wideband logging

[steveo]

playing with an innovative MTX-L (which is the gauge-based wideband), using the ol' ac pressure sensor input trick for logging.

im using 0.05896N+7.35 for conversion, which i calculated myself, then found forum posts from other people that had used the same conversion (just to confirm i wasnt out to lunch.)

i'm getting weird results:

open air (5v) which is maximum reads 22.39 on the gauge AND my datalogger (correct)
the datalogger reads 7.35 afr if i unplug the lead, which is also correct
but anywhere in the middle, 11.1:1, 16:1, the datalogger is approx +1 over the gauge reading.

im pretty sure my connections are OK, i use a ground that's common with ECM ground...

anyone ever run into anything like this?

[steveo]

mm i just noticed in the manual that this thing can be programmed with a curve just for analog output

im going to get that config software up and check to see if it's still set to factory defaults or whatever. maybe it isn't.

[steveo]

nope that wasnt it..

[EagleMark]

Someone else had that issue with the MTX-L and had to change to 0 = 10 AFR and 5 = 20 AFR.
http://www.gearhead-efi.com/Fuel-Inj...ll=1#post13725

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Conversions for 256 bit 0 to 5 volts!

For the LC-1 WideBand 0V = 7.35 AFR and 5V = 22.39 AFR.
AFR of 7.35 to 22.39 is a difference of 15.04 divided by 256 = 0.05875

Conversion for this would be:
(X * 0.05875) + 7.350000
Adding the offset makes 0 volts 7.35 AFR

For other Wide Band controllers that have 0V = 10.00 AFR and 5V = 20.00 AFR.
AFR of 10.00 to 20.00 is a difference of 10.00 divided by 256 = 0.0390625

Conversion for this would be:
(X * 0.0390625) + 10.00000
Adding the offset makes 0 volts 10.00 AFR

[steveo]

thanks thats just what i was looking for! i'll do it up right now and see how it goes.

i just hate how every damn time you unplug this thing it assumes free air calib, so every time i want to take it out and bring it in where i have a serial port, i have to purge my exhaust or pull the o2 out

i figured a good trick for open air calib, though, since this wideband is in a really hard spot to access now... just hook a vacuum cleaner up to the exhaust and disable the injectors while cranking for a bit. purges the living hell out of it for open air calib. in a short amount of time, the calibration reads just like it did in totally free air.

[EagleMark]

I have a Serial to USB adapter to hook up to the Innovate...

[1BadAction]

i figured a good trick for open air calib, though, since this wideband is in a really hard spot to access now... just hook a vacuum cleaner up to the exhaust and disable the injectors while cranking for a bit. purges the living hell out of it for open air calib. in a short amount of time, the calibration reads just like it did in totally free air.

That is a freakin awesome trick. I like it.

[EagleMark]

i figured a good trick for open air calib, though, since this wideband is in a really hard spot to access now... just hook a vacuum cleaner up to the exhaust and disable the injectors while cranking for a bit. purges the living hell out of it for open air calib. in a short amount of time, the calibration reads just like it did in totally free air.

Using a vacuum cleaner really sucks...