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I have done some various measurements on a running vehicle. Trigger is by a 4 Volt signal (I didn't check the trigger time but the scale was set to 1 second and it was just a vertical blip) that does not change at all with RPM. I suspect it is extremely low amp, logic level signal.
How to output a logic-level ignition signal Use the same driver as the original IGBT is driven from, just solder a jumper wire in place of the IGBT (don't solder IGBT for given channels), between the gate and drain the 2 pins closest to the EC36 connector, and use ign_out=70 in your config /Emil |
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| h[2]=05 0A 05 0A 05 0A 05 0A |
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Dwell - for LS1 ignition transformers
I have measured dwell: * dwell length is around 59 degrees at all engine speeds and loads. * Duty cycle was at about 95%, stayed constant. Please correct the above, obviously there must be some misunderstanding as 59 degrees is not equal to 95%*120 crankdegrees. * I probably screwed it up. I stuck my Snap On Vantage (an overpriced but extremely nice multimeter/scope. I think more like a graphing multimeter) A) wires on the trigger and the other on ground, ran the truck (v8) and changed between the different scales (dwell, duty, pulse width, voltage), I assume that is the wrong way todo it? There really are many ways, eg.: * scope * soundcard * DVM in DC voltage mode (20V): duty = measured_voltage / (VBatt - 2.5V). Knowing RPM and duty, you can calculate dwell ** DVM + on VBatt ** (min.600V) diode (eg. ES2J or 1n4007 in GenBoard/VerThree/RescueKit ) used for the same purpose as on TimingLight *** cathode on ignition channel (ECM output that goes to primary) *** diode anode connected to DVM - ** optionally 270 .. 1000 Ohm parallel with the DVM. A LED in series with 270 Ohm is the best, basically same as on TimingLight (except that lower brightness is used for indication than for a real timing-light). -* Pulse width changed dramatically but if I understand it correctly: if either of the above (59 degrees or constant 95%) is true, that is natural consequence of engine speed ( pulse period decreasing as RPM increases) I never mentioned coil near plug, I said LS1 thinking that was a good description and I keep forgetting that this is world wide and most of the world has little interest in north american V8 |
| Trigger - for LS1 ignition transformers |
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I have measured the trigger signal: (originally measured it as dwell but now realize that I can't measure dwell, it is not accessible.
* Trigger signal is a constant 4 volt, logic level signal. * Trigger time varies. ** Start/Idle 1 ms ** 3000 rpm approx 4 ms ** Full throttle/5500 rpm .55 ms ---- How to output a logic-level ignition signal Use the same driver as the original IGBT is driven from, just solder a jumper wire in place of the IGBT (don't solder IGBT for given channels), between the gate and drain the 2 pins closest to the EC36 connector, and use ign_out=70 in your config /Emil ---- I connected a coil just to see if all works. While my 2 year old turned my "engine" over (drill on a modified distributer) I would change the dwell in MegaTune while measuring the voltage at the trigger signal with a scope. The voltage "on" time is basically exactly half of what I set it to in MegaTune. Is this normal?? I expected them to be the same. I assume there is no simple way to vary the trigger "on" time with RPM so I played with the various settings. To get 5.5 ms I set dwell to 11, very violent spark, don't expect the coils or plugs to last that long at that setting. Set it to 1 ms (2 in megatune) and the spark is ok, will jump a gap of about 1/2 inch, didnt push it any further for fear of arcing to the ecu. Set it to 3 ms and the spark "looks" about right. |