No Flow through Pressure Regulator

[SJ]

From: "Marc Boucher" <mboucher70 at hotmail.com>

> Using a high-end bicycle pump I was able to more or less test the
regulator.
> It is working correctly.  At a set pressure it opens and lets air pass.
> Based on the pressure gauge built into the pump the best estimate of
opening
> pressure is between 75 and 80 psi.
**** Desperation results in innovations. Bike pump is clever idea.
Specs say system pressure should be 88.5 to 94 PSI.
Injector opening pressure is 62 - 67 PSI
Calibrate your guage. Take bike wheel and pump to walmart and test against a
tire guage. Or attach pump to car tire and pump up to 35 lbs, then test tire
with another guage. I think the spare tire is inflated to 60 lbs, use this
for a calibration test.


> It would seem easy to conclude that the fuel pump is the problem except
for
> a few facts:
>
> 1.) Last week when I began this testing, the pump was producing enough
> pressure to cause return flow.
> 2.) Throughout all the testing, I have yet to get any fuel to flow through
> the top of the fuel distributor.  i.e., I have unscrewed each line to each
> of the 5 injectors.  I understand that it requires high pressure to fire
an
> injector, but even with a moderate amount of pressure, shouldn't there be
a
> flow out of the fuel distributor nozzle (assuming the plate is lifted and
> the line to the injector is unscrewed) ?
**** I would think so. The top chamber is at system pressure or close to it.
The fuel gets to the top chamber via the control plunger . . .which is
raised and lowered by the air-flow sensor plate. Slits in the control
plunger get uncovered as its raised and that allows fuel to flow. Its
unlikely that all 5 slits are blocked with crud. You said that you can raise
the sensor plate and get no resistance . . . . then its not stuck. The CSV
has fuel flow so that means that fuel is getting to the fuel distributor.
You could have the main feed passageway that provides fuel to the plunger
plugged. Fuel is not getting past the plunger.
I've attached 3 photos of typical fuel distributors so you get an idea what
it looks like inside.


> Tomorrow I will reinstall the regulator and see one more time if I don't
get
> return flow.
**** I wonder if you can connect the pressure regulator directly to the fuel
filter. Maybe if you used rubber hoses and clamps.
If you now get fuel flow thru the regulator, that would mean that the fuel
pump is probably ok.


  There are 3 things that I want to check that might have
> changed since last week and would impact the fuel pump's ability to pump
> a.) the state of the battery...I took it off the trickle charger last week
> and with all its been through lately...
***** I told you that fuel flow and pressure are directly related to the
voltage.

> b.) the wire I'm using to 'jumper' the relay...this week I hooked up a
long
> wire so I could be on the other side of the car...it is relatively thin
wire
> (a single strand of cat5 wire) so this could impact
**** Oh yeah, that will cause you problems. That small wire can drop a few
volts. Use 16 guage or lower wires.
>
> Last week I also conducted a flow test as had been noted.  60ml was
> collected in a period of between 1 and 2 seconds.  Taking the worst case
> gives 30ml/second or 900ml in 30 seconds.  I'll try and repeat this
tomorrow
> and measure a full 30 seconds worth, if conditions are a bit safer.
**** Good idea to get these standard tests out of the way. Otherwise, we are
going round in circles. Also make sure you read the voltage at the pump.
Keep in mind that the pump is not working against the pressure regulator
when you are making this test. Under a load the pump may still fail to
deliver what is required.


SJ
85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q