, wait a bit (people will tell you to wait anywhere from 10 seconds to 10 minutes) and then put it back in.

The truck _will_ run differently after doing this, you won't know if it's running "better" or "worse" for 50 miles or more of _mixed_ driving (stop & go through highway).

Don't look at your MPG for the remainder of the tank that you're on, wait for the next full tank.


Good luck!

midiwall

I agree that this can do a world of good, but in working with Ryan for the past couple of months, I don't know if I want to walk him through pulling the intake, the plenum, the fuel rail, the injectors, getting them done, and then getting it all back together.

And then, having him look into the cost to get someone else to do this may send him into a heart attack...