Ken,

Thanks for sharing your experience.  I have also been experiencing some
troubles that I think may be due to a bad fuel pressure regulator.  I have a
1982 air cooled Westy (Federal model) that has been really hard to start
when cold for a couple of months now.  It appears to be running too rich,
then as it warms up everything is good and it runs great.  I e-mailed the
list about this a while back and most of the suggestions centered around the
cold start valve, thermo time switch and auxillary air regulator.

I checked the entire FI system per the Bentley, both at the actual component
and through the wiring harness and everything checked out according to
specs.  The last thing I measured was the fuel pressure.  It turns out that
the fuel pressure is about 5 psi too high when the engine is cold, and then
comes down perfectly to spec as the engine warms up.  I am thinking that the
too high fuel pressure when cold is causing the mixture to be too rich
leading to the hard starting condition.  Sometime after Christmas I will
pick up a new regulator and see if this takes care of the problem.

Happy troubleshooting,
Jake

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
Ken Wilford
Sent: Wednesday, December 14, 2005 8:00 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Crazy intermittant rich running finally solved!

A customer recently came in needing an engine rebuild.  He also wanted
me to replace almost everything else in the fuel injection system and
ignition system.  He had actually accumulated the parts already so I
just installed what he had.  New AFM, distributor, cap, rotor, plug
wires, plugs, filters, ground strap, and temp sensors.  However after
the new engine was installed the van would exhibit a Jekyl and Hyde
personality.  It would run great for a few days.  Then it would run
really badly (rich) making a put-put-put sound.  Then for no apparent
reason, it would run great again.  I swapped in my digitool ECU and it
ran the same.  I couldn't see any readings on the digitool that were
really out of line with normal.  When it was running great or running
bad the readings were the same.  Finally after pulling my hair out for a
few weeks, I decided to replace the entire engine wiring harness.  But
first a voice told me to check the fuel pressure.  I checked it and it
was 7 psi higher than it should be.  Also the pressure was bleeding down
rather quickly after the engine was shut off.  I tested per Bentley and
found that the Fuel Pressure Regulator was the bad.  Installed a good
used one and now the van is great!  No more J and H!  I think what was
happening was that the fuel pressure was just high enough to be right at
the limit of where the fuel injection could compensate for the richer
running and allow the van to run decent most of the time.  But then
sometimes the pressure went just a little higher and the fuel injection
would go haywire trying to compensate (thus the rich
running/put-put-put).  Just my theory.

Just wanted to pass this on to the list.  If you have been testing your
sensors and they are all reading good, check your fuel pressure before
banging you head against the wall.

Ken Wilford
John 3:16
www.vanagain.com