WUR testing boost enrichment via mityvak
 

Recently rebuilt my WUR,

I am checking the boost enrichment, as I apply positive pressure, via the lower nipple, the mityvak registers 0.5 bar, in turn the fuel pressure drops by about 1.1 bar, this is with in spec and is doing what it should , ie, simulating rich fuelling for when on boost.

Not sure if this a problem though as the mityvac only holds the 0.5 bar positive pressure, for 2 to 3 seconds and then bleeds off to 0, I have checked all the seals in the WUR and the diaphragm is also new and cannot see any issues.

The mityvac should hold pressure. Try using a spray bottle with soapy water, Spray around the mityvac cap any hose joints and the split where the two halves of the WUR meet.Look for bubbles if leaking.

it holds the mityvak for a couple of secs, not sure if this is because there isnt a continuous positive pressure coming in like it would be if on boost will try with soapy water,
I did open the WUR to check and all seemed fine,
When rebuilding the WUR and replacing the diaphragm I had to remove the rivets and use small nut and bolts from the kit, could it possibly leak from the bolts

Make sure the mightyvac is holding pressure first - without the WUR. If it is, you have a leak in the WUR system.
Alan

mightyvak seems fine, holds vacum and positive pressure fine