oxygen sensor questions

[cre]

Originally Posted by supraluver4life

alright i will look into getting one of those. um does it just hook right up or so i have to do a bunch of wiring?

If you're just installing it along side your existing system (not intent on wiring it in to replace the narrow band) then all you need to do it run the wires to where they need to be and connect power and ground. You will need to have another bung for the sensor to screw into welded into the exhaust down pipe.

Originally Posted by supraluver4life

and does it do anything performance wise?

Not by itself. The wide band is a diagnostic tool; the same as the narrow band. Some systems (such as the stock ECU (TCCS), certain piggybacks and all stand alone EMS's) use the data received from an oxygen sensor to monitor exhaust gasses and adjust fueling and other related functions in order to maintain a specific threshold.

The main difference between a wide band and narrow band oxygen sensor is that a narrowband sensor is really only able to read a very small area. It reads for Lambda or stoichiometric: an optimal burn. With gasoline this represents 14.7 parts of air to every 1 part of gasoline. The problem with narrow band sensors is that as you get away from Lambda the sensor isn't capable of reading anything other than "rich" or "lean". A narrow band sensor is more of a switch; rich, optimal, lean.... that's all. The ECU adjusts fueling to keep this stoichiometric mixture by adding and removing fuel as the narrow band's signal bounces back and forth from rich to lean very rapidly (That's also why AFR gauges don't serve any purpose with a narrow band sensor).

A wide band can read a great deal of the spectrum and report conditions outside of Lambda with a great deal of accuracy; Unfortunately, the sensors are more expensive, delicate and require more hardware to control and calibrate.

Here is a *decent* article on oxygen sensors on Wikipedia.

Originally Posted by supraluver4life

and also do you know how i can test my oxygen sensor? cuz im getting the error code that says it aint working. thanx for your help

Whenever you're asking for help with something post any error codes you may have (whether you think they're related or not). What is the error code you've received?

Oxygen Sensor Testing:
http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=119
You DO need an analog meter to test it.

Originally Posted by supraluver4life

oh and thank you so much for your help i always appreciate someone who is just there to help people in need

Sure thing.

Do me a favor, please; work on your capitalization, punctuation and grammar... it makes it easier for me to help you if I don't have to reread posts.

[supraluver4life]

Alright, and one more thing. you said another bung would have to be welded to the exhaust for the oxygen sensor to screw into, where exactly does that go, i.e. on downpipe? after downpipe? after test pipe?
Do i have to put another oxygen sensor in or can i just replace the stock sensor?

[cre]

I killed a WB sensor by placing to too close to the manifold on my N/A. A lot of people have no problem placing their WB in the elbow after the turbo though. You definitely want it before the cat, as close to the header as possible without it getting too hot. From asking around it's very common to place it in the downpipe right after it bends under the firewall (that's where mine was on my N/A setup and where it is on my turbo setup).

As for replacing the stock sensor or adding another... depends entirely on how you're setting up and tuning the car. Some setups require both, some require only the wideband, and others can use the wideband to supply a stock NB signal to the ECU. For your purposes you may replace the stock NB sensor with the WB and program one of the LC-1's (or whatever WB you go with, as long as it has programmable outputs or a NB output) to supply a NB signal to one of the two analog outputs and the other will supply a WB signal to the gauge.

[supra shaun]

Originally Posted by cre

If you're just installing it along side your existing system (not intent on wiring it in to replace the narrow band) then all you need to do it run the wires to where they need to be and connect power and ground. You will need to have another bung for the sensor to screw into welded into the exhaust down pipe.



Not by itself. The wide band is a diagnostic tool; the same as the narrow band. Some systems (such as the stock ECU (TCCS), certain piggybacks and all stand alone EMS's) use the data received from an oxygen sensor to monitor exhaust gasses and adjust fueling and other related functions in order to maintain a specific threshold.

The main difference between a wide band and narrow band oxygen sensor is that a narrowband sensor is really only able to read a very small area. It reads for Lambda or stoichiometric: an optimal burn. With gasoline this represents 14.7 parts of air to every 1 part of gasoline. The problem with narrow band sensors is that as you get away from Lambda the sensor isn't capable of reading anything other than "rich" or "lean". A narrow band sensor is more of a switch; rich, optimal, lean.... that's all. The ECU adjusts fueling to keep this stoichiometric mixture by adding and removing fuel as the narrow band's signal bounces back and forth from rich to lean very rapidly (That's also why AFR gauges don't serve any purpose with a narrow band sensor).

A wide band can read a great deal of the spectrum and report conditions outside of Lambda with a great deal of accuracy; Unfortunately, the sensors are more expensive, delicate and require more hardware to control and calibrate.

Here is a *decent* article on oxygen sensors on Wikipedia.



Whenever you're asking for help with something post any error codes you may have (whether you think they're related or not). What is the error code you've received?

Oxygen Sensor Testing:
http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=119
You DO need an analog meter to test it.



Sure thing.

Do me a favor, please; work on your capitalization, punctuation and grammar... it makes it easier for me to help you if I don't have to reread posts.

if im not mistaken the 87 7mgte doesnt use an o2 sensor

[supra shaun]

Originally Posted by supra shaun

if im not mistaken the 87 7mgte doesnt use an o2 sensor

so an o2 setup would be seprate and for monitoring purposes only

[supra shaun]

Originally Posted by supra shaun

so an o2 setup would be seprate and for monitoring purposes only

toyota o2 reference is only used by the ecu when up to temp and holding a consistant rpm, when the car is starting , cold , accelerating or deccelerating the o2 goes into an open loop and the ecu ignore's o2 reference.

[cre]

Originally Posted by supra shaun

toyota o2 reference is only used by the ecu when up to temp and holding a consistant rpm, when the car is starting , cold , accelerating or deccelerating the o2 goes into an open loop and the ecu ignore's o2 reference.

Again no, that's not entirely accurate... and are you just posting as a means of thinking out loud? The ECU references the O2 sensor the majority of the time once warmed up, including when accelerating (at up to about 70% throttle). When decelerating (coasting down; off throttle and while the RPM are above the fuel cut level) the O2 sensor isn't referenced as the fuel supply is cut altogether. When decelerating below the fuel cut level or at light throttle the O2 sensor is referenced.... and so on and so on and so on... There are a LOT of conditions to this.

[supra shaun]

Originally Posted by cre

Again no, that's not entirely accurate... and are you just posting as a means of thinking out loud? The ECU references the O2 sensor the majority of the time once warmed up, including when accelerating (at up to about 70% throttle). When decelerating (coasting down; off throttle and while the RPM are above the fuel cut level) the O2 sensor isn't referenced as the fuel supply is cut altogether. When decelerating below the fuel cut level or at light throttle the O2 sensor is referenced.... and so on and so on and so on... There are a LOT of conditions to this.

well i disagree according to toyota thats not true heres a link on toyota input senor tech info http://www.autoshop101.com/forms/h24.pdf page 25 will explain how the o2 is used. my understanding is that the o2 is only used to keep egt's down while cruising and idleing, and in my opion a larger exhausts is a much better and more cost efficient way to control egt's


7mgte 475 to the rear wheels with no o2 at all unplugged and still running factory ecu and injectors and no e-manage either

[cre]

Originally Posted by supra shaun

well i disagree according to toyota thats not true heres a link on toyota input senor tech info http://www.autoshop101.com/forms/h24.pdf page 25 will explain how the o2 is used. my understanding is that the o2 is only used to keep egt's down while cruising and idleing, and in my opion a larger exhausts is a much better and more cost efficient way to control egt's

First off that article doesn't cover all the specifics for all the cars, just some of the major point... go figure, it's just a textbook. There's a group of engineers on SupraMania who've reverse engineered the complete TCCS... go talk to them about it, it's dizzying.

The O2 sensor isn't employed to reduce exhaust temps... it actually INCREASES them by leaning out the fuel mixture. Disconnect it and you'll be running in the 13's or richer and richer = cooler. EGR is employed to bring down cylinder temps.

Originally Posted by supra shaun

7mgte 475 to the rear wheels with no o2 at all unplugged and still running factory ecu and injectors and no e-manage either

Not buying it. You know jack shit about cars, probably haven't done any work on yours and have no idea what the people you paid to work on it did to it. The stock injectors can't supply enough fuel for the amount of air required for that kind of power, the ECU is programmed to cut fuel complete if a certain air flow is exceeded (keep reading I'm sure you'll get to this chapter soon enough and you can modify your story as needed then). Go back to whatever Mazda or Honda forum you usually troll on, your presence here is neither required nor desired.

God, all this jack assery has actually made me dizzy. Claims these cars don't even use an O2 sensor, then is suddenly an expert on how and when they do, what they're used for (which is also wrong) and he built a dragster out of his without making any mods?????

[btwilson86]

Originally Posted by supra shaun

if im not mistaken the 87 7mgte doesnt use an o2 sensor

You are mistaken.