In my previous post I meant to say that late injection is used (when 
appropriate) to prevent the fuel from sticking to the manifold walls, not the 
cylinder walls ... as well as to prevent puddling on top of a closed intake 
valve.  IMHO puddling is a major factor in low-rpm misfire for a multitude of 
reasons.  Early injection starts as soon as the intake valve closes while late 
injection (used only when the angular-duration of the injection pulses is less 
than 90 deg) starts after the TDC when the intake valve has already started to 
open and air has started moving in the manifold runner. 
  ----- Original Message ----- 
  From: Eric Schieb 
  To: [email protected] 
  Sent: Wednesday, November 11, 2009 7:27 PM
  Subject: Re: sequential fuel


  Ray,

  Can you relate "late as possible"and "early as possible" to engine events?

  I don't do much cold engine work considering most of my work is on race 
  cars.  If it is too cold, they don't come out of the trailer.

  However, for a warm engine, we are typically firing our idle pulses 
  slightly before the intake valve open event and our wide open throttle 
  pulses are ending before the intake valve close event.  I know for a 
  while it was Ford corporate policy to not fire on an open intake valve 
  due to bore wash concerns.

  Eric Schieb


  Ray Ayala wrote:
  > During cold cranking & idle the newest Link chips inject as late as 
possible to provide as little time as possible for the fuel droplets to land on 
and stick to cold cylinder walls.  At other times it injects as early as 
possible to allow maximum time for vaporization before firing.
  >   ----- Original Message ----- 
  >   From: Frank Devocht 
  >   To: [email protected] 
  >   Sent: Wednesday, November 11, 2009 12:47 PM
  >   Subject: sequential fuel 
  >
  >
  >   How exactly is seq fuel set up on the Link (or any other ECU) ?
  >   Does it always inject at the same point in the cycle (where is that?) or 
does it use a rpm/load dependent lookup table ?
  >   Is there a differnent point when cranking / running?  (I remember that my 
Link used to start insanely fast when switching to the chip with sequential 
fuel)
  >
  >
  >   Frank
  >
  >
  > 
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