Ignition Tuning

[joaocaleira]

Hi,

So i have been trying to solve a problem related with the eletronic ignition in my GX31. I was using a picoscope to calibrate the eletronic ignition, to set it with the same ignition advance as the standard magnet ignition (27 degrees). When i was running it on TunerStudio MS with the eletronic ignition, with a fixed advance of 27 degrees the behaviour is quite diference from the original configuration (with magnet ignition goes until 5800 rpm, and with eletronic ignition goes until 4500 rpm). Even when i tune the table to increase the advance it just goes until 4700 rpm. Does it mean that its not runing with 27 degrees, or can it be for any other reason?

Thanks, regards

[tryingbe]

This the second post for the same issue. Without posting your tune file and log file, no one will be able to help you. http://www.msextra.com/forums/viewtopic ... 57#p514457

Post MSL and MSQ.

[joaocaleira]

This the second post for the same issue. Without posting your tune file and log file, no one will be able to help you. http://www.msextra.com/forums/viewtopic ... 57#p514457

Post MSL and MSQ.

Here it is the file MSQ.

[tryingbe]

How did you generate the spark table? Looks wrong for this engine.

Make a new table.

http://www.useasydocs.com/theory/spktable.htm

[billr]

When you talk about rpm limits, like 4500 or 5800, is the engine under load, or just free-revving? If under load, how much? Torque values would be nice, but even just MAP will give some clues. Yeah, I realize MAP on a single-cylinder engine isn't going to be smooth; but anything is better than nothing. We need that data-log (MSL) along with the MSQ...

I have no clue what you are trying to do with the picoscope, but using any kind of scope to look at or evaluate the effects of spark timing seems cumbersome and maybe unreliable compared to using a simple timing light. Have you used a timing light to determine spark advance at a few rpms/load conditions using the stock ignition system? Are you using a timing light to verify what timing is with the MS?

[joaocaleira]

How did you generate the spark table? Looks wrong for this engine.

Make a new table.

http://www.useasydocs.com/theory/spktable.htm

Im going to aplly this table and see wich results it brings on a MLV file. thanks. But imagining that it is working with the electronic injection with a fixed timing equal to the one of the magnet ignition (27 degrees) it should have the same performance right? in terms of being able to get to the 5800 rpm of the original configuration.

[joaocaleira]

When you talk about rpm limits, like 4500 or 5800, is the engine under load, or just free-revving? If under load, how much? Torque values would be nice, but even just MAP will give some clues. Yeah, I realize MAP on a single-cylinder engine isn't going to be smooth; but anything is better than nothing. We need that data-log (MSL) along with the MSQ...

I have no clue what you are trying to do with the picoscope, but using any kind of scope to look at or evaluate the effects of spark timing seems cumbersome and maybe unreliable compared to using a simple timing light. Have you used a timing light to determine spark advance at a few rpms/load conditions using the stock ignition system? Are you using a timing light to verify what timing is with the MS?

The engine is under load, it as a 17x10 propeller. So it works under a constant load.

I dont have a timing light, just was able to get a picoscope. Basically i used two channels, connected to the magnet ignition and the electronic ignition, and saw the timing of each one (eletric discharge). Then i was putting them firing at the same time by changing the ignition offset angle.

So if it doesnt arrive to the original performance, of 5800rpm at full throttle, it means the electronic ignition is not actually working with the 27 degrees of advance like the magnet ignition right?

[tryingbe]

Im going to aplly this table and see wich results it brings on a MLV file. thanks.

How are you monitor fuel use? (Running rich or lean?)

Post your new MSQ file after you apply the table. Don't forget to adjust you VE table to pass beyond 4000rpm too.

[joaocaleira]

Im going to aplly this table and see wich results it brings on a MLV file. thanks.

How are you monitor fuel use? (Running rich or lean?)

Post your new MSQ file after you apply the table. Don't forget to adjust you VE table to pass beyond 4000rpm too.

Dont have a oxygen sensor to control the AFR. But yes i can also increase the VE and hope it can go until what i need.

[billr]

When you use the scope, are you connecting the scope probe to the spark-plug high-voltage? If not, and you don't also have a channel that shows TDC, you don't really know that either ignition is firing at 27 degrees or any other specific crank angle. A timing light is pretty much a necessity for playing with engines, get one and avoid wasting any more time. Yes, the considerable difference in power indicates timing is different, kind of proving that your scope method isn't working well...

PS: I envy you being able to put a prop on it and apply steady-state load! I wonder how big a prop I would need for my 427 BBC?

[tryingbe]

Dont have a oxygen sensor to control the AFR. But yes i can also increase the VE and hope it can go until what i need.

You are much braver than I am. I would not dare to tune without an oxygen sensor and a knock sensor.

Good luck with your project.