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Discussion Starter #1
Hey guys,

Not really sure if I'm using the right name here, but the air filter unit seems to pop off about once a month on my car. Usually this happens when I've stopped the car and started it again. Once it pops off, it doesn't start again until I put it back on.

Has anyone heard of this happening with a 1984 GTV-6?

Thanks,

Carlos
 

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But Mad North-Northwest
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11,296 Posts
The big silver airbox in the center of the engine? That's not the air filter, that's the intake plenum. Your car is backfiring through the intake and blowing off the plenum.

This'll happen if you put your foot on the gas when starting. If you're not doing that, it's probably an air leak somewhere or a misadjusted throttle position switch.
 

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Or do you mean the connection at the air duct to the Air Flow Meter (AFM) attached to the air filter housing? The filter housing/AFM is fixed to the inner fender while the engine is mounted on rubber blocks. Torque reaction can twist the engine in its mounts and pull the air duct off the AFM.

If this is the problem, check the engine mounts as failing engine mounts will let the engine move too far - taking off in first gear tends to cause the most movement as the engine twists hard to get the car moving (body at rest tending to stay at rest, etc). The air duct is supposed to allow for engine movement - thus the 'accordian' shaped section near the AFM connection. But as the rubber air duct ages the rubber becomes less pliable/elastic and can thus be yanked off even if the engine mounts are good.

I usually have to loosen the air filter cover's snaps, fully seat the AFM into the air duct, tighten its clamp then put the air filter cover back in place.
 

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Discussion Starter #4
Thanks for not making me feel too dumb guys...haha. This is actually my fathers car and I was posting for him. He thought the big thing on the top of the engine was the air filter. Understandable, some classics are like that.

Anyways, GHNL, thanks for trying to make it seems like I knew what I was talking about. But I believe GUBI hit the nail on the head. He is probably talking about that big silver thing about the engine.

I'll let him know your thoughts and see what he can find out from there. Thanks guys.
 

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OK, IMO the dumb questions are the ones you don't ask.

The silver item on top of the engine is the intake plenum (chamber). Air enters and is divided to each intake runner.

The best advice is to never touch the gas pedal when starting the engine. Doing so increases the possibility of an intake back fire which then pops the the intake plenum off the engine.
 
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