Date: Sun, 4 Sep 2022 16:26:48 +0000
Reply-To: Richard Koerner <rjkinpb@SBCGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Richard Koerner <rjkinpb@SBCGLOBAL.NET>
Subject: Re: Sorting out mechanical issues 85
In-Reply-To: <CAE_+Nq2gf4=VWdGLn7H8rDAOFs3sgQrELPwc-Dtti9cf4uOPnQ@mail.gmail.com>
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Dennis H. was the guy that explained it to me when I had the problem. Most probably the issue is old fuel tank; gunk builds up at screen at outlet. Fuel pump tries to do the best it can, but the result is cavitation in fuel pump (noisy and the gurgling....and vapor bubbles in fuel downstream, which fuel injectors Hate!) Sure, back-blowing with a clean rubber hose (lung power only) into fuel tank may temporarily dislodge some crud and that is OK for an emergency fix while on the road. But the root cause is probably gunked up screen outlet. Fancy fuel pumps....cheap fuel pumps....they will all cavitate creating noise and poor motor performance. Especially noticeable on hot days or higher elevations as gasoline vapor pressure changes. BTDT. After new fuel tank (new crossover tubes too), my fuel pump is silent, and excellent motor performance.
On Sunday, September 4, 2022 at 09:10:38 AM PDT, Rob <vwrobb@gmail.com> wrote:
I bought an 84 Westy some years back with a real noisy pump. The guy
who sold it to me told me he had tried to figure it out, it was a new
pump & he'd covered it with something to quiet it down but it was
still noisy.
I put a new gas tank in and that cured the noise problem! I opened the
old tank but saw nothing wrong..
Rob
vwrobb@gmail.com
On Sun, Sep 4, 2022 at 6:35 AM Eric Caron <ericcaron96@comcast.net> wrote:
>
> So, both pumps sound unhappy when hooked up though a bit better with the new gas filter.
>
> Is there a good way to bench test my fuel pump to see if quiet when not hooked to tank?
>
> I’d like to know if I just have some loud unhappy sounding fuel pumps or if it is something to do with my tank.
> Concerns me that this new Bosch pump sounds as unhappy as my current Amazon one I just removed.
>
> Considering asking a friend to hook up power from an extra battery I have here, to bench test, but would need to run gas as I test.
>
> Crazy idea?
>
> Why do it?
>
> I’m concerned that crud might be getting to my engine perhaps sticking fuel injectors.
> Also the sound of the pump is creepily like the starting sound of a differential with gears starting to wine. Every time I hear that sound as we come to a stop my heart skips a beat. After loosing three differentials all starting with that sound I just don’t want to hear it every time I go out for a ride.
> Anyone got a new old Bosh fuel pump or a good used one that is quiet?
>
> Eric Caron 85 GL auto
>
>
>
> > On Sep 3, 2022, at 11:34 AM, OlRivrRat <OlRivrRat@COMCAST.NET> wrote:
> >
> > On 3 Sep , 2022, at 8:27 AM, Eric Caron <ericcaron96@COMCAST.NET> wrote:
> >>
> >> I’m planning to try to blow back with air compressor to see if that even temporarily changes the sound.
> >
> > Compressed Air for that purpose should not be more than Lung Pressure >
> >
> > Clamp the hose between Tank & Fuel Pump, connect a long clean hose to that hose & gently blow with mouth
> >
> > as needed to hear bubbles in tank with GasCap removed ~
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