[RobertZalewski]

My engine is "PARALLEL TWIN ENGINES", shown as 360* in these graphics

[jonbill]

Port vs throttle body setting is currently ignored.
Both are therefore attempting to use 2 channels. If even fire is set, those two channels are 180 degrees apart , if odd fire then whatever angle you set between channels.
Given you're only using one channel:
With wasted spark, each ign channel fires every 360 degrees. Each injection channel should fire every (720/squirts) degrees.
Because you have set 1 injector, both inj channels will be firing for twice as long as they would be if you had 2 injectors.
So I think it really should work.
The only opportunity I see for the startup lottery is where that inj 720 starts. 1/2 the time it will be on cylinder 1 inlet and the other half on cylinder 2. But with 2 squirts I think it must be even for both cylinders over the whole 720.
Hopefully @noisymime will have some ideas.

[RobertZalewski]

I use speeduino v0.4.3d because I am building an engine with a head where each cylinder will have its own intake channel. There will be 2 injectors and maybe 2 additional ones staged. But that's the future, for now I want to solve a single problem. I am attaching the cable diagram.

[PSIG]

Not looking to go sideways here, but clarify exactly what Speeduino does in each case. To use a setting effectively, such as this project, we have to know (or know what to reasonably expect) what it will do. Not attempting to derail anything, but this thread is as good a place for it as any, I think. This would also help update the old behavior how many injections of how much fuel on what sparks, when, depending on settings (chart at bottom).

Just to confirm behavior:

If even fire is set, those two channels are 180 degrees apart ,

I have not examined code as you have, but I assumed Even Fire was (effectively) 720°/nCYL, making a 2-cyl 720/2 = 360° firings by default?

With wasted spark, each ign channel fires every 360 degrees.

Yes, firing both cylinders using the same crank angle concept as fuel above?

Each injection channel should fire every (720/squirts) degrees.

It should, and at divided fuel for identical total fuel to each cylinder, but does it, in code or reality? My test rig is packed-away, so I can't test current code. While the OP could use slow-motion video of LEDs, or 'scope or data analyzer, the expected or intended behavior should be clear and documented, IMO. This should answer the OP directly and confidently.

[DO NOT USE THIS CHART] Settings behavior (old) from 2019, needs updating and more cyl counts, or logic to extend to other cyl counts. All settings should result in identical fueling to each cylinder, just at different times or numbers of squirts across the cycle:

Speeduino Alternating-Simultaneousk effects.jpg (397.09 KiB) Viewed 1888 times

https://postimg.cc/K3vnZhZr

[noisymime]

OK, thanks for the clarification. In your current arrangement I would try the following settings:

• Squirts per cycle: 2 (You need at least 2, 1 will cause all sorts of issues with the single injector/shared inlet arrangement)
• Engine Type: Odd fire
• Channel 2 angle: 0 (If you had a cam sensor, 360 would be fine)
• Injector Layout: Paired

That should allow you to use the single injector and a wasted spark ignition layout.

This is specifically for what you've described as your current setup. The changes you're talking about with a 2nd injector, different inlet arrangements etc WILL mean you need to change these, but it should be right for your current setup.

[RobertZalewski]

Thank you very much for your replies. I will test this setting in the near future and, of course, I will let you know on the forum whether the error has disappeared.

1. Can you explain what changes changing from 360 to 0 degrees channel 2?
2. If I only use INJ1, does channel 2 work on INJ2? (which I don't use, of course, because I have one injector).
3. Does changing such key information require re-tuning?

[RobertZalewski]

In this engine, ignition must occur every 360* on both cylinders.

[jonbill]

In this engine, ignition must occur every 360* on both cylinders.

That sounds like its a 2 stroke. Surely not?
From the picture earlier, the pistons move together, but fire 360° apart, is that right?

[jonbill]

If even fire is set, those two channels are 180 degrees apart ,

I have not examined code as you have, but I assumed Even Fire was (effectively) 720°/nCYL, making a 2-cyl 720/2 = 360° firings by default?

I don't have my laptop with me, so I can't double check right now, but I think that although thats what you'd expect, the code assumes 2 cyl is the front half of 4 cyl, with the crank throws 180 apart and thus even fire is 180.

With wasted spark, each ign channel fires every 360 degrees.

Yes, firing both cylinders using the same crank angle concept as fuel above?

No, because the code uses 2 channels for 2 cylinder engines. So firings on a given channel are 360 apart but the 2 channels are 180 apart.
I think this is what makes this hard to think about - it conceptually really only needs one channel, the user has only wired up one channel, but the code is using 2 channels.

Each injection channel should fire every (720/squirts) degrees.

It should, and at divided fuel for identical total fuel to each cylinder, but does it, in code or reality?

This is why I asked Josh to take a look at this thread. The code is quite opaque on how the number of squirts is calculated. The number of squirts field in TS isn't given to us/speeduino; TS uses it and creates a variable called 'divider' that we can see to calculate the number of squirts. This resulting nsquirts is stored and I think should be logged but I haven't found it yet
The OP has observed his engine runs correctly more often with squirts set as 1 in TS, which makes me doubt the speeduino calculation.

[RobertZalewski]

In this engine, ignition must occur every 360* on both cylinders.

That sounds like its a 2 stroke. Surely not?
From the picture earlier, the pistons move together, but fire 360° apart, is that right?

Yes, combustion occurs at 360*
It sounds like a two-stroke, but it's a four-stroke