EFE (Early Fuel Evaporation) Valve Questions

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Goldie Driver

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Hoping someone here can answer 2 questions about the vacuum operated PS side exhaust valve for me.

Is the valve a spring open, vacuum close design ?

Should there be vacuum present to the actuator when the engine is fully warmed?

Trying to diagnose a WOT clatter that has been present since I got Goldie (1980 K15 Suburban, Federal Emissions).

Thanks !

Britt
 

Goldie Driver

Full Access Member
Joined
Mar 19, 2018
Posts
3,925
Reaction score
6,375
Location
Houston, Texas
First Name
Britt
Truck Year
1980
Truck Model
GMC K1500 Suburban
Engine Size
350
Well, from a 75 - 82 Chilton's:





So, I think I will leave the vaccuum line disconnected and plugged since I discovered vacuum this morning on the line while the engine was fully warmed up ( after 27 or so miles of driving)

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