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Megasquirt settings
Nitrogeno25 - 28/9/12 at 02:10 AM

I started my engine yesterday with a MS2 (extra) with EDIS. The engine is duratec 2.0 with jenvey 45s. It was easy to start the engine but I need to tweak the cold start. The engine starts from cold (I have no fast idle valve) and idle at 600-650rpm. If I let it warm up no problem ad idles at 900rpm. The thing is I can't touch the throttle when cold because the engine stalls. No problemwhe it's warm.

I read that when starting MS uses the cranking pulse width, then after start enrichment and later the VE table, but what happens if I crank the engine with the thrttle open? it should compensate the extra air with extra fuel..

thank you very much!


big-vee-twin - 28/9/12 at 08:24 AM

You have to set cold idle quite high with throttle bodies, my Duratec Idles at around 1100rpm when cold and drops to around 900 when warm, this is set by the adjusting screws on the throttle bodies.


matt_gsxr - 28/9/12 at 09:12 AM

Hi there,

I guess you have two points here:

Regarding the first. I guess the problem is that when cold you only just have enough fuel to keep it happy, then when you add more air it all goes wrong. Why not increase the amount of warm-up enrichment?
Alternatively you already have too much warm-up enrichment, and you map is giving you too much fuel for small throttle openings and so you are giving it too much fuel.

For some reason I suspect the former condition. Either look at the AFR (if you have a wideband or narrowband sensor), or just try adding fuel and see if that makes it better or worse.



On the second point:
When cranking the amount of fuel does NOT depend on the throttle position or the MAP. It does depend on the temperature.



If you haven't got an AFR sensor, then I would suggest getting one. It takes away all the mystery (which is a good thing).


Matt


Nitrogeno25 - 2/10/12 at 12:54 PM

Yes, I have a LC-1 and it seems it's getting lean with some throttle. I can only do one test each day

As for the idle speed, I don't have idle control (fidle valve) so can control much. It's idlling at 650-700 when cold and 1000 when hot. I think I will let it there for now.

As for the LC-1 I saw that the update in tunerstudio is very slow comparing with the gauge. When going on the throttle I can saw lean spikes on the gauge but tunerstudio show this slowly and like half a second later, is that normal?

Thanks again!


baz-R - 2/10/12 at 08:14 PM

there is a setting somewhere where you can adjust the refresh rate (the frequency) of how often the megersquirt views various sensors to stop readings moving all over the place and stay as consent as possible (damped)

i don't really think you need to worry about this too much just run of your gauge


matt_gsxr - 2/10/12 at 09:08 PM

I have LC-1 and get instant changes to AFR in the tunerstudio logs.
LC-1 can provide data at different rates along the analogue output line.
Not sure what the default is, but sounds like you have some smoothing set.

Once this is sorted then I am sure we can sort you out if you upload a data log and your map (msl and msq)