L83 Intake Vents - Won't Shut
Thread Starter
Pro
Joined: Mar 2024
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From: Northern California
L83 Intake Vents - Won't Shut
I have entered the leagues of Corvette ownership by purchasing a 1984 Corvette with the L83 engine inside of it. The engine is equipped with the Crossfire Injection system, and thus it has the two vacuum vents that allow air into the engine.
My problem today is that the right-hand vent will not close. From my research, I know that the right-hand vent is supposed to always stay shut unless the engine is throttled, and then it will open to allow more air into the engine. Currently, the vent just stays open, no matter if the car is off or running. The left-hand vent is operating normally. On startup, it is shut closed and then progressively opens as the engine heats up.
Is there any way to diagnose or fix what's wrong with the right-hand engine vent? Could it be a vacuum leak? Possible electrical failure somewhere? I want to make sure this engine is running "as intended" so this is a decent concern for me. I've searched the forums and have yet to discover anything relating to the right-vent only. There is a wealth of knowledge on the injection system as a whole, and I find myself really liking how GM went about it, even if it is looked back on with shame.
Thank you.
My problem today is that the right-hand vent will not close. From my research, I know that the right-hand vent is supposed to always stay shut unless the engine is throttled, and then it will open to allow more air into the engine. Currently, the vent just stays open, no matter if the car is off or running. The left-hand vent is operating normally. On startup, it is shut closed and then progressively opens as the engine heats up.
Is there any way to diagnose or fix what's wrong with the right-hand engine vent? Could it be a vacuum leak? Possible electrical failure somewhere? I want to make sure this engine is running "as intended" so this is a decent concern for me. I've searched the forums and have yet to discover anything relating to the right-vent only. There is a wealth of knowledge on the injection system as a whole, and I find myself really liking how GM went about it, even if it is looked back on with shame.
Thank you.
Le Mans Master
Joined: Aug 2017
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From: New Jersey
1 vacuum line comes off the rear throttle body to a tee. Then goes to the vacuum diaphragm on the passenger side, or to the thermac for the driver side. By pulling vacuum on the hose you can test both sides. Doesn't take all that much. Inspect the hoses as well.
Safety Car
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Thread Starter
Pro
Joined: Mar 2024
Posts: 537
Likes: 379
From: Northern California
Thank you for the tip, I'll give it a shot once I'm back in town. I hear the vacuum system on the L83 engine is critical so I will go through and see what's what in terms of fixing it properly.
Thread Starter
Pro
Joined: Mar 2024
Posts: 537
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From: Northern California
I had the genius idea to just gently nudge the right door closed with my finger. It worked, the door gently shut and stayed closed all on it's own. This was until the engine warmed up, and now both left and right were open.
I may be facing the idea of buying a new vacuum actuator for the right door. I will keep running tests and seeing what is going on with it. But hey, at least she runs. That's what I can be happy about!
