Date: Tue, 14 Sep 2004 01:03:26 -0700
Reply-To: Craig Oda <craigoda@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Craig Oda <craigoda@GMAIL.COM>
Subject: Van Update and fuel pressure gauge report
Content-Type: text/plain; charset=US-ASCII
Since so many people on this list have helped me fix my van over the
past few years, I thought I would give an update on the status of the
van. Well, the tranny problem and fuel/air mixture problem appear to
have been resolved. I'm getting over 18mpg with an automatic tranny
on a 1.9L waterboxer. If people remember, I got as low as 5mpg on
one trip to a campsite in Sonoma when my O2 sensor was causing big
problems. I upped this to 12mpg when I disconnected the sensor and
upped the mpg to 18 when I adjusted the Air Flow Meter spring and
reconnected the O2 sensor. Drove fine to San Francisco on Saturday
for Van-O-Rama. Thanks to BenT for organizing an awesome event. It
was great! Nice people and nice vans. I drove down to Manressa Beach
south of Santa Cruz on Sunday, caught some waves, then drove north to
Half Moon Bay to get hit the beach up there. Highway 280 was just
paved and the weather was especially fine in the SF Bay area.
Fortunately, there are still minor problems with my van that I can
tweak to fight the boredom of overly beautiful California weekends.
I've still got a slight misfire and now my exhaust is making strange
noises. Sounds like part of the catalytic converter may have gone
into the muffler and possibly an exhaust gasket leak. I'm not sure
about the source of the misfire. Might be lifter related.
One interesting bit of info. I was checking fuel pressure with a cheap
JCW gauge and found that the gauge was faulty. I verified this by
tapping two gauges into the fuel system and running the gauge
simultaneously. the 2nd gauge was a mechanical gauge constructed from
a water pressure gauge. Once I verified that the electronic gauge and
mechanical gauge were different, I used a potentiometer to measure the
resistance values of the JCW gauge. I found out that the gauge used
0-100 ohms, with 100ohms corresponding to 100psi. Neat, but the
sender wasn't adjusting the resistance properly. Worse, the sender
resistance was varying, resulting in varying pressure readings on the
gauge.
I swapped in a VDO sender and gauge and now the fuel pressure seems to
be steady at 31 psi. Seems to be a little high, but I'm not concerned
about it right now. If I pinch off the vacuum hose to the pressure
regulator, the pressure does rise to atmospheric.
Lesson: buy good quality guages when they monitor engine health
Regards,
Craig
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