Date:         Wed, 27 Jul 2011 22:13:35 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: dumb fuel injection question
Comments: To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
In-Reply-To:  <008d01cc4cad$d529ee90$6401a8c0@PROSPERITY>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 06:37 PM 7/27/2011, Scott Daniel - Turbovans wrote:
>'The only' variable is how long, in milliseconds the ecu holds the injectors
>open.
>( minor variation is fuel pressure, which changes slightly relative to
>intake manifold vacuum ...as affect by the fuel pressure regulator  )

Actually the fuel pressure is *not* a variable, since the function of
the fuel pressure regulator is not to maintain a constant gauge
pressure but rather a constant pressure between the fuel rail and the
end of the injector (which is inside the intake manifold).  Because
of that the injector passes a constant amount of fuel per millisecond
even though the manifold pressure varies over a range of close to 15
psi and may be varying even while the injector is open.

Yours,
David