[T3] Fuel Primer.Switch..

[Dave Hall]

One of our club members had the same problem and had diligently done investigations into pressure drops in the fuel lines after switch-off, as he needed to reprime the fuel ring each time it was left for some hours.  What he found was that the only thing that allowed the residual pressure to remain sufficient for a quick restart was renewing the hoses. This  led to  a much reduced rate of decay of the residual pressure with time.  He felt this indicated the hoses had become porous to air, while not allowing fuel to leak out.

I had similar conclusions for my own FI Fastback. The cycling of its ignition switch was accompanied by bubbling sounds as air was purged from the fuel lines, until a squeak from the pressure regulator showed it was ready to start.  I never fitted a priming switch, though it would have been worthwhile and simple to do.  In what other way can the fuel hoses draw in air, but not leak fuel, other than through porosity?

Dave
UK VW Type 3 and 4 Club.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.vwtype3.org/pipermail/type3-vwtype3.org/attachments/20180926/a62a2b69/attachment.html>