New wasted spark coil w/drivers (beta)

[KneipeMeijer]

Hey guys i have a question where does the black and white wire go?

[KneipeMeijer]

GM ignition coil from their V6 models, maybe DIY has characterized them for dwell vs amperage and output. Like GM's LS coils, it'll have internal driver circuitry from the factory. Typically if it has 4 pins for one coil it has an internal driver, this follows that logic with 6 pins for 3 coils.

• primary +
• primary -
• signal -
• signal a +
• signal b +
• signal c +

So for what i understand is
Primary + (Switched power from coil)
Primary - (Chassis ground/ battery ground ?)
Signal - (Negative wire coil ?)
Signal a + (ECU)
Signal b + (ECU)
Signal c + (ECU)

Could someone confirm this?

[varg]

So for what i understand is
Primary + (Switched power from coil)
Primary - (Chassis ground/ battery ground ?)
Signal - (Negative wire coil ?)
Signal a + (ECU)
Signal b + (ECU)
Signal c + (ECU)

Could someone confirm this?

Signal - should go to the ECU ground plane but yes, it's triggered by a switched +5V signal. Or at least it's typical of most logic level signal controlled coils. If this one is different for some reason hoffbrohaus can correct me.

[KneipeMeijer]

Alright got the coil today, I am trying to install it into my k-data (KDFI 1.4) ecu. Hope Hoffbrohaus could confirm.

[Hoffbrohaus]

Alright got the coil today, I am trying to install it into my k-data (KDFI 1.4) ecu. Hope Hoffbrohaus could confirm.

Confirmed and what varg said. I took the coil wires and taped the coil ground wire off. (previously i did that wrong and fried the board) Then I ran Primary+ to the switched coil power wire.

The Primary- then ran to the chassis ground on the shock tower.



all the rest, 4 wires, I fed through the firewall into the glovebox to run to the ecu. Signal- (black) is going to "signal ground" pin 22 on the mspnp2.

[KneipeMeijer]

Got the coils working yesterday, The only problem is that i took the switched ground from the fuelpump which is not ideal because now the fuelpump keeps running when the key is turned to the on position. The only problem i got is that i cant find a switched ground which is not used, does it need to be a switched ground or could i take a main ground from the ecu?

[Hoffbrohaus]

Got the coils working yesterday, The only problem is that i took the switched ground from the fuelpump which is not ideal because now the fuelpump keeps running when the key is turned to the on position. The only problem i got is that i cant find a switched ground which is not used, does it need to be a switched ground or could i take a main ground from the ecu?

Uhh we might need varg on this one. I didn't think there was such a thing as "Switched" ground. The ground is grounded all the time, whether power is on or off. So i looked up "Signal" ground vs "Chassis" ground. It looks like the only difference is "Signal" ground is usually on the ECU and just a cleaned up ground with no noise, but eventually connects to the chassis ground anyway. So I would think any ground on your ECU would work. Your switched power should be coming from the coil switched power wire.

Primary + (Switched power from coil)
Primary - (Chassis ground)
Signal - (ECU ground)
Signal a + (ECU)
Signal b + (ECU)
Signal c + (ECU)

[KneipeMeijer]

I didn't think there was such a thing as "Switched" ground. The ground is grounded all the time, whether power is on or off. So i looked up "Signal" ground vs "Chassis" ground. It looks like the only difference is "Signal" ground is usually on the ECU and just a cleaned up ground with no noise, but eventually connects to the chassis ground anyway. So I would think any ground on your ECU would work. Your switched power should be coming from the coil switched power wire.

That's what I thought but I am not sure, everything else is connected except the signal ground.

[varg]

A "switched" ground would be something you wire in or an ECU function. It's common to ground the coil of a relay to turn it on when fused 12V is easily available near the relay, and the ECU grounds the fuel injectors to fire them, for example. It's often preferable to switch relays by switching ground because you can run a wire to any chassis ground in the cabin to the switch then through the firewall to the relay with zero risk of ever grounding out a +12V and less effort than finding one to splice into.

Signal ground on the internally driven coil is just grounding the "signal -" on the coil driver transistors to the ECU ground plane to avoid noise and differences in ground potential between the ECU and coil primary ground either via wire resistance or ground connection resistance. With megasquirt for example that signal - would go to any generic ground wire pin or directly to ground plane. You'd wire in a 4+ pin auxiliary connector with a signal - to some ground plane position on the board, and the 3 outputs necessary to control the coil drivers. Take notice that with the car running, if you were to take your multimeter and measure voltage between the ECU ground plane and the strut tower ground for example, you may not see zero, this is why you ground a sensor or a coil driver to the ECU directly.

[KneipeMeijer]

Thanks varg for the clarification, wired the signal ground directly to the main ground on the ecu and got it working only thing left is to fabricate a bracket for the coil.