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2000 4.3 intake to injector assembly vacuum leak help!

Old Nov 7, 2024 | 09:12 AM
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Default 2000 4.3 intake to injector assembly vacuum leak help!

please and thank you for all your help!

Ok so I got my dad’s ZR2 completed and running with my new motor I gave him. Brand new everything, AC Delco updated spider injector assembly.

Here’s my issue

So when I goose the throttle where the injector assembly comes thru the upper intake the assembly pushes up into the upper plenum and I can hear a vacuum whistle. I’m sure the movement isn’t supposed to happen so I’ve done no chemical spraying to prove that’s my vacuum leak cause I don’t want a giant mess on my new motor. can anyone give me some tips to get that to stop preferably without pulling the entire upper intake .

Please and Thank you all for the help!!
 
Old Nov 8, 2024 | 07:41 AM
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Buttefly plates often whistle due to air going past the sharp plate edges. Personally I dont recall vacuum leaks causing whistle. A small burst of carb or brake cleaner spray ( petroleum solvents) will show a leak because the spray is combustible- the idle speed should jump. The sprays wont leave residue in small amounts.
 
Old Nov 8, 2024 | 06:50 PM
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Originally Posted by daveca
Buttefly plates often whistle due to air going past the sharp plate edges. Personally I dont recall vacuum leaks causing whistle. A small burst of carb or brake cleaner spray ( petroleum solvents) will show a leak because the spray is combustible- the idle speed should jump. The sprays wont leave residue in small amounts.

the whole electric plug and what the fuel lines connect to go up in the air when you step on the gas removing the engines vacuum. It’s like the vacuum is pulling the part of the injector assembly that goes thru the upper intake.
 
Old Nov 9, 2024 | 09:12 AM
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Sounds like you will have to remover the upper intake and see what is going on. Is the bracket for the spider the correct one? Is the big center seal out of place?
 
Old Nov 9, 2024 | 09:53 PM
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Originally Posted by LesMyer
Sounds like you will have to remover the upper intake and see what is going on. Is the bracket for the spider the correct one? Is the big center seal out of place?

So I believe I have actually determined that it’s the throttle body sucking air. I forgot about it but I did cut off that goofy thing on the throttle body butterfly.
 
Old Nov 10, 2024 | 10:58 AM
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Default Ok updated injectors! Didn’t change mounting bracket?

Ok so I do have the updated injectors, and I just found a link below my post for this issue. Maybe I’m wrong and I do have a problem at my injector block that goes thru intake.
 
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