- Sun Mar 02, 2025 3:46 pm
#71050
Hi guys. I need some help.
I have basic distributor with VR - pickup coil connected to VR conditioner on speeduino.
I was doing some tests on a scope and watching ignition coil and trigger signals. As I understand, speeduino needs two trigger inputs to calculate time distance between triggers > to calculate rpm and than it starts outputting ignition.
But when triggering stops (when engine stops/stall - carburator problems), speeduino is still ending with outputting 4 to 6 time SYMETRIC additional sparks. This is not a noise - i would see it on my scope and also my VR cable is shielded and grounded at the ECU side. And i am hearing it under my distributor POP-ping everywhere, especially when distributor rotor stops between two contacts for spark plug leads. And I am afraid, that it can damage my VR pickup coil or even go further to my speeduino VR conditioner.
I know that under normal operation, the ignition key turns off coil and speeduino. But when doing bench testing and engine stalls, I think this is not really a safe thing for distributor internals, windings and also ignition coil can get damaged firing 6 sparks just on random place, which in some cases unfortunately it's not a particular spark plug. If ignition coil has nowhere to spark, it can damage itself - it can broke through insulation.
So why speeduino still makes 4 to 6 additional sparks after triggering stops? What is the purpose of this? I think that the normal behaviour should be, when there is no logical trigger pulse in expected time frame, also no spark should be made.
I have basic distributor with VR - pickup coil connected to VR conditioner on speeduino.
I was doing some tests on a scope and watching ignition coil and trigger signals. As I understand, speeduino needs two trigger inputs to calculate time distance between triggers > to calculate rpm and than it starts outputting ignition.
But when triggering stops (when engine stops/stall - carburator problems), speeduino is still ending with outputting 4 to 6 time SYMETRIC additional sparks. This is not a noise - i would see it on my scope and also my VR cable is shielded and grounded at the ECU side. And i am hearing it under my distributor POP-ping everywhere, especially when distributor rotor stops between two contacts for spark plug leads. And I am afraid, that it can damage my VR pickup coil or even go further to my speeduino VR conditioner.
I know that under normal operation, the ignition key turns off coil and speeduino. But when doing bench testing and engine stalls, I think this is not really a safe thing for distributor internals, windings and also ignition coil can get damaged firing 6 sparks just on random place, which in some cases unfortunately it's not a particular spark plug. If ignition coil has nowhere to spark, it can damage itself - it can broke through insulation.
So why speeduino still makes 4 to 6 additional sparks after triggering stops? What is the purpose of this? I think that the normal behaviour should be, when there is no logical trigger pulse in expected time frame, also no spark should be made.
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