[Vwdiesel] injector testing

Mark Shepherd mark at shepher.fsnet.co.uk
Mon Apr 18 18:18:13 EDT 2005

I have the use of an atomizer flow test stand at work that
we use to test
the break pressure and flow pattern of the atomizers that
are in the jet
fuel starter for the F-15E.  My question is with some simple
fittings and an
old injector line I can hook up to the tester, the only
thing is the
injector bypass fittings. Do I just put some hose on them
and let them run
the extra fuel out back into the holding tank?



In a word 'yes'
The volume of fuel should be something near zero; having
recently striped down my first injector for use in a
compression tester I have found that the bleed fuel comes
from the squeeze between the injector needle and the tubular
nozzle it slides in. It is a fine fit  and if held
vertically (nozzle and needle) the needle will very slowly
slide down. The diesel is a slowly passing lubricant.The
fuel gets to the front of the needle by means of a single
micro bore down the side of the injector body effectively
just under the 'skin'...
(Strip one down and take a look... amazing) When a bleed
line splits and volumes of diesel comes out; it is 99% from
the 'return' banjo on the outlet of the pump. Squeeze the
banjo to injector line and see your leak disappear!
MTM(UK) (No not Mary Tyler Moore!)

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