Re: CIS perceptions

[Robert Houk - WorkGroup Server Firmware <Robert.Houk@East.Sun.COM>]

   I don't think so... think about the fuel distribution test.
   Pull them all out, put in graduated test tubes, run the
   pump and pull the air plate up to 'idle' position.
   They ALL squirt continuously - with atmospheric pressure on the
   'manifold' side of the injector.  

   > In normal operation, a (relatively) steady pressure is applied to the
   > fuel supply side of the injector.  As the piston drops during the intake
   > stroke, the pressure on the manifold side drops.  Thanks to time delays,
   > the pressure appears lowest to the injector physically closest to that
   > cylinder.  At some point, the injector opens.  You want a richer
   > mixture?  Increase the pressure.  The fuel distributor varies the
   > applied pressure based on lots of variables, including air & engine
   > temp, O2 sensor readings, engine speed, air mass flow sensor data, etc.

   It's not the pressure at the injector.  It's the pressure difference
   across and size of the metering slit in the fuel distributor that
   determines the fuel flow.

   There is always more than enough pressure difference across the
   injector itself to open it - system pressure is around 90 PSI.

Further, think about forced-induction systems -- there is a *positive*
(which is to say, greater than atmospheric) air pressure at the injectors
(at least, when you are having _fun_).

					-RDH