stupid question about widebands

[bobcratchet555]

hi all,


every wideband that i see for sale comes with some "box" to convert the wideband's output to a 0-5V signal, and provides calibrations for what those voltages mean in terms of a/f.

my question is: what voltage does the wideband itself put out? is it in the same range as the typical narrow band? are calibrations available for the raw output of these sensors?

reason i ask is, i'd love to use the rear o2 sensor ports on my ecu for logging purposes. i understand that the ecu will not be able to react to this information without tuning, but it'd certainly be cheaper to just buy the sensor and log the voltages that way, no? rather than buying the "box" to covert to 5V output, then trying to figure out a way to include that data in my logs

has anyone ever tried this or am i completely off base?

[steveo]

here's the equation, assuming you can drive the wideband pump in a stable fashion, should be a cakewalk, right?

just buy the controller. there's no shortcut unless you're an extreme electronics hobbyist.

[bobcratchet555]

here's the equation, assuming you can drive the wideband pump in a stable fashion, should be a cakewalk, right?

just buy the controller. there's no shortcut unless you're an extreme electronics hobbyist.

wideband pump refers to what? the internal heater? sorry, i'm a bit of a n00b here, which is probably why i'm confused as to why no one does this. The wideband outputs a voltage (in the range of ??). The ECU reads a voltage (in the range of 0V-1V). My thought process is that i can use the ECU to log the voltage, and then apply the calibration to understand what the result is.

i dont have a problem buying the controller, but then i have to most likely buy additional stuff to log the data, which just seems counter-intuitive.

i have found a schematic to breadboard a relatively cheap op-amp setup to take the 5V output of the wideband controller and scale it to 0V-1V which the ECU could then read. But definitely adds complexity and cost.

[bobcratchet555]

steve-o, thanks for the input. sorry if my posts sounds frustrated :)

maybe i should float these questions instead:

-how are you all logging your widebands?
-what wideband/controller combos is everyone using?

i did see that the innovate wideband allows you to program the output curve:
https://www.innovatemotorsports.com/support/manual/LC-2_Manual.pdf

maybe i should look into something like that if i wish to log the output using my existing ECU's rear o2 sensor monitors

[steveo]

wideband pump refers to what? the internal heater? sorry, i'm a bit of a n00b here, which is probably why i'm confused as to why no one does this. The wideband outputs a voltage (in the range of ??). The ECU reads a voltage (in the range of 0V-1V).

it's way more complicated than that. the controller must produce a varying drive current or its band is very narrow. it's not just running a simple heater, it requires control logic both in and out. it takes a lot of screwing around to get it right so again, it's one of those things that unless you have to do it just because you need to know you can, it's not going to save you any trouble.

here's a description i googled for you


Wideband oxygen sensors actually make use of a narrowband sensor, but with some additions. Specifically there is a control input on the sensor that allows the stoich point to the shifted rich or lean, based on how much current is injected into that control input. This means that with a specific amount of control, the sensor can behave like a 13.5:1 stoich sensor for example. So the output would be 0.45 Volts at 13.5 AFR. Or it can be made to be leaner than 14.7:1 AFR. The changeable range is about -50% to +50% for a common Bosch wideband O2 sensor.

Now, a wideband sensor HAS the ability to detect and measure air-fuel ratios other than 14.7, but it requires a varying control to do so. This is the job of a wideband controller. It dynamically and VERY rapidly adjusts the amount of current to the sensor control input to get an output of 0.45 Volts. At that point, the controller knows what AFR ratio is stoichiometric for the amount of current injected into the control input, and can calculate the air-to-fuel ratio from that. This is typically puts out as a varying analog voltage for a gauge or ECU.

And there it is... without a controller, the wideband sensor is not very useful. The controller also performs other important functions such as heating the sensor, so it gets to it's operational temperature much quicker (compared to waiting for it to heat up due to exhaust gas alone). OEM ECUs typically have a controller built in, but aftermarket ECUs usually have these as standalone boxes.


-how are you all logging your widebands?
-what wideband/controller combos is everyone using?

anything with a programmable 5v output should work for you, a programmable output curve would be handy

a common practice is to find an unused 5v input on your ECM that is in the datastream (ac pressure sensor is a common one) and just log from there but you can suffer from a lack of linearity on those inputs

if you're doing fine tuning i've found setting a fairly narrow AFR range increases the accuracy in the log (11:1 to 15:1 or something like that)

[ralmo94]

steve-o, thanks for the input. sorry if my posts sounds frustrated :)

maybe i should float these questions instead:

-how are you all logging your widebands?
-what wideband/controller combos is everyone using?

i did see that the innovate wideband allows you to program the output curve:
https://www.innovatemotorsports.com/support/manual/LC-2_Manual.pdf

maybe i should look into something like that if i wish to log the output using my existing ECU's rear o2 sensor monitors

To answer your question, I log WB with EGR voltage.
You still need the controller. The gauge/controller, sends out an analog 5v signal.
Some people log it on the AC pressure circuit. I don't like EGR, but I do Like AC, so
I delete Egr and log AFR on EGR circuit

[bobcratchet555]

it's way more complicated than that. the controller must produce a varying drive current or its band is very narrow. it's not just running a simple heater, it requires control logic both in and out. it takes a lot of screwing around to get it right so again, it's one of those things that unless you have to do it just because you need to know you can, it's not going to save you any trouble.

here's a description i googled for you





anything with a programmable 5v output should work for you, a programmable output curve would be handy

a common practice is to find an unused 5v input on your ECM that is in the datastream (ac pressure sensor is a common one) and just log from there but you can suffer from a lack of linearity on those inputs

if you're doing fine tuning i've found setting a fairly narrow AFR range increases the accuracy in the log (11:1 to 15:1 or something like that)

Thanks. Now I understand why the controller is necessary.

Previously i had been "googling" for calibrations, rather than trying to understand how the sensor itself works. Clearly i should've started with step 1 before moving on to step 2.

Based on some of the commentary here, i think the innovate LC2 with the adjustable output would be a good fit for me. it could simultaneously emulate a narrowband sensor while still logging wideband. fun.

[steveo]

i had an lc2 for a while
its good
the fake narrowband outputs are good enough to use when you're temporarily tuning with only one o2 hole but its best to use a real nb o2 for closed loop, most people find the simulated signal eventually throws a code or doesn't run quite right