Zeitronix

iTrader: (2)

You are missing a lot. There is more into correctly driving and reading wideband O2 sensor that a text book method. Devil is in details and there are a lot of details.
You would need a precise current sense and reference where most ECUs detect a ballpark of current of the O2 heater NB O2 sensor only to determine if heater is working or not. You also need more than one current sense to do it right. Fast temperature control is another important issue. And there is more.

Iowa999

iTrader: (1)

I'm only going to try one more time. Please - I beg you - read very carefully.

The ECU on a car that came with a narrow-band only has the ability to measure a voltage (from 0 to 1 vDC) plus the ability to turn a heater on and off. That's it. Actually, it quite easily could be worse than this, in that the ECU might only have the ability to detect whether a voltage is above or below .45 vDC, plus the ability to turn a heater on and off, but that doesn't really matter. The key point is this: the ECU on a car that came with a narrow-band does not have the ability to produce a variable and known level of current.

A true wide-band sensor must have a controller. The controller produces a variable and known current, altering this current (which drives what some call an oxygen pump) until an associated narrow-band produces .45 vDC. To be 100% clear: the controller needs to be able to read a voltage and then raise or lower a current to get the voltage to .45 vDC. And it needs to "know" how much current it is sending, since it's the level of current that indicates AFR.

To repeat: a wide-band system needs a device that can raise and lower a known level of current in response to a voltage reading. It is in no way sufficient that the system have a device that turns some current on and off in response to a voltage signal, so just drop the idea of using anything like the heater circuit on the ECU. (Yes, the way that the controller on some [if not all] wide-bands alters current is via pulse-width modulation, which is sort of like turning the current on and off, so it's sort of like the heater circuit, but the heater circuit on the ECU of a car that came with a narrow-band is no where near fast or accurate enough, and it doesn't actually keep track of what it's doing, so that isn't going to work.)

Before anything else, if you really want to keep moving towards a wide-band connected to an Evo's ECU (without using a separate controller) you need to address this issue. How are you going to alter the known current to the O2 "pump" in response to the voltage from the sensor? Until you address this hardware issue, whether you can alter the software to (a) convert a level-of-current value to one that the ECU can use to set fuel trims and/or (b) log the data is putting the cart before the horse.

And on the assumptions that the horse is back in front of the cart and that the water we have offered the horse is potable, it is up to you to hydrate said horse.

Iowa999

iTrader: (1)

Actually, there was a pseudo-wide-band being sold for a while that tried to take the 0-1 vDC signal and "flatten" the curve to give an actually reading. Many silly people with DSMs bought them, IIRC.

With that said, of course I agree that a true wide-band is the only real answer and is a necessity for tuning safely.

Iowa999

iTrader: (1)

Oops. Good point. Now there are two hardware issues to be dealt with. First, you need the controller for the sensor, as I have been harping on. Second, you need a much better heater controller than what's on the ECU of a car that came with a narrow-band, as Zeitronix has been gently and warmly pointing out (since he's nothing like the jerk that I am).

Boosted Tuning

iTrader: (12)

OP, did you even look at the data in the subaru thread about them testing the stock NARROWBAND against a WIDEBAND??

If you did, you would see that the narrowband is NOT accurate.

justastockevo

iTrader: (1)

i did. they used to call their factory wideband a narrowband, but that changed, even the guy who posted those graphs admitted it. the difference between their readings can be accounted for different location in the exhaust stream.

ok, i take it that subaru's ecu is fundamentally different from ours. it's acting faster, can check an input wire for resistance, can alternate voltage of given circuit in a predictable way, while ours is slow, inaccurate and just can't do that.

Boosted Tuning

iTrader: (12)

Every single thing you just said is INCORRECT.

The stock O2 sensor on a Suby or EVO is a NARROWBAND. I dont care what lil kids on the suby forum call it. Its a narrowband and will always be one.

And, our ECU is NOT " slow, inaccurate and just can't do that.".

HornstarBU

iTrader: (7)

Our (my base lancer ecu included) is one hell of a powerful device, that rivals stand alone systems while still leaving the car drivable for a daily car. Best....ECU....EVER....

Iowa999

iTrader: (1)

Now that my sides have stopped aching (a little)....

Wow. That's pretty scary. They're actually at 12:1, but their so-called "narrow-band" is saying that they're pegged at the floor, near 11:1. If they actually used this signal to tune, who knows how far they'd have to go before it got up off the floor, but there's a decent chance that the engine would go bye-bye before the inaccurate signal reached 12:1.

It's a wonder that there are any Scoobies with NASIOC stickers still on the road.

Note, however, that the main problem with the accuracy of the so-called "narrow-band" in that plot (which is really a form of wide-band, by my definition, since it has a current-supplied plate, etc, etc, instead of just a plain 0-1 vDC sensor) is that it's before the turbo. By the time the boost hits, the pressure around the sensor is very high and all O2 sensors read rich under those conditions. The so-called "wide-band" in that plot was after the turbo.

Either way, thanks for a hilarious ending for the thread.

justastockevo

iTrader: (1)

hilarious indeed. if there's anyone on this board who knows from fact what we can log from o2 ADC inputs, feel free to pm me. i'm still inclined to use that subaru's narrowband in my evo (ok, i know, i'm very wrong). thanks everyone.