Air intake heat sensor/diaphram

[Wags391]

How far should the diaphram open to let cold air in within the air intake? It's where the pre-heater hose from the exhaust manifold connects to the air intake assembly. Mine is only opening maybe half an inch.

92 Chevy S10 Blazer, 4.3L, Z, TBI, 4X4

[sector95]

Originally Posted by Wags391

How far should the diaphram open to let cold air in within the air intake? It's where the pre-heater hose from the exhaust manifold connects to the air intake assembly. Mine is only opening maybe half an inch.

92 Chevy S10 Blazer, 4.3L, Z, TBI, 4X4

That would depend on how cold the intake air is. The sensor in the air cleaner assembly is set for a specific tempurature; anything below that setting will cause the snorkle flap to open allowing hot air off the exhaust manifold to mix with the incoming air. If the ambient outside air is hot enough, then the flap should open fully. In my Chilton's it indicates a procedure for the vacuum operated system using a thermometer to check the system; the tempurature reading should be 131 deg as the flap just begins to open. If you suspect the system is malfunctioning and allowing hot air into the system when it's not needed then you'd need to test the temp sensor. There are two types of sensors; one mounted in the air cleaner base (vacuum) near the throttle body and a second type (wax pellet) mounted integral with the snorkle flap. The vacuum system will have a vacuum motor mounted visibly on top of the snorkle, the pellet system will not have the vac motor.

mike
85S10

[Wags391]

Thanks a lot. That helps. I think it is working properly. After driving for a while, I looked and it was open all the way, so it must be working. It's quite warm around here right now. Texas.