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air cleaner sensor leaks [message #324711] Sun, 08 October 2017 16:00 Go to next message
captjack is currently offline  captjack   United States
Messages: 271
Registered: February 2010
Location: Sebastopol, California
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Senior Member
I'm tracking down vacuum leaks on my 455.

The flap that allows warm air from the manifold to get to the carb and help during startup is controlled by a sensor mounted in the air cleaner assy.

I found that the sensor seems to work properly in that when the engine is cold, vacuum passes to the flap controller and operates it causing warm air to enter the engine. What I also found was that when the sensor warms up it does cause the flap to release as it should, but the sensor then leaks vacuum when it's warm. It's not a whole lot, but more than I would have expected. I would expect it seal off the vacuum. Is this usual or is the sensor bad?


Jack Christensen - K6ROW, '76 Glenbrook/Clasco - "The Silver Bullet", Sebastopol, CA
Re: air cleaner sensor leaks [message #324714 is a reply to message #324711] Sun, 08 October 2017 17:32 Go to previous message
pjburt is currently offline  pjburt   United States
Messages: 436
Registered: February 2016
Location: Fresno, California
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Senior Member
Jim, I doubt it is supposed to leak. If you need one I've got one I'll send you.

Jerry Burt Fresno, CA.
73 Gmc 26' Canyon Lands
Members: FMCA - GMCMI - GMCWS
A truly happy person is one who can enjoy the scenery on a detour.
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