White_FC

Hi guys
quick question.
Does the ECU pulse a 'negative' signal to the leading ignitor or 'positive' one?

I realise that it is a 'dumb' ignitor and doesn't in itself control dwell, but is the pulse negative or positive?

NZConvertible

If you can believe the little arrows on the wiring diagrams (and in this case I think you can) then it's a positive pulse from the ECU.

White_FC

Thanks NZ,
I have the ignitor right in front of me, there are a few terminals on it.
3 did have wires solderd onto them.

One has the letter 'B' next to it, presumably battery.
Another one has 'IGt', the pulse presumably.
The last one has 'C' next to it, common? ground?
Havnt looked at the FSM, probably should've done that, but ill take your word that it's positive

what you think?

HAILERS

Try this site/article: http://www.teamfc3s.org/info/articles/demystifying.html about halfway down the articel where *he* says " Notice when the 0-5 volts IgT pulse goes low, primary dwell ends and the coil fires. "

And later in the article where the trail 1 and trail 2 work ........differently.

Personaly I know nothing about ignition or electrical things. I'm a tire kicking grease monkey.

White_FC

Thanks HAILERS, that re-enforces what NZ said, that its a +ve pulse.
Only thing is my microtech puts out a 12v pulse i think?
hmm... grr.. should be ok.. if it blows up, it blows up..

Always apreciative of grease monkey input.

RETed

It should be -ve for the TRIGGER signal.
They are all pull-to-ground signals.


-Ted

White_FC

Er... non-comprende' amigo.
So the ecu switches from +5v to GROUND? not +5v -> 0?

That makes no sense.

I'm sure the ignitor allows a ground through it to fire the coil.. but thats not what i'm asking.
I'm asking how to make the ground circuit open!