(Image grab from my o-scope, you can see there is a bit of noise even at idle speed) I'm building a bit of custom hardware to go on my 630 SMS. After going through the wiring diagram I can't make out how tach (RPM) signal is picked up or what wire it's on. ECU and dash get it somehow, the best I can figure out is from a crank sensor, but I'm not sure. Right now I'm getting signal off a wire wrapped around the spark plug, but I'd like a cleaner way (cleaner in terms of signal quality).
It looks like there's a sensor to the right of the GPS in the wiring schematic that may read the position of the crank. It's unlabeled but I see nothing else on the schematic... I can tell you tach signal is white/red stripe at ecu
the wiring diagram shows a white/red trace on the positive side of the coil, which makes sense. If you probed the white red to get that signal the noise is most likely back EMF created by the coil. The ecu would know the revs/crank angle from the crank angle sensor. I can also see two lows and three highs in that signal - maybe the dash/ecu/whatever is reading the lows?
Service manual page F36 refers to a pick up sensor inside the stator cover so I'm pretty sure it's what I thought. White and brown wires going to it. Can't understand why they wouldn't make this clear on the electrical schematic? .
TrailTech taps into the wire or has a wire wrapped around the plug? Right now I have about 5 loops going around the plug, but I will try a better / cleaner pickup over the weekend. Thanks guys for your inputs! I was also thinking that unlabeled sensor is where its at.
the trail tech website says you can't tap into the coil positive (the white/red) wire as it is too high voltage for the unit. just letting you know, to be on the safe side
I tried wrapping it around the lead, but it read all over the place. I run it off the coil input wire with a resistor in line.
I also read somewhere that reversing the polarity on the lead that wrapped around the plug made a much better signal for the trail tech, could be worth googling and looking into.
Much cleaner signal from coil W/R wire. My dev board cannot deal with voltage this high though, I need to drop it down to under 5V to make usable.
Got the reading I was going for, with a bit of math I'm getting an OK result. Now how does TPS sensor on 630 SMS work :-|
TPS should just be a variable resistor, if it's a 3 wire, they should be 5v+, earth and signal wire. looking at the wiring diagram that looks to be it
