Leek Down Test for Elements
 

Can anyone think of a reason why we can not come up with an element leek down test to identify the operational condition if the elements? I would think if they are “shot” they would not hold pressure which is why they will not pump fuel.

We would need to build a “tool” and test new elements, used but good elements, and worn out elements, to get acceptable and service limits.

my thoughts

If you mean to test them while they are still in the IP you would need to remove the Delivery Valve (the small Valve not the outer Body) and hook it to a pressure tester; something like a pop tester. And watch how long it takes for the pressure to drop.
However, pressure testing the Element would not tell you if there is a broken return spring or some problem with the Camshaft, Tappets, or tappet rollers.

The real way they are tested is they are put on an IP Calabration machine and the Fuel quanity for each Element is measured with a Flow Meter or in the old days you actually took a sample of 1000 strokes of fuel and measured it in cm.

Ounce you are sure the IP is putting out the amout of fuel it is supposed to at full load and the IP is nice and hot you do a starting quanity test.

Bad IP elements are not often a problem with IPs in cars.
They are a problem with industrial us where companies store their own fuel. Often the fuel gets contaminated with rust, water and fungas.

A Nominal 10 micron filter (this is the Spin-on filter) will only stop 50% of the 10 micron or larger particles that pass through it. This seems to be OK as long as you are dealing with clean Diesel Fuel. I think the reson is because in 1 hours driving time the whole tanke full of fuel is going to pass through the filter many time.
The starting quanity test is run at a specified low rpm and as I said with the IP and fuel hot. If you Elements are badly worn they will not put out enough fuel during this test.

However, if the fuel a badly contaminated due to the 50% passing through the the sheer volume of particles could cause to damage the IP.