Date:         Thu, 10 May 2001 23:11:14 EDT
Reply-To:     Wolfvan88@aol.com
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Robert Lilley <Wolfvan88@aol.com>
Subject:      Re: Gas Milage and the Fuel Pressure Regulator
Comments: To: dbeierl@attglobal.net
Content-Type:  multipart/alternative;

Thanks,

When I was testing different pressures and methods to decrease the vacuum,
changing the pressure had a direct effect on power and mileage.  If I set the
pressure too low, based on setting the low pressure with the vacuum attached,
it ran hotter and lacked the power I expected.  When I removed the vacuum
hose the high pressure was lower than stock psi.

When I then set the pressure to the high psi without the vacuum hose, it ran
better but still seemed to lack full power past 4500 rpms, like it was
leaning out. It would make it to 5000 rpms but seemed to not have the same
punch at higher speeds as during lower speeds.

When I disabled one of the vacuum diaphragms in the dual fuel pressure
regulator, as I revved the engine, the fuel pressure did not drop as low as
when both diaphragms were active. There was increased power above 4500 rpms
and increased power in the lower rpms also.  But before I could test it
future, contaminated gas killed my fuel pump.

You might be talking theory and principles, while I am talking actual effect
and describing what happens not so much as the theory behind how it happens.

I have seen a direct correlation between how and what the settings of my
adjustable fuel pressure regulator are and the performance of my engine.

When I failed my emissions test a year ago, my valves were not closing fully
and causing me to fail the test.
I changed the oil, reset the FPR, did a tune up and checked all possible
sources of vacuum leaks.
I failed a second test.
The third time, I set the valves to .000 (Cromoly push rods do not expand as
much as steel) and that was all and I then passed the test.
The tester was surprised that simply readjusting the valves could lower the
emissions so much. The vacuum leak was fixed.
I then did Boston Bobs procedure to eliminate adjustment problems with the VW
lifters.

There are others that have had air leaks that resulted in vacuum leaks that
resulted in failed emissions that passed when they were fixed.


Robert


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