How do I bench test a “Vacuum delay valve” aka “one way valve” in the EVAP system?
Subscribe96 Maxima - This part is along the vacuum line between the Purge control solenoid and the throttle body. It is black and white in color, cylindrical in shape, and made of plastic with dimensions of 1” diameter x ½” thick and has two vacuum posts. Do you know how to bench test this valve? It sounds like a check valve with a restricted opening and I could not find a test procedure in the FSM.
Senior Member
If it is the part I think it is, you suck on one of those vacuum ports and air comes through. Suck on the other one and you should not get air.
With a vacuum pump (10"hg), I get flow in both direction. There is more resistance when vacuum is applied on the manifold side than on the solenoid side. It looks like the valve is defective.
Thanks,
Thanks,
Member
Here's what the one on my car does: with the vacuum pump on the black nipple and a vacuum gauge on the white nipple, I can pull a vacuum on the gauge attached to the white side by pumping the pump. If I flip the valve around, it doesn't allow vacuum to be pulled in that direction. So vacuum applied to the black side transmits to the white side, but not the other way around. The white side connects to the solenoid valve, black side connects to the intake manifold.
The FSM never mentions this valve.
The FSM never mentions this valve.