[Diy_efi] Re: Diy_efi Digest, Vol 23, Issue 4

[Bill Washington]

The fuel pressure regulators/ which return excess fuel to the tank have 
a reference/control line to the manifold to maintain a constant pressure 
differential accross the injectors.
If you trust the pressure regulator, you have no need to monitor the 
fuel pressure in the distribution manifold, unless you intend to vary 
the pressure.
NOTE
     If you choose to measure the fuel pressure in the distribution 
manifold, your measurement will be absolute, or relative to atmospheric 
pressure depending on your sensor, however the fuel pressure will vary 
with the fluctuating air pressure in the intake manifold .........

If you choose to vary the fuel pressure to increase the fuel flow range 
available through a particular injector, be careful! -

    1. the injector spray pattern is set at a defined differential 
pressure across the injector - some injectors may give you a range of 
differential fuel pressures - it is wise to stay within the 
manufacturer's spec to maintain a good spray pattern.
    2. If you choose to vary the fuel pressure use a variable regulator 
so that you still retain the intake manifold pressure reference

Bill

>
>I can't quite read this as a yes or a no to fuel pump pressure control -
>can you give me a binary response :-)
>
>I.E. does fuel pressure sensing/fuel pump control make sense for an EFI
>system or not.
>
>Thanks!
>
>On Fri, 2007-01-05 at 08:00 +0900, Bernd Felsche wrote:
>  
>
>