AH64ID

I am installing my new exhaust this week and fiqured I would replace the O2 sensor as well. I tried the free route from toyota, but 160K is past 80K too far

I am not getting any codes, and all is running good (20.66 mpg my last tank with 33's), but with a new header, cat and muffler why not right.

Are 22RE's as picky with O2 sensors as they are spark plugs, i.e. do I need to run a specifc brand? I usually go OEM, but they arent cheap ($100). Bosch is 100 as well.

What to do?

Toyo4x4

I say "If it ain't broke, don't fix it". You won't know the difference if things are working correctly right now if you change it, only a lighter wallet. Wait until it throws a code.

midiwall

umm.... An O2 sensor will "wear out" and start throwing less and less of a voltage swing until it finally doesn't fall into spec and that's when you get a code.

It can also become clogged with carbon deposits, thus limiting the air flow to the elements and causing erradic readings.

You can get a decent idea if the sensor's working "okay" by dropping a cheap A/FR gauge on it and watching the swing. If it's "80-100% full deflection" (.2v->1.2v at idle) on a 2 second cycle, then you're probably okay. But if it's below 1v on the top end (which is what usually happens) then it should be replaced.

In lieu of an A/FR gauge, you can also use a needle based VOM (not a DMM) - the ballstics will be "off", but it'll be better than trying to watch a DMM spin through the numbers.


fwiw... my sensor right now is swinging short, I'm not throwing a code, and it's costing me a good 2mpg. Different engine, same principle.



AH... dunno about your rig, but on the 3.4L's were only asking for trouble if we don't use Denso (OEM) O2 sensors.

Toyo4x4

I stand corrected. I'm not technical enough to understand exactly what some of it means, I get the gist of it.

Elton

denso factory fit for $91 http://www.sparkplugs.com/more_info....77951&pid=1962
ngk factory fit for $85 http://www.sparkplugs.com/more_info....7951&pid=18020

midiwall

Denso -4052 from URD at $88.99 (plus shipping)
http://www.urdusa.com/product_info.p...s_id=430006000

regularguy412

Use Denso ONLY. No generics and definitely no Bosch. Two years ago I paid about $89 for my Denso.

Mike in AR

AH64ID

Thanks for all the info. There is a good chance that the sensor is 160K old, I'll probally buck up and get a new one.

ASU4runner

I used a generic brand and it's ran perfect for 100k miles. I'm at 200k now. I haven't seen a CEL since.

midiwall

Ummm... "that's really old".

AH64ID

When I pulled the fuel filter off last week it was a Toyota one.... I need to ask my father-inlaw if it was ever changed :-)

midiwall

! OMG !

WHORERUNNER

If your on a budget for the mean time just do what I did, pull the 02 out spray break cleaner and get a butane torch and light that puppy up. Let it cool and throw it back in.No more cel, it worked for my 93 Volvo 5banger w/5spd w/ 237,000 miles. then later down the road just get an oem when you have more $$$$.

Elton

if you dont wanna spend that much you could get a universal and splice it in i did it before and it worked great http://www.sparkplugs.com/more_info....77951&pid=1902

Nix_Toy

Hmm.. that's weird. The Denso I bought at sparkplugs.com was onlyu 45 bucks, including shipping...

05prerunner

ive bought a "denso" universal off of Ebay for $15 and didnt work but not sure if i had the wiring right. my connectors are cut off after getting burnt on the exhaust and i really want my gas mileage back so can anybody tell me which wire coming from the engine side is the + signal, - signal, and which 2 are heater wires. i know there is a brown and then the others are multicolored so if anybody knows or can check id GREATLY appreciate it.

rdharper

Mark, thanks for posting this... I was reading one of the other threads you are involved with, on attempting to control the input to the ECU... interesting. Are there PROM's in the ECU? Is there code available that we could play with?

Anyway, this thread is more at my level. Couple of questions:

1. Why does the O2 sensor cycle like that. I assume when it samples that it is sensing current, not voltage, with the lower voltage reading proportional to the current its reading. So the lower reading is reflective of what its actually using. But, of course, I don't know for sure.

2. Can you just hook an A/F meter directly on the O2 sensor and expect to get useful results? Any recommendations for that meter?

3. Have you guys mapped out the translation of the voltage readings to A/F readings for other than idle? If so, can you point me to a table or chart? Or a lean/rich table vs voltage would be all that's needed. If its linear with the ratio, maybe all I need to know is that .2 is rich, and I assume/guess the lower reading up near 0.8 would be lean?

4. Sparkplugs.com shows 2 O2 sensors for Ca (Denso OEM), one forward, one rear. Is that correct, are there two on the 3VZE ('94) Cal version. Is so, I assume both function the same voltage-wise?

Lastly, you are the guy that pointed me from another forum I was reading, to here. Thanks again for that.

midiwall

Richard!

Ya' know... when I kinda' took you to task in the other thread about reviving old stuff, I paused for a bit thinking "why do I know his name???". oops. HI! Welcome!

Anyway!

1. These can help as a backgrounder on O2 sensors:
   http://www.gnttype.org/techarea/ecms...O2sensors.html
   http://www.hondata.com/techclosed.html
   http://www.picotech.com/auto/lambda_sensor.html
   http://www.autohausaz.com/html/emiss...n_sensors.html
   
   
2. Yes, I run one like this. But the meter I have is ballistics compensated to soften the actual bounce. The downside of this is that it's slow to react when the ECU goes to open loop (WOT) which is where you can do the most good in tuning. I've also run this meter before, which is digital and reacts _right now_ to open loop readings. They pop up on eBay from time-time pretty cheap. I think I paid $50 for mine.
   
   
3. Check the link above in point #2. There's a chart there... It ain't linear.
   
   
4. Voltage wise, yes. But the sensor itself will have a reaction time and it's important to make sure you replace the respective sensor with the right one. Also, we've had a LOT of issues when straying from non-EOM sensors. Denso is OEM, so you'll be fine with them.

Hope that helps!

Sonofmayhem

I paid 30 online for a bosch and had no trouble w/ it but i wasnt throughing a code when i changed it. I was looking for better gas and it did help.

midiwall

That was in your 85/89? Are those heated sensors (4 wire)? The problems usually come from the heaters...