Alpha-N on a Microsquirt and 2stroke engine

For discussing MicroSquirt (TM) configuration and tuning of fuel parameters (including idle valves, etc.).
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SQLGUY
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Re: Alpha-N on a Microsquirt and 2stroke engine

Post by SQLGUY »

I actually would try increasing the cold priming pulse time first.

While the Megamanual does say that it's only for purging air, there are other posts from Lance (http://www.msefi.com/viewtopic.php?f=31&t=31757) that say it's actually useful for wall wetting when starting cold. The same post also recommended not going too far with ASE/WUE when trying to provide that initial startup fuel.
hybrid
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Re: Alpha-N on a Microsquirt and 2stroke engine

Post by hybrid »

Yeah common sense said to me that we need to be careful using WUE and ASE for this because once the bike starts, it doesn't need too much fuel any more.
Is there a maximum pulsewidth that we can specify for the priming pulse?
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grippo
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Re: Alpha-N on a Microsquirt and 2stroke engine

Post by grippo »

You can prime for several seconds, but I wouldn't go anywhere near that long. Try raising the prime pulse in MT. If it limits you, you can go in the ini file and modify the maximum, but increase in reasonable increments.
hybrid
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Re: Alpha-N on a Microsquirt and 2stroke engine

Post by hybrid »

Thanks Grippo!
I really think even 1 seconds worth of priming should be enough.
With the spray bottle, I normally just do a couple of squirts in each TB, and that seems to be enough to get it to fire.
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hybrid
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Re: Alpha-N on a Microsquirt and 2stroke engine

Post by hybrid »

Sorry to dig up an old post again, but I still can't seem to get the priming pulse to change.
I would like to try about a second of priming pulse when the engine is very cold to start my 2 stroke, but I really think I'm lucky to get 100ms out of it.
To get the bike to start at the moment, I have to turn the key on and off about half a dozen times before I try to kick start it, before it will fire.
I've switched priming pulse to use a table, but it seems to be ignoring what I enter there.

Has anyone else managed to get fairly high priming times?
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grippo
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Re: Alpha-N on a Microsquirt and 2stroke engine

Post by grippo »

I'm sorry but I was wrong about the priming pulse. Although you can set it to over a second, it is sent through the pw variable which is in microseconds, and so can only hold 65 ms (65000 us). Plus the cpu output compare register can only hold this amount. The easiest way to do this would be to add a no. prime squirts to the logic and keep looping for this no. times. I will put it on the list, but right now I am only putting additions into the sequencer code (3.x code). This is back compatible with MS2 and microsquirt, but involves quite a few changes in the code, inputs and ini file. This has only come up once before several years ago.
hybrid
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Re: Alpha-N on a Microsquirt and 2stroke engine

Post by hybrid »

Thanks Grippo, that makes sense.
I guess I'll have to put up with turning the key on and off several times for now.
I've even thought about putting a push button somewhere that I can use to prime the injectors for initial startup. Dont really need any more wiring on the bike though :lol:
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- MS1 V3 Powered Ford 351CI V8
- MS2 SMD Powered 307CI Holden V8
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