Mark, I was thinking along the lines of the restrictors in the vacuum lines I seen in the pile of tubing from a couple old cars that I scraped, or maybe a 1/8" piece of steel tubing with a drop of solder in and a hole drilled thru the solder.  The aquarium valve would sure be a simple way to make a restrictor.  JohnD

 

John;

 

That’s essentially what I did, except I used epoxy instead of solder, and used a .050 wire to form the orifice. Then used a fuel filter as an accumulator.  It improved the idle of the engine. 

 

I had also found that using the un-damped MAP signal for the pressure-referenced fuel pressure regulator caused rapid pulsations in the fuel pressure.  I don’t know that this affected engine operation in any way, but decided it could an unknown stressing factor on the fuel system.  Using the damped MAP signal eliminated that phenomenon.

 

All of this is influenced by the location of the MAP measuring ports.  Mine is picked up relatively close to the ports (about 6”) and would likely have stronger pulse than if picked up in an air box at the far end of long runners.

 

Al G.