[nickdigger]

I finally plugged my guino into the civic today, and fired up the engine, and got GPH of 0.2 or so, watched it climb to 0.5 when i stepped on the gas, & fall back again.

Then, i shut off the engine, and GPH jumped to 8.15, and RPM of "240" (translates to 700 "real" rpm, i figure). It normally did this on the bench (before i installed the pullups & diodes), but I chalked it up to "ambient static" since it wasn't wired & grounded, and the numbers seemed to change if i touched it.

Now, i've unplugged the vss & inj inputs, and when it's powered on, i'm reading pulses of 1.6v at the inj lead, and 0.8v at vss. Apparently 0.8v isn't high enough to trigger VSS interrupts, but the injector sensor is going to town.

I'm using a Seeeduino 168 board, with 5.1v zeners and 100k pullups on each input. Before installing, I measured the resistors & both zeners had 0.7v forward voltage.

Does anyone know (a) what might be causing these self-generating signals, or (b) if the sensitivity can be changed in software to ignore them?

I'll add that when i was feeding it with an arduino signal generator, it would crash when using 300ohm resistors, but ran fine with 100k.

Without pullups & diodes, and without a sig-gen, my ambient readings were steady at 52.5 MPH and 5.56 GPH. Now, with pullups & diodes, and no sig-gen, i get 0.00 MPH and 8.15 GPH.

Working back from 8.15, i figure the fake pulses are 'On" about 0.34 sec out of the 1/2 sec loop. And saying that out loud, I recall rmccomiskie's "too-long-pulse" hack, and figure I should add the code.

Also, just playing with it some more, GPH follows this sequence when i change the LCD brightness: 8.15, 0.00, 0.7, 8.15, and stays at 8.15...
A minute ago, it behaved the same no matter what brightness i had (0-3), but now, brightness==0 has GPH at 0.00, and now brightness 1 has GPH fluttering around at 0.00, 0.7, 0.25, 0.15, 0.00. Brightness 2 & 3 have higher GPH, but are no longer steady 8.15 like before. Almost all my benchwork was at "1" so as not to blind me.