So I'm running residual pressure tests with a fuel gauge installed.

The system holds pressure for 10 minutes then very slowly drops. After
about 45 minutes, at 20 PSI, I bled off pressure at gauge. Using FP
relay bypass switch, if I turn the fuel pump on for 2 - 3 seconds then
off, system pressurizes to ~ 40 PSI but then pressure rapidly drops to
0 in less than 5 seconds. Clamping supply hose stems this pressure
loss. I assume this is being caused by the check valve in the pump

I doubt it but.... does the check valve in the Vanagon Bosch fuel pump
require pressure to be maintained for a certain period of time before
the check valve is actuated? And, if the pressure drops too far for
engine to start easily, and the pump (normally) only primes for one
second, in my case, it seems the check valve isn't able to keep
pressure.

On 3/2/14, Neil N <musomuso@gmail.com> wrote:
> Right, ok. I should mention now that this is in regards to a Jetta 2.0
> in my Vanagon. A3 Bentley says to clamp the fuel return hose. If
> pressure holds, regulator is at fault. If pressure drops, pump check
> valve at fault.

--
Neil n

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