Narrow Band O2 Sensors w/ E85

[Asteroid]

Is there any way to use the OEM narrow band O2 sensors for short term fuel trims with E85? I'm converting to E85 on my NA 442 LS engine with a SD tune. Do I just disable the stft's? I suspect they would confuse fueling with the afr so far from their normal operating range.

Asteroid

[Iam Broke]

All the 02's know is stoich regardless of fuel. They are really lambda sensors.

I run mine with LTFT's disabled & STFT's enabled. Positive LTFT's skew WOT fueling so I prefer to avoid this.

Stoich at cruise is still 1.0 lambda regardless of fuel and my wideband reads 1.00 lambda at cruise on any fuel with the narrowband 02's doing the control.

If you are going to run different fuels it makes sense to get away from AFR and think in Lambda.

After the open loop VE & MAF are dialed in, I use the narrowband 02's to trim the last few % STFT's in closed loop and nail it in. YMMV.

Bottom line is the stock narrowband 02's switch fine on E85.

[Asteroid]

Thanks, that is good news. I also run with stft enabled and ltft disabled. I will continue to run that way on E85.

As to 'lambda', I have no problem thinking in lambda. Is there any way to get the pcm to think in lambda?

I had an LM1 but it got submerged in water and no longer works. It was awkward anyway so rather than replace it I bought an E85 gauge kit which includes the WB sensor and an analog output. I plan to log lambda data on my scanner from this unit. I understand that I need to create a PID to make this happen, something I have not done before. I have not received the guage kit yet so I do not know if it will display lambda. I know it will display afr in the E85 range. I don't really care if it displays afr or lambda, I just want to tune in lambda.

I suppose I could log afr on my scanner without doing the PID mod, but then I would not be tuning in lambda and it would be reading in 'gas' values, not E85 values, correct? This sounds like a PITA.

[Iam Broke]

we'll have to see what your WB will do. I have an Autometer pillar mount gauge that outputs 0-4v scalable and the display is switchable between Lambda and AFR. I have the meter output scaled from .8 to 1.2 lambda linear 0-4v and bring it into the ECU through the unused (on mine) EGR position input.

There are a few recent threads on logging lambda error, search for those, it might help your WB setup. % error is % error whether AFR or Lambda.

[Asteroid]

I have the EIO feature on my HPT cable and I have been logging WB data from an LM1 with no problem (running on gas). I plan to continue WB data acquisition this way with E85 so no need to bring it in through the EGR. My new E85 guage will output a lambda signal from 0-5V (afr 5.7 - 11.9 on my guage display).

I understand the scanner will display this data on the 'gas' scale (14.7 stoich) unless I change this in some way (PID?). I have no experience with customized data (PID) so with that said, I have some questions:

If all WB sensors work in lambda, there must be some agreed upon voltage that is always stoich (lambda = 1). What is that voltage? Mid scale, 2.5v? or what?

The reason I ask this is because I want to know where the scanner gets its value for stoich AFR? If it gets it from the PCM by way of HPT input for stoich for the fuel used. Then if I have flashed stoich = 9.7 in my .bin file, why would the scanner not display AFR around that point? If the scanner does not use the flashed value, then it must be using an arbitrary 14.7 or something which leads to errors depending on what fuel is used.

The way I see it, the WB delivers a lambda signal (0 to 5v) regardless of fuel used. The scanner takes this data and converts it to afr. In order to do this it must start from some point that it thinks is stoich afr for the fuel used (v = 2.5?). If it gets this value from the PCM then why would there be any need to modify the display with a PID?

I'm talking in 'afr' at this point because I have to walk before I run. I can go to lambda after I understand the processes involved.

[nicul15]

As i understand the 14.7 might not be real. it is just stoich unless you work the sensor input formula for your specified fuel. the focus should be on the delta during PE. that is where the lambda comes in.

I just started so I might be wrong. Also when calibrating your WB with the innovative software you select the stoich of which fuel you are using.