Date:         Thu, 3 Aug 2000 16:23:47 -0700
Reply-To:     Daniel Schmitz <djs@gene.com>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Daniel Schmitz <djs@gene.com>
Organization: Genentech, Inc.
Subject:      Re: Thanks again! Fuel pump repair (longish)
Comments: To: Puzerewski <Puzerewski@email.msn.com>
Content-Type: text/plain; charset=us-ascii

Adam,

Please forgive me if I'm not understanding you correctly. The admonition
"should" rarely appears in my emails, but....

You shouldn't be using the cheap, plastic fuel filters in the Vanagon's FI
system AFTER the pump. If you're talking about the "bug" type filters used on
carbureted VWs of years past, those filters are designed for low pressure
applications only (read: carbs). The pump in the Vanagon pressurizes the fuel
lines to around 30 psi, and plastic fuel filters are probably not a good idea
(at least not for very long).

The factory design consists of a plastic pre-filter before the pump (the square
one) and a large, cylindrical metal filter after the pump. The small plastic
filter before the pump is not under pressure, and it protects the pump itself by
filtering out relatively large debris that may accrue in the tank. The larger
metal filter after the pump IS under pressure, and it filters out smaller debris
not filtered by the plastic pre-filter. The metal filter is the one that
protects the injectors, and is specifically designed for high pressure
applications, like the pressurized fuel circuit in VW fuel-injected vehicles.

But, again, I could have misunderstood you, or jumped into the conversation late
enough to have missed something.

If, on the other hand, you are in fact using $100 plastic filters, then they are
probably of sufficient quality to withstand pressurization. :)

Dan

> You could never have too many filters, I suppose...
>
> In my van, the PO has one before the fuel pump, one after, and 2 in the
> engine compartment.  These are all the clear stock beetle types, and you can
> see the crud in them.  I am putting in a new gas tank now, so will cut back
> to one before the fuel pump, and one in the engine compartment....I will
> continue to use the clear ones, for it is easy to keep them in the car and
> they cost $100 apiece.....easy fuel system fix.