Proper operation of 3/2 vacuum valve

[yogarda]

Hello All,

Please see the attached pic to help explain my descriptions below.

We all know there has been much discussion of vacuum issues and t-shooting for our deisels. I have read lots of people say their 3/2 valves "do not hold vacuum" or "hold vacuum". In the process of eliminating my own vacuum leaks, I have found that what appears to be the "inputs" to both of mine do hold vacuum when the valve is closed (the lever is not pushed down). My question is, what is the behavior supposed to be when the lever is depressed?

When I plug both of what I would consider to be the "outputs" of the valve, it will still deplete the vacuum I apply to it with the Mityvac, and relatively quickly at that (about 1 second). If I do NOT plug one of the outputs, the vacuum is lost immediately.

My inkling is that with both outputs plugged it should still hold vacuum, simply redirecting it out the other two nozzles. However, to my knowledge, nobody has yet described the expected operation of a working valve in its open and closed states. In fact, I can imagine some folks have applied vacuum to the wrong nozzle and seen a valve not hold vacuum when perhaps it would have on the input.

Elaboration on this point will hopefully help me and others in the future know when we need to drop the $60 to replace a pair of these or not, so your collective wisdom is greatly appreciated as always.

Kindest regards,