94 4runner strange grinding sound from intake
07-17-2013, 08:38 PM
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94 4runner flap inside MAF sensor making metallic grinding sound from air passing by
I recently picked up a 94 4runner 4x4 automatic with 183k miles on it.
it has some upgrades and i am trying to get a handle of what i'm dealing with.
the biggest issue at the moment is an annoying sound coming from the "cold air" Downey intake.
at first i thought is was a belt slipping but it is too consistant of a noise.
yesterday i took the top off the dewey air box and the sound is definitely coming from the silver box (AFM?) show in the photo. the photo isnt of my engine bay but that is the same part as mine
well i just took it apart to see what the deal is, and it is 100% the AFM. here is a video of the sound, i cant tell if the noise is from air slipping past the metal flap or what. when you push the flap back the noise stops but too much air goes in and the engine stops.
http://s12.photobucket.com/user/movi...96dfe.mp4.html
it has some upgrades and i am trying to get a handle of what i'm dealing with.
the biggest issue at the moment is an annoying sound coming from the "cold air" Downey intake.
at first i thought is was a belt slipping but it is too consistant of a noise.
yesterday i took the top off the dewey air box and the sound is definitely coming from the silver box (AFM?) show in the photo. the photo isnt of my engine bay but that is the same part as mine
well i just took it apart to see what the deal is, and it is 100% the AFM. here is a video of the sound, i cant tell if the noise is from air slipping past the metal flap or what. when you push the flap back the noise stops but too much air goes in and the engine stops.
http://s12.photobucket.com/user/movi...96dfe.mp4.html
Last edited by mattesonb; 07-17-2013 at 11:09 PM.
07-17-2013, 09:26 PM
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The hose in immediately below your arrow is probably the cause. All sorts of noises can come from that hose. It connects from there to your EGR valve and has been described as making all kinds of weird noises...
The silver section has just a flapper in it so shouldn't be grinding. You can remove the top section to which the silver part is attached and manually check that flapper for grinding. I suppose something within that balck cap on top of the circle could be grinding (perhaps the spring failed?) but it'd be unlikely I'd think. Haven't seen it before on here...
The silver section has just a flapper in it so shouldn't be grinding. You can remove the top section to which the silver part is attached and manually check that flapper for grinding. I suppose something within that balck cap on top of the circle could be grinding (perhaps the spring failed?) but it'd be unlikely I'd think. Haven't seen it before on here...
07-17-2013, 11:02 PM
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The hose in immediately below your arrow is probably the cause. All sorts of noises can come from that hose. It connects from there to your EGR valve and has been described as making all kinds of weird noises...
The silver section has just a flapper in it so shouldn't be grinding. You can remove the top section to which the silver part is attached and manually check that flapper for grinding. I suppose something within that balck cap on top of the circle could be grinding (perhaps the spring failed?) but it'd be unlikely I'd think. Haven't seen it before on here...
The silver section has just a flapper in it so shouldn't be grinding. You can remove the top section to which the silver part is attached and manually check that flapper for grinding. I suppose something within that balck cap on top of the circle could be grinding (perhaps the spring failed?) but it'd be unlikely I'd think. Haven't seen it before on here...
well i just took it apart to see what the deal is, and it is 100% the AFM. here is a video of the sound, i cant tell if the noise is from air slipping past the metal flap or what. when you push the flap back the noise stops but too much air goes in and the engine stops.
http://s12.photobucket.com/user/movi...96dfe.mp4.html
Last edited by mattesonb; 07-17-2013 at 11:09 PM.
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03-14-2015, 07:13 PM
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It sounds like its running too lean causing the engine "pinging" noise.
You either have a bad VAFM or it may need to be regulated... Get a sharp knife and cut out the black square cover on the side of the VAFM and there will be a way to regulate it inside, I believe counterclock wise will enrich so you want to go clock wise.
Just as a note: I have not done this, this is what I WILL do once I change over to the 7mge VAFM.
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