RE: [alfa] re: What is this FISPA device?

["Peter Webb" <webb.p@xxxxxxxxxxx>]

Thats what the vacuum reference tube does.  It increases the fuel pressure
based on manifold vacuum to increase the pressure as demand increases (and
pressure in the manifold hinders delivery) to keep the rail pressure
constant.

EFI pumps also have valves in them to prevent bleed back to maintain
constant pressure against the regulator spring.

-Peter


> -----Original Message-----
> From: owner-alfa@domain.elided [mailto:owner-alfa@domain.elided]On Behalf Of
> Joe Elliott
> Sent: Monday, April 12, 2004 7:17 PM
> To: Alfa Romeo Digest
> Subject: [alfa] re: What is this FISPA device?
>
>
> At 7:40 PM +0000 4/12/04, alfa-digest wrote:
> >Date: Mon, 12 Apr 2004 10:23:36 -0700 (GMT-07:00)
> >From: Stefano Iachella <iachella@domain.elided>
> >Subject: [alfa] re: What is this FISPA device?
> >
> >I've heard that these devices are vibration dampers for pulses
> >in the fuel. I don't really understand it, but I heard it from a
> >mechanic. I have no verification of this, in fact, I don't know if
> >I believe it.
> >
> >Stefano
> >Oakland, CA
>
> For what it's worth, I know that more modern (electronic) sequential
> FI systems usually have such devices.  I can understand that you
> don't want the momentum of fuel in the rail to screw up your fuel
> delivery, and similar issues may apply inside the Spica pump.  What I
> don't understand is why batched injection systems like L-Jet don't
> have these, because I'd think that pulses in the fuel would be a
> bigger deal with all the injectors opening and closing at once.
>
> -Joe
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