diy mpg gauge

[itjstagame]

Ok, another question in case Skewbe comes back. I recorded a run today (just fuel, no VSS yet) and looked it over. My previous test idling looked like I needed a -20 threshold or so and I think this is still good, but I wanted to ask about the strange things I'm seeing.

If you look at the attached pictures, I'd say 'bumpy' is pretty much the normal output I see, here you can see where I'm revving up and accelerating a bit after a turn. Strange that not only the pulses get stronger but I get a very high 'noise' wave. That is, are there only 3 fuel pulses in this picture? Why is it so noisy at the end?

More bumpy is at the same zoomlevel and further in the trip. Now the noise is getting sharp points. Very strange. Again would you say there's only 3 injections there? The 'noise' is starting to look more like injections. At this point I measured the low points of the noise and it was -16, so it's getting close to my threshold.

Then in the middle of my trip it went 'flat'. This is the same exact zoom level and noise is very very minimal and the injections look obvious. There's only two here now. My TBI is supposed to inject once for each cylinder (I think both injectors fire once per each cylinder or 4 times each per revolution), but here I calculated at at this rate in the 'flat' picture it's only 1100 injections per min. That can't be 300 rpm and even at double that, 650 rpm still seems too low (I have no tach in my truck). Is this some form of DFCO or something? It's injecting once per rev and skipping a bunch of cylinders or something?

Even stranger is my SoundForge chops out dead air in the middle. I had many points where it said it cut out 2-3 secs here and there. That must mean the recording was completely flat with no noise. DFCO maybe? This run was only at 45MPH max and I just left it in overdrive the whole time, so I doubt my revs would be high enough for DFCO (as I understand it).

Thoughts ?