Digging up an old thread here, now that I've started looking at this again.
There's a couple things I don't understand.t
"Early injection starts as soon as the intake valve closes", doesn't this mean
you're firing onto a closed intake valve, making a puddle? The intake valve
closes at 49° ABDC (that's 229°, right?). Wouldn't one want to end the
injection puls right before the valve closes, instead of starting it on a
closed valve?
"late injection starts after the TDC when the intake valve has already started
to open". The 99 intake opens at 8° BTDC, so you're injecting at a couple
degrees ATDC?
Currently my settings are such that when cranking, my pulse ends at 2° and when
running at 229°. Does this make sense?
Frank
Auteur: Ray Ayala
Datum: 2009-11-12 15:372009-11-12 14:37 +100UTC
Aan: Eric Schieb, miatapower
Onderwerp: Re: sequential fuel
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: miatapo...@???
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: miatapo...@???
> 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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