Has anyone tried making the dual plugs fire at the same time? I read somewhere the "b" plug fires later in the stroke to help with emissions.

 

It's actually a graduated firing order. At low RPMs, both plugs fire at the same time and above a certain RPM, they fire plug A and then 10* later, it fires plug B and the next ignition event would be the opposite and it alternates like that until it gets below that RPM threshold where it goes back to firing them at the same time.

 

Cool, thanks for the info.

 

Cool, I learned something new today!

 

Things that make you go.... hmmmmm! Interesting tid bit Rudy. Thanks for sharing.

 

That's what I'm here for. Sharing my wealth of useless information one thread at a time.

 

Are these cars SMART or what? Not only do they know how to adjust the firing sequence of the twin plugs, but they reverse the order. I miss the simplicity of my 48 Chevy that started even with the distribution 180* out of phase, but it was no where as much fun as the XFs. How did you find out this fascinating tidbit?

 

Theres no real way for the stock ecu to split it like that.

Each coil is actually 2 seperate coils, with common wiring.
3 wires, positive, ground, and the signal wire. If it fires one, both fire.

 

Me too, I did not not know that Rudy.
This is my 2nd. car with twin spark plugs. The other one was a 1983, Nissan 200SX. I bet it's spark plugs didn't fire sequentially.

Bmorgan, was that a Rotary reference?

 

Sorry to be the bearer of bad news but they're wired separately. The two outside wires are the drivers and the center or common wire is on the ignition circuit.

 

ah, thats sneaky. I must of misread the fsm, lol. Im always used to the coils having the power and ground and 1 signal.

I'd be curious to get a look at a stock ecu ignition map.

 

My thinking was rewiring both packs to one input. But with them alternating that would be more involved.

 

If theres 2 signal wires, then each coil has its own driver. The thing you need to find out is can 1 driver handle the load for 2 coils

 

Only reason I could see someone wanting to do this is if they were going to run a standalone which would invariably be a complete nightmare. HDDP did it but he did it with a Motec unit and had the same 10* offset as the factory ECU did. I can't say that this car has a great ignition system but it's better than quite a few out there and I'd try to keep that aspect there. I especially don't know if I'd want opposing flame fronts hitting eachother at high RPMs.

 

it sounds like a recipe for a disaster.
The aem fic is the way to go for me, at least with this car. My 240, full standalone. But as much wiring and integrated features this car has, best leave the stock ecu in place

 

Wasn't it nice when everything was a little more simpler and you didn't have to worry about all this stuff. It's still the same fuel/air/spark but now it's a lot more involved than just twisting the distributor. LOL

 

for some reason, my brain hates carburetors. I can tune a fuel injected car by sound and smell. but i cant twist a screwdriver to save my life, lol.

 

Yeah, I just brought it up thinking maybe it was a way to make some more power for cheap since emissions are no issue here. The alternating sequence would make that a ***** to do and might not help any. I was thinking old school drag bike twin plug heads.