[Andy198712]

Hello, long time viewer, first time poster!

I have a NO2C I've built to data log and or view what's happening on my carb'd KTM 950 SM (75* Vtwin)
I have a Wideband fitted ( PLX)

made up a wiring harness, just a basic one for now, using extra connectors to match the factory ones I've made a piggy back harness of the TPS signal, this works and I've calibrated this.
I can use the 0-5v output from the PLX to give me an O2 reading (couldn't start the bike as it was getting late but seems to work)
The MAP sensor works but I haven't connected it to vac lines yet but will.
I'm not concerned with temps yet.

Where I'm stuck is RPM signal.

I have the PSIQ DSC on the board, no jumpers yet.

I read somewhere that piggy backing a VR sensor doesn't always end well??

so I have ran a wire from the KTM ECU tacho output (my bike doesn't have a tacho but the space is there on the plug and it "can" run a tacho) and I'm put that into Prim+

But what settings do I need to choose? Basic Distributor? and not the 24-2 wheel the bike uses?
and which jumpers would I jump?

I'll double check this but with the ignition on the pin seemed to be 10.9V without running but will check this and see how it changes with RPM


OR

Do I just scrap this idea and add in a piggy back connector off the stock VR sensor and hope it doesn't mind sharing a signal with the stock ECU?


Thanks
Andy

[PSIG]

I would first run it off the Tach output. If it's 5V signal, then direct to the input, and set for distributor. Alternatively, an injector output. The issue with sharing a VR is that low-impedance conditioners (such as the DSC) can alter the VR signal, which is already weak at low speeds such as cranking. Not a problem otherwise, and unique to this configuration.

If you are stuck sharing the signal, then I would use a high-impedance VR conditioner such as the MiniMAX A2 or similar that should not alter the signal.

[Andy198712]

Thanks,
I’ll have a look while it running and see if my multimeter can see what it’s doing.
Hopefully 5v!
If it’s 12v I’ll have to get a different vr conditioner and share the crank signal I guess


What jumper settings do I do for distributor? I have no jumpers at the minute fitted. Couldn’t work it out from the wiki as it’s not a VR or hall I guess

[Andy198712]

My thought process was that if I jumper it as if it was VR that would be the safest place to start as it’s covered for higher voltages.
Where as if I jumper it as hall it’s especting only 5v

But distributor should be 12v output right?

[PSIG]

I understood it was an ECM output? Check the signal voltage. 5V OK. 12V OK with conditioner. Coil(-) not OK (high voltage flyback 150 to 400+V). You will need a special circuit for coil(-) signal source.

[Andy198712]

I understood it was an ECM output? Check the signal voltage. 5V OK. 12V OK with conditioner. Coil(-) not OK (high voltage flyback 150 to 400+V). You will need a special circuit for coil(-) signal source.

Sorry I probably explained it wrong.

The stock ECM’s tacho output pin.

Wired into my NO2C Prim+ pin

I’ll set it to distributor in the settings, what do I do with the jumpers?

Very helpful thank you!
And I keep the trigger settings the same for the DSC “falling edge” yeah?

[PSIG]

I don't know the signal form, so I would try jumpers each way. It shouldn't matter Rising or Falling for a general reference signal like this, but again I'd try both for best results. I will often list the combinations to try them all without confusing myself:

• Pullup on, Falling
• Pullup off, Falling
• Pullup on, Rising
• and so on with every possible combination, adding pulldown and other untried options.

[Andy198712]

Okay so no joy this time

Tried:
TSC and DIRECT both raising and falling with no other jumpers

TSC with jp4 on, falling and raising

Direct with jp4 falling and raising

Nothing on any sadly. I do get an orange light on the condition on the 1 with TSC with jp4 on though, perminantly.


I guess next is try the VR sensor piggy back idea and see if that works, if not or fails at revs then get a different conditioner
Hard to find the minimax A2 In the U.K. it seems!

[Andy198712]

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[PSIG]

Can you get a direct signal from the sensor with an oscilloscope? While trying different methods to condition it usually works (if everything is OK), it is much easier if you can "see" the signal (voltage and wave form), and then how we can handle it.

While signal conversion is frustrating at times, it is amazing how well it works with literally hundreds of different signal profiles we see. The factory only has to condition one signal profile. Theirs. Hang in there!