LC1 AFR not logging correctly

desiromeo812 · Apr 29, 2012, 06:45 PM

Hello all,

Im trying to log my AFR.. it doesn't let me review it right in the log viewer in evoscan. I tried using 2.7 and 2.8. I have Lc1 tapped into rear O2. Using formula that comes with evoscan..... Priority 1, response bits 2.

Attached is a pic of how it looks.

thank you guys.

richardjh · Apr 30, 2012, 02:27 AM

That looks right to me... Looks just like mine, anyway...

What do you think is incorrect?

Rich

desiromeo812 · Apr 30, 2012, 05:13 AM

Oh I was under the impression the line should b smooth like the rest of them, instead of being a constant zigzag.

richardjh · Apr 30, 2012, 05:48 AM

It's just the analogue voltage jiggling a bit. If I feed in a constant voltage, eg. 1.0 volts fixed, the ADC sees it jiggling up and down by +/- 0.1V.

On mine, I've got it interpreting 0V as 10:1 and 5V as 15:1... which means it's accurate to around 0.1 AFR - certainly good enough for me to tune to!

But accuracy would start to become a real issue if you wanted 9:1 <-> 18:1 range. That 0.1V jiggle would really start to hurt for a wider range.

Hope this helps!

Rich

PS. I'm not actually feeding in analogue to the rear-o2. Instead, I've patched into pin 8 of the OP2.0 itself. Seeing as our graphs look so alike, it's quite possible the jiggle is right back at the LC-1 analogue source, rather than an issue at the ADC (ECU, OP2.0). I'm sure we've both got our respective groundings and wiring good.