Buzzing noise (1996 4runner)

Hi all: I have a 1996 4runner SR5, RWD, 3.4 ltr. After driving it for a while and after it is turned off I hear an intermittent buzzing noise coming from near the engine. It buzzes twice in about a second, then after a couple of seconds it does it again. This goes on for quite some time. It sounds like an "electrical" sound. The actual sound comes from about "one step" in front of the driver side (left side), towards the top of the engine bay, from a black box. Any ideas on what could it be? is it serious?

This has been going on for quite some time now. It does not happen all the time, but it keeps getting louder a little bit at a time. At first I though it was a dragonfly or something like that caught in the engine compartment, we have all sorts of critters here in FL. Anything that will point me in the right direction will be greatly appreciated.

Thank you in advance,

FC

Reply to
Sonoman
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Ours makes a sort of soft 'donkey bray' sort of buzz from the same spot. Same year and engine. It's part of the emissions, nothing to worry about. Ours has done it since we bought it four years ago and it's never had any problems, runs great and has passed two smog checks with flying colors.

Up in that area (according to my Haynes manual) is a charcoal canister, vapor pressure sensor, and VSV for EVAP. (What's that last thing, anyone?)

I just figure it's something depressurizing after being operated for a while, like it should. Or a miniature mule trapped inside, complaining to be let out. ;)

Reply to
Pookerz

Oh! I know! I know!

VSV=Vacuum Switching Valve. It's a valve controlled by the ECU that when energized, can either create an atmospheric bleed (engine vacuum is exposed to open air) -or- allow vacuum to be applied to a device.

-Tim

Reply to
Tim H.

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