diy mpg gauge

[itjstagame]

Sweet updates! Well I still haven't tested stuff because I don't have stereo line input . But now I'm mostly driving the Festy anyway, the Truck has gone <50 miles in 1 month. But I would like to get it tested and then install on the Festy too.

I can't believe it took be over a year to do becasue it's pretty cool.

As for my 'bumpy' pictures. I really have no idea. I'm quite confident that the larger spikes are the events I want. It's certainly possible the noise could be ignition. It seems to increase with throttle and my unshielded 12 gauge (can't recall actual gauge but not too thick) wire goes right over almost all the ignition wires and the distributor. I mean it's at least 3" away all the time, but still...

As for my confusing post, the VSS is usually a magnet pulsing a coil as the driveshaft or something in the tranny spins, so it produces a AC. Yes I assumed the peak, actual voltage generated would stay about the same, so more AC means higher duty cycle/more AC pulses. Either way it's looking ok when I recorded it, but I used a 33k resitor which may have been a bit too high.

And yes, on a 4 cyl you'd have 2 injections / crank rotation, 4 / cam rotation. On a V8 this is obviously different, but mine is even more different because it's TBI and only has 2 injectors right at the start of the intake runner that feeds all 8 cylinders.

I had originally assumed 2 batch fires / cam rotation (full OTTO cycle), but after reading online it is actually supposed to inject 8 times, I at first thoght this meant 4 times each / cam rotation, but that still looked awefully low, so I decided each one must be firing 8 times, so that's 4 times each / crank rotation. But yeah, definately with it just idling I can see really strange suff, like I can tune so that idle is about 1000 rpm but then when it warms up it can be as low as 350rpm. I'm sure it's just not calculated right, but sometimes I really think it's firing less times/cycle under certain conditions.