Tony, looks like I will not be shipping the WUR to you after all.
Good News! I figured I could not ship out my WUR until Tuesday since Monday is a holiday. Figured I had the afternoon to learn something about how I could at least clean it and look for blockage. I found Steven Hauer’s 12 page PDF on how to disassemble, inspect and clean the BOSCH WUR.
Just as suspected, there was a blockage. However, the debris was behind the intake screen in the port. I could hardly get 100 psi to pass through the port. I tried lots of carb cleaner but nothing would dislodge the blockage.
Finally, I got a small stainless steel wire about the size of a needle and treaded from the inside of the WUR through the port toward the screen. A few more blasts of air and carb cleaned and it opened up! I’m just disappointed I didn’t find whatever it was on the cloth I laid on my bench. BTW, the inside of the WUR looked like it was new. Very clean.
Reinstalled the WUR, put the pressure test equipment back on and got the following readings.
System pressure 4.9 bar
Opened the valve to the WUR
One minute: 2.3 bar
Two minutes: 2.6 bar
Three minutes: 2.8 bar
Four minutes: 2.9 bar
It's getting late so I have not yet tested with the engine running to record the pressure with the vacuum line attached. I'll get to that sooner or latter.
Turned off Fuel Pump to record Pressures after five and ten minutes:
5 minutes: 1.5 bar
10 minutes: .80 bar
Start Your Engines
Pulled the test equipment off and reattached fuel lines. And started the engine. Vaaaaroooom! The engine started with no problem. No more bucking or surging. No more popping.
Really pleased at this point. I will have to recheck the timing since I tried to do it when the engine was running on 4.9 or 70 psi!
All the Best,
Brian