I'm coming at this from the DSMLink perspective; over there, we have the ability to reuse stock sensors that we no longer need as loggable inputs. One of the most popular is to log boost, which we can already do with the JDM MAP sensor.

One of the other most popular uses is to log a wideband. Since some of us no longer need our rear O2 sensors for anything, that's an obvious place for a narrowband input. However, with DSMLink, we can run a 5V input into it.

So, the astute already know where I'm going with this: would there be any problem running a 5V sensor into the rear O2 ECU input? That would give us the ability to directly connect a wideband (or other 5V sensor) for logging, without needing special support in the logging program. (Going further, if one were willing to make code changes, changing over the front sensor input to a wideband would allow for finer-grained control, and for a "direct replacement" of the O2 sensor with a wideband, no fussing around.) Calculation routines could be easily borrowed from the DSMLink source.

I have a hard time believing I'm the first to suggest this, but searching didn't turn up much; my apologies if this is a painfully obvious topic.

 

logic,

I think I brought this up years ago before the ECU disassembly was really being looked into.

I know this is a little off topic, but I just bought an Innovate SSi4. It's about $100 and it gives you 4 0-5V inputs for logging external sensors. Currently I use it to log my GM 3.3 bar map sensor. I also have their LC-1. Just thought I would throw this out there as an option for you.

Back on topic...I know this has been discussed before and I think it is doable. However, I don't think anyone has really looked into it as of yet. I know someone like tephra or Bez can implement something like this, given they have the time and incentive to do so.


Eric

 

What I'm curious about is, would you even need special code support?

In other words, if I started feeding a 5V sensor into the rear O2, would the raw rear O2 voltage logged in, say, Evoscan, see the full range of data, or would it only be able to see a 1V range? (And more importantly, would I "the the smoke out" of my ECU? ) (To be fair, I haven't looked yet to see whether the value logged is a single byte value or two-byte, and what the logged range is right now. So, while you might be able to feed the sensor input, the logged value might still flatline somewhere.)

The Innovate multi-input stuff is slick, no question about it. But for a lot of applications, where all you'd want to do is add a single external sensor to the mix, it's not really worth the investment. Worst case, I can wire in the narrowband output of the wideband to the rear O2 and add a new calculated value to Evoscan, but I'm curious if the ECU will do anything useful, out of the box, with a 5V source.

(Steering offtopic even more, are you using LogWorks for gathering ECU logs as well as the SSI-4/LC-1 output? If so, how has that worked out for you? Any problems adding new/weird interpreted values? Probably good fodder for a separate thread, but anyway. )

 

Yes, I use LogWorks. As I mentioned before, it is the logger most similar to DSMLink (realtime graphing, etc), and since I came from DSMLink, like you have, it was the easiest and best logger (in my opinion) that was available.

With LogWorks, I have been logging AFR from their LC-1 and boost from my GM 3.3 bar (hooked to the SSi-4) for a while now (along with any other ECU channels) without any problems. It's great to have wideband and boost in the same graph as all other MUT values, like RPM, etc. And with the SSi-4, I have 3 more 0-5V available inputs, so I can add temp sensors, pressure sensors, etc for future tuning.

Anyway, back on topic. I don't know the answers to your questions. Hopefully someone can chime in and help you out.


Eric

 

One more obvious point...

Since you basically live right next to me, you can't do this until the readiness bits are found for the obd-II test for the cat efficiency. If you disable the rear O2 sensor/heater in the ECU, then the cat efficiency test will not run and you will fail emissions in Illinois.

So, that is another part of the equation that needs to be solved before using the rear O2 as a loggable input.


Eric

 

Heh. That, I'm very familiar with (it's the reason my 2g has DSMLink instead of an EMS). Luckily, that's would be a relatively simple thing to swap back at emissions time, if needed.

I know the readiness tests are still an issue (although the first part is basically done: resistor on the heater circuit, periphery change for the sensor check), so this isn't quite a ready-for-prime-time idea just yet, unless you live in Florida. Just something to get people thinking, more than anything.

 

I am probably incorrect, but I thought what we were doing with the ECU peripehery wasnt disabling the heater circuit but rather just disabling the CEL? I can still log voltage from my rear O2 with the periphery set to 56d8, I just dont get a CEL.


Or am I wrong?

 

I'm pretty sure the periphery disabled the heater and the rear O2 checks. So, the readiness tests wouldn't run, resulting in a failed OBD-II emissions test.


Eric

 

That would explain why it logs voltage but it is WAY OFF if the heater circuit is not on.

 

Do you know which ECU pin is the rear O2 on the IX? The wiring diagram I have only shows one O2 sensor and I dont know if it is for the front or rear

 

the FAA thing just disables the O2 routines partially.

You should be free to use the rear 02 input for whatever you want

just make sure you get the volts etc correct

 

im going to try and hook my aem up like so

power to pin 25
gound pin 92
white analogo to 81

this way the rear 02 reading is a true lambda wide band voltage

 

bump.. anyone know which pin is the rear O2 on a IX?

 

did it work?

 

nope im gonna try the other wire for analog out put, the rom might need editting