MPGuino injector signal negative or positive?
 

I just hooked up my MPGuino to a 91 Civic Si and it doesn't read anything :(
My ECU pinout chart reads A1=injector 1 A3=injector 2 A2=ground to relay /wA4 and A4=ground to relay /wA2 I read on the guino wiki that you hook to the injector low/common/ground, this means negative right?

Would it work if you hook to the positive signal ie A1? Am I likely going to have to run a wire into the negative at the actual injector?

My VSS didn't work either, but I'll deal with that next.

Got a link to a schematic or a way to post the picture you are looking at?

Also can you rig up a bench test (switch the injector lead on and off while plugged into the usb port)?

Thanks for the tips. On my cell atm so will post diagram later. I hooked up to the A1 pinout and it now reads GPH. It froze a couple times though. Will takd the gauges out later and test the speed pulser and if it works will run a wire from there. Hope I dont need to buy and swap in a electric sensor, maybe the manual lies. I wonder if there is a way to make a knob with 5mph markings to send a signal for cruising calculations.

Apparantly the web page, workshop manual, and online diagram were not correct for my car even though they all said B16 was the speed sensor wire. I tried setting the pulses per mile to 1 and it was reading 2.5 going down the road and 99999999 at idle and stopped, so obviously not the correct wire. I'll pull the gauge panel out and see if there is connections there like the factory workshop manual says. If not maybe I can rig up something or figure out a constant speed knob for cruising anyway.
Of course I have to get it back from the dead first :\

automatic shut off
 

I finally got the VSS working (factory service manual listed the wrong pinout but right color wire, something to contemplate later, not to mention the listed pulses per mile are off by more then half,) a 88-91 Civic does not need to be swapped to electronic speedo from cable. There is a VSS pulser driven by the cable. I will write a how to hoping there is anyone that cares.
Anyway, I need to calibrate still as it froze on me leaving my total distance after fixing to 10 miles.
The only issue atm is that it will not shut off. Everything reads 0 and the car is off but it just stays on. I set the timer to 42 seconds even. I have the latest code reloaded off google as I plugged back in too soon after a freeze and corrupted it.
Also, while I'm at it, what is the default vss and injector delay(I'm still looking for a good enclosure and may have bumped a number while trying to ok everything after changing vss?) And the scratchpad/odo setting is right now nothing?

you can use the default settings and calibrate from there if you don't see something close to your car in the wiki. The scratchpad is just a scratchpad, I use it to "jot" down my odometer reading when I fill up and I want to calibrate the mileage to the odometer.