drop in fuel line pressure on shutdown

[Phil Payne]

> My mechanic concluded it was a vapor lock problem.  Fuel injector fan is
> working, it's sensor is also working.  Problem seems to be compounded by a
> rapid drop in fuel line pressure on shut down which supposedly hastens
onset
> of vapor lock problem.  Fuel tank check valve is good.  Put on a used fuel
> distributor but pressure still drops rapidly on shut down.  What is
between
> the fuel distributor and check value that would be causing rapid drop in
> fuel line pressure??

System pressure regulator, fuel frequency valve, cold start injector and the
normal injectors.

Roughly in that order.

Some time ago, Scott Mockry discovered that the system pressure regulator is
in fact adjustable - it takes a long Allen key right down the centre to the
far end.  I wanted to see what this adjustment did (it seems to fine-tune
residual pressure) so I messed around with a couple of dead units lying
around the workshop.  In the course of my playing with them, both started
working again.  I put them back on the 'good' shelf, laid the Allen key
quietly back in the toolbox, and had a beer.  One of them's now in F600.

--
  Phil Payne
  http://www.isham-research.com
  +44 7785 302 803
  +49 173 6242039