Before doing fuel flow checks replace filter.  That was actually in the
instructions for one pressure checker I had.
jimt

On 6/9/05 5:50 AM, "George Goff" <THX0001@AOL.COM> wrote:

> In a message dated 6/9/05 12:53:36 AM, maxjoyce@IPA.NET writes:
>
> << Starts off like the specs say it should, but gradually the max pressure is
> around 28 and  decell(high vacuum) low 20's.  Could this be grunge in the
> intake coming from the tank . . . >>
>
> Max,
>
> I imagine you are using the fuel supply pressure test point to take your
> measurements and the fuel pressure regulator appears to be working as it
> should,
> although at a lower system pressure once hot.  If so, I would next test the
> output pressure of the fuel pump, both cold and hot, with the pump dead-headed
> to
> a pressure gauge.  Take adequate precautions with your test setup because a
> healthy fuel pump will produce a much higher pressure when dead-headed.
>
> I doubt if some crud would affect the output pressure of the pump as much as
> restrict the flow.  Still, if you do a pressure check, you should certainly
> test the rate of flow both cold and hot.  The proper rate of flow is probably
> noted in the Bentley, but, for your purposes, all you really have to look for
> is
> a markedly different rate between the cold and hot measurements.
>
> Being electrical, the motor of the fuel pump might be suffering some drag
> once it heats from running under load.
>
> George
>
>