I've run through my SAI system and all is good down to the valves themselves on each side.
On dead cold startup getting vacuum to the solenoid and it's passing vacuum to each valve (albeit a very small amount of vacuum) and after the minute or so the vacuum stops on each side (solenoid working).
I've applied vacuum with a hand pump and neither valve will hold vacuum and hiss as if there's a leak in them which there may well be.
Neither valve will pass air from the pump side to the head side when the SAI system is energized or not (tried to blow into them manually).

They are either both shot or frozen closed or open. I'm assuming there has to be a pretty good spring holding them closed so exhaust doesn't flow backwards.

Two questions:
Exactly how do these work, does vacuum relieve pressure on a check ball or something to allow the valve to pass pump air?
Can they be cleaned (I've tried a few quick shots of brake cleaner with not change)?

I've searched and found nothing specific but then again usually don't have much luck with the search tool.

Thanks in advance.

 

Bump for a favor.
Would someone be willing to connect a hand vacuum pump to one of their known working SAI valves (the small vacuum connection facing the front of the engine) and tell me if it holds vacuum?
Thanks :-)