4 cyl sequential ignition - Spark C inverted?

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4 cyl sequential ignition - Spark C inverted?

Postby Wyrmidion » Fri Nov 10, 2017 6:18 pm

Hello, i'm having an interesting phenomenon in my megasquirt box. So i've done some testing in-car with my present setup.
it's got 4 LS2 truck coils and i've tested both going high and going low setting. funny thing is, either i get 3 firing, which i think is the going low, or i get 1 firing, on going high. measuring with a voltmeter i find that 3 outputs are low and one is high. i have no idea how this is possible, but changing setting reverses it, then i have 3 high and 1 low. ergo almost 5v on one and around 0.1 i think, on the other 3.
tried changing the transistor, didn't make a difference. outputs are wired the same using the built in transistor for the leds, and one built with parts on proto area.

it is prepared like in the manual for 4 spark outputs. since the circuit itself is supposed to be simple enough i'd just like to know what could possibly be wrong. all leds light up/blink when run in stim and in car. they are put in the right way around, so are the transistors.
will look into a datalog once i figure out how to do it, i'm still learning.

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Re: 4 cyl sequential ignition - Spark C inverted?

Postby billr » Fri Nov 10, 2017 7:10 pm

Post pictures of the mods made for the spark drivers.
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