New 02 Sensors = Mileage Increase

[XXXR]

I'll be interested in the stink issue - you are the only one to bring it up.

I was watching a show the other night where they were going to town on a Corvette's exhaust. The dude mentioned that the car "stunk" and that it was most likely the O2's but could be have been the cats. I'm hoping for just the O2's... well see. just got em last night and I'll install this weekend.

$91 for the front, $91 for the rear FYI... went with the Walkers that are Denso's except the plates are separate.

 

[CJF]

I'll install this weekend.

Hit the bolts with PB Blaster NOW.

Good luck,

Curtis

 

[XXXR]

So here’s the update. Results will vary.
So, I crawled under there, thinking this was to be a 15 minute job... try 2 hours. I wish I had caught Curtis's suggestion before I went at it... because I had a HELL of a time getting the rear nuts off. I finally had to pull out the Dremel tool which was interesting as well, as the O2 shield makes things super tight. Anyway, I got the rear off and started on the front. The front was easy, as the nuts were pretty much rusted off, allowing for a non existent seal. I cleaned both faces by scraping them with a blade, then some fine sand paper until clean.

Well, installing the new ones was super easy after this, and I'll tell you what... DRASTIC improvement. She is peppier off the line and takes much less pedal onto the freeway now. The "STINK" now smells like exhaust, and dissipates as she warms up. I had the wife take it for a spin to make sure this wasn't just a "mental anguish" result. She verified it was stronger pull.

I'm looking forward to better gas mileage, but the response improvement alone was worth the 180 bucks.

Again, results will vary, as the front sensor was obviously failing due to the gasket/seal corrosion. But I would suggest that you at least inspect them, as the damage was not apparent until I removed the O2 itself.

 

[tarbe]

Wow, thanks Scott.

I'll second that!

 

[smokethedog]

what size are the nuts for the O2 snesors? I'm getting ready to replace my front sensor, nuts will have to be replaced as well due to rust.
thanks

 

[XXXR]

what size are the nuts for the O2 snesors? I'm getting ready to replace my front sensor, nuts will have to be replaced as well due to rust.
thanks

Eh... I believe I was using a 12mm, but I can't tell you for sure. None of my box wrenches really fit well and the socket was the same. The rust had really eaten the nut edges. Sorry. Just be ready with a splitter or buy a Dremel.

Oh yeah, and I would suggest you change both of the sensors if you got em. Expensive, but they seem to wear out at the same rate. total shipped was 181.00.

 

[Rogorn]

380 bucks A PIECE?....


Toyota's published LIST price is $145.34 each. If you can find them under the pair part number a SET is $264.46.

Did the guy give you the courtisy of wearing a mask and pointing his six-shooter at you?.......

<ROFLMAO>

I'm not at all surprised at the differences. I've had on-going bad advice and practice from them for over 15 years. At one point, for warranty service, we got to where we drove an extra 40 miles to have service done at a competing location.

Maybe I should relay the story about them charging me $1800 in luxury tax and then six months later I found out the vehicle was exempt from the tax (a weight issue or something). Only turning them in to the IRS for tax collection fraud was I able to get my $$ back. Something about it being illegal to falesly collect a tax and then compounding it by not depositing that tax with the IRS. Go figure...

Oh well, time for

And another example of how the Internet is slowly changing market dynamics.

 

[MikeB]

My mileage had been 14 MPG or a little less for the past few thousand miles after always being a very consistent 15 previously. I replaced both O2 sensors with Denso 234-4153 and 234-4157 from http://sparkplugs.com/ and I'm back to 15.5 on the first full tank fill up. The aftermarket Denso sensors sure look EXACTLY like what came as orginal equipment. These are the plug and play sensors, no splicing. I have since seen these Denso sensors for as little as $65 - $70 plus reasonable shipping on eBay.

The nuts looked like new. Loosened 1/2 turn with a box end wrench then spun them off with my fingers.

 

[RavenTai]

I was curious, if my math is right, and assuming the trend from just a single tank holds, @ $2.50 a gallon you will break even surprisingly quickly, 11K miles, after that you will be saving money.

Somebody double check my math.

Gas ~$2.50
14 vs 15.5
187.09 For sensors (+ shipping?) (isn’t that about what Dan gets them to us for?)

So 14MPG is 17.8571429 cents/mile (minus) 15.5 is 16.1290323 cents /mile (=) a savings of 01.7281106 cents /mile.

$187.09 / .017281106 dollars per mile = 10,826. Miles

 

[scottm]

Anyone replacing these please gather as much before/after emissions/mileage data as possible.

Hmm, shoulda started on this thread instead of starting a new one. I had the same luck with that website my brother had, will try it again later when I have more time to wait. Here's my before data, what other data would be helpful? I can graph most anything. Mileage will be difficult, we don't drive the 80 much any more, I ride to work, which I'm about to do.
https://forum.ih8mud.com/showthread.php?t=83668
https://forum.ih8mud.com/attachment.php?attachmentid=61925&stc=1&d=1142303486

 

[scottm]

Odd, but O2 sensor #2 seems to be working now. Either it's faililng intermittently, or it only works when the vehicle is up to temp? The code seemed to imply it was the O2 heater failing, so perhaps it's a temp thing. This was after my wife drove it around a bit, last time was from a cold garage with some time to heat up. This time coolant temp was steady around 190+F.

No luck with the sparkplug place website, I let the computer sit overnight waiting for a response for O2 sensors on a '97 LC. I'll try the phone I guess.

 

[scottm]

Here's a little more active sensor shot, hope my cat's ok! The second one is idling at a stop sign, then pulling away. The top-right graph is changed to Long Term Fuel Trim, never saw any movement on Short Term Fuel Trim (Sensor 2).

 

[Gumby]

I just replaced both of mine. Better performance all around. I had had a cat inefficience code and was recently getting a front O2 code on occasion.

Now this is a PM I can get behind.


I did have a problem with getting the wrong front the first time. There was a minor difference in the configuration of the plug. Maybe because it's a 95?

 

[scottm]

I checked the recommended sites, but Autozone has universal O2 sensors listed for only a couple bucks more, and one a Bosch. Today I stopped in and bought the one they had in stock: Bosch 15728, a universal sensor for the front, $64.99. The Denso front universal sensor is about the same price, it's the same universal unit listed for front or back. Bosch lists a different universal sensor for the rear for a whole lot more $. The Bosch I bought has nice, waterproof connectors that go on the wire after cutting and stripping to length. I'm curious if the front Bosch is basically the same as the rear, the old ones look the same externally so far, but I don't have them off yet.

I tried removing my rear sensor, got one nut off but will buy a Bolt-Out set tomorrow to get the other off. All these nuts look badly eroded, I tried hammering on a few different sockets with little success. PB Blaster and a MAPP gas torch had little effect since I couldn't grip them. They're M8x1.25 thread, so they should be 13mm hex, but they're much smaller than that now. I'll order some 316 stainless deep nuts tomorrow for the install. They come in boxes of 50, so that'll be another part to send off to my bro for his cruiser. When I get them all off I'll snap some pics of the old and new.

 

[cruiserman]

My mileage had been 14 MPG or a little less for the past few thousand miles after always being a very consistent 15 previously. I replaced both O2 sensors with Denso 234-4153 and 234-4157 from http://sparkplugs.com/ and I'm back to 15.5 on the first full tank fill up. The aftermarket Denso sensors sure look EXACTLY like what came as orginal equipment. These are the plug and play sensors, no splicing. I have since seen these Denso sensors for as little as $65 - $70 plus reasonable shipping on eBay.

The nuts looked like new. Loosened 1/2 turn with a box end wrench then spun them off with my fingers.

Got a part number for '93 to '94?

 

[scottm]

Here are my old O2 sensors and the new $65 Bosch sensor from Autozone. I don't see any difference in the original front and rear sensors, except the rear has a longer wire. Anyone have any thoughts on possible internal differences? Is anyone still reading these? I'm going to get another Bosch universal front sensor for the rear, unless someone can tell my why I shouldn't. My wife's birthday is tomorrow, so I may not have results tomorrow night. Oh, the Bolt-Outs are half-off at my local Craftsman store, lucky me! They worked great, but I needed my flex-head Gear-wrench on it for a front nut. Not much corrosion under the truck, and the threads all look excellent, but the nuts were just globs of rust.

 

[Beast II]

Have you noticed any notable increase in gas mileage ?

 

[scottm]

Yeah, I'm getting 25mpg driving my old Audi while the cruiser sits! I highly recommend this strategy. I'll put the new sensors in tonight. I'll run graphs of sensor performance, but I don't drive it much to get mileage numbers. I'll probably drive it to O'Hare next week, maybe I'll have mileage numbers when I get back from Florida. I considered doing HP, torque, 0-60 runs with the software to compare before and after, but apparently the O2 sensors are inop during full-throttle operations.

 

[scottm]

Ok, pretty dead thread, but just in case someone does a search here's my results: Two Bosch universal O2 sensors from Autozone, with one-year warranty, $130. The truck feels a bit smoother in idle and driving. These came with a pretty nice waterproof connector. I had to trim the splash shield that mounts on the rear sensor just a bit to get the hex base of the new sensor to clear. I just filed it by hand, not much really. I cleaned the studs on the exhaust with a thread repair die, coated them with copper anti-sieze, and used new, 316 stainless washers and nuts. The old gaskets had become one with the exhaust, no way to get them off, I left them and added the new ones.

One important thing I'll offer is that the new sensors are a lot smaller, and will restrict the exhaust flow much less. I'd say the old ones must have taken at least a third of the area of the pipe, maybe half. The new ones are significantly smaller, nearly half the size. Ten years of progress in sensor technology I guess. I didn't measure the new ones or do the geometry, but I took a year of aero engineering and this looks significant to me.

The sensor graphs look much smoother now, larger and slower sweeps. The second shot is pulling away from a stop, dramatically different than before.

 

[scottm]

Here's the waterproof connector. The instructions say to strip the ends, then poke them into the box and throught the tight, rubber washers. Better to strip the ends after poking them through.