Date: Sun, 4 Jul 2004 15:50:20 -0700
Reply-To: Craig Oda <craigoda@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Craig Oda <craigoda@GMAIL.COM>
Subject: Re: low fuel pressure and lean engine
In-Reply-To: <40E82EF5.9040803@earthlink.net>
Content-Type: text/plain; charset=US-ASCII
Mark,
thanks for the information. Also, thanks to Boston Bob for his tip
about setting the RPM to 2,000 during the tests.
There is little pressure change when I close the fuel pressure
regulator line. Also, I tried disconnecting the vacuum line that
controls the fuel pressure regulator. No change. Finally, I swapped
another fuel pressure regulator into the system and the problem still
exists. Actually, pressure is now more like 15psi to 20psi, no longer
25psi.
I went to Kragen to buy a fuel filter. Even though I changed the
filter about 1 year ago, it's cheap and I thought it would be worth
the cost. Unfortunately, Kragen sold me one that doesn't look like it
will fit. Maybe it is for before the fuel pumpt? It's a square
plastic white one and my current fuel filter is like a fat beer can
with no label, kind of a shiny aluminum look. The fat beer can filter
goes inline after the fuel pump.
I'm about to buy a fuel pump from volkscafe. They seem pretty
friendly and knowledgable. Also, they're pretty close to my
house/garage.
I've done a basic leakdown test on my fuel system and it looks like
it's holding pressure for about 10 minutes or so. I can't smell any
gas leaks or see any gas dripping.
I checked the grounds and voltage on the existing fuel pump. Seems to
be rock steady at 12VDC while the engine is running. I was hoping
that maybe the grounds were corroded and that the pump wasn't getting
enough volts. Seems to be getting the volts, just not delivering
enough pressure.
So, I'm going to spend the bucks on a new pump and see how it goes.
More cash going toward the van adventure. :-(
Regards,
Craig
On Sun, 04 Jul 2004 09:23:17 -0700, mark drillock
<drillock@earthlink.net> wrote:
> There are 3 hoses to the "T" shaped regulator. 2 are across the top of
> the "T" and these are the regulated lines from each head's injectors.
> The other line is where the excess fuel and pressure is released back to
> the fuel tank. This is known as the return line. If you hook up the
> pressure gauge and watch it while you pinch the return line closed you
> can tell if the low pressure problem is with the regulator or
> elsewhere.This pinching prevents the regulator from working and lets you
> see what pressure the fuel pump could make by itself. If the pressure
> shoots up with the return line pinched then the low pressure problem is
> with the regulator. If it does not, then the fuel pump may be at fault
> as the pump should be able to greatly exceed the nominal regulated pressure.
>
> The pinch test only tells something about the regulator when the
> pressure is truly below the regulator's spec. Even a properly working
> regulator will show a pressure rise with the return line pinched. We are
> only checking to see what is causing a known low fuel pressure issue.
> Of course this assumes that your pressure gauge is reasonably accurate.
>
> Mark
>
> Craig Oda wrote:
>
> >....
> >My fuel pressure is about 23-24psi at idle when the engine is hot.
> >This is 5 to 6 psi lower than the pressure recommended in the Bentley
> >manual. Is this the fuel pressure regulator? I've got a spare fuel
> >pressure regulator from a _used_ engine that I can swap in tomorrow to
> >see if it will help. Of course, I'm not sure if the used regulator is
> >good or not....
> >
> >
>
>
