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Subject: Re: [FlyRotary] Re: With great power comes...the ability to muck things up
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From: dmlobner@gmail.com
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Date: Wed, 16 May 2012 14:00:13 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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I'm very interested too.  I'm planning on putting a mega squirt 3 in my car a=
nd probably airplane someday...

On May 16, 2012, at 11:56 AM, Mark Steitle <msteitle@gmail.com> wrote:

> Ernest,
>=20
> Great diagnostics there.  Let us know how the MegaSquirt works out.
>=20
> Mark
>=20
> On 5/16/12, Ernest Christley <echristley@att.net> wrote:
>> I cleaned the plugs, but they just kept getting flooded, and despite the
>> modifications I made to the intake manifold, I
>> was still getting fuel pooled in there.
>>=20
>> I moved on to checking the spark.  The timing light was only flashing
>> occasionally, and I noticed that my VR sensor was
>> mounted so that it was almost in front of the toothed wheel.  I have some=

>> new tools I didn't have when I originally cast
>> the mount, so I cleaned it up, and trued it.  Timing light was still
>> sporadic.  Plugged the wire into a scrap spark plug
>> and sat it on the engine while I cranked.  Nice, consistent blue-white
>> spark.  May have been there all along, but at
>> least my VR sensor mount looks nicer.
>>=20
>> I've got new fuel, good compression, and good spark.  Deep breath, back u=
p,
>> and compare what I have now to what I had
>> when it was running back in November.  I consult TunerStudio (the user
>> interface I'm using to my engine controller).
>> The only thing significantly different is that I converted from using
>> Speed-Density to Alpha-N.
>>=20
>> Background:  MegaSquirt has several, user-configurable ways to determine h=
ow
>> long to have the fuel injectors spray. One
>> way is to measure the manifold pressure and combine that with the RPM.
>> Another is to look at where the throttle is and
>> combine that with RPM.  Both are just secondary measurements of how much a=
ir
>> the engine is swallowing, and have a whole
>> slew of corrections and modifications for various conditions.  Tuning
>> involves filling numbers into a table.  Across the
>> bottom is the RPM.  Up the side is either the throttle position, or the
>> manifold pressure.  For each cell you specify a
>> volumetric efficiency as a percentage.  You've already specified how long=

>> the injectors would spray for a 100% VE cycle,
>> so the cells essentially become a percentage of that value.  By switching=

>> modes, my table no longer resembled reality.
>> Instead of picking up the value of 43 from the table while cranking, it w=
as
>> picking up a different cell that had 93.
>> More than double the required fuel.
>>=20
>> I switched the setting back, and gave it a try this morning.  It took abo=
ut
>> 30 seconds of spinning while it was
>> obviously trying to kick off before it caught up and ran smooth at 1500 R=
PM.
>> It has taken two weeks since I got
>> everything painted and tried start taxi testing, but I'm now back in the
>> game.
>>=20
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:
>> http://mail.lancaironline.net:81/lists/flyrotary/List.html
>>=20
>=20
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List=
.html