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Vacuum leak on BBK intake

This is a discussion on Vacuum leak on BBK intake within the Firebird / WS6 forums, part of the Vehicle Specific category; I installed a BBK intake on my 00transam about two months ago and it ran great for the first month ...

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    Vacuum leak on BBK intake

    I installed a BBK intake on my 00transam about two months ago and it ran great for the first month and a half. After it started stuttering on take offs and at low rpm our scanner showed lean misfires. Smoke tested and using horoscope found intake gaskets leaking. Since then have found had intake off and on 3-4 times trying to fix problem and finding out a lot that BBK did not tell me about clearances for install. I finally believe everything is clear but still vacuum leak. Could the clearance issues have warped this intake or is this a problem with them??? Thinking of telling bbk to send me a replacement. Any help appreciated.

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    Spaz is My Mentor SMWS6TA's Avatar
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    Navy Blue Metallic
    98 T/A w/a little mods...

    I've heard nothing but issues with that intake. There are some that have made it work. Talk with 88gtman. He has one. I'll see if I can get him to respond to you.

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    Cool appreciate it!!!!

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    Spaz is My Mentor SMWS6TA's Avatar
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    Navy Blue Metallic
    98 T/A w/a little mods...

    Scott asks, Have you replaced the valley cover tray bolts or still using stock?


    9/10 it's usually that. Need a button head style bolt.

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    Yep replaced the bolt at the rear with button bolt....thanks for the response

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    Member 88gtman's Avatar
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    Ok. Couple things to check.
    #1 make sure the screws holding the blowout plate on are not loose. I also highly recommend putting some blue loctite on each of them. Also make sure the gasket on the blowout plate is in good shape and sealing well.

    #2 The TB gasket BBK supplies with their intake does not have the hole in it for the IAC. This prevents the air that bypasses the IAC to get into the intake. Simply cut out a hole for it in the gasket.

    #3 Make sure you torque down the intake in the proper sequence using a torque wrench. I know BBK's instructions simply say to tighten them until the washers crush, but later I found them to be too loose. Torque them to 44in/lbs the first pass, then torque them to 89in/lbs the second pass.

    #4 If you still have a vacuum problem you can spray some carb cleaner around the intake manifold and on the vacuum lines while the engine is running and if the rpm's suddenly drop then that is where your leak is.

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    We used a smoke machine and boroscope and could actually see it coming out of intake gaskets near the bottom. We plugged the intake on a bench and smoked it. No smoke from the blowoff pan.

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    Member 88gtman's Avatar
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    Does it feel like the intake is sitting flat when you set the intake down? If so, how old and which gaskets did you use? When I installed mine I used brand new felpro gaskets when I did mine. I have 3 yrs and about 25k miles on my BBK intake and never had a problem.

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    BBK intake leaks

    Quote Originally Posted by 88gtman View Post
    Does it feel like the intake is sitting flat when you set the intake down? If so, how old and which gaskets did you use? When I installed mine I used brand new felpro gaskets when I did mine. I have 3 yrs and about 25k miles on my BBK intake and never had a problem.
    The first time we put it down 2 months ago it didn't feel good so we called bbk and they said there was no interference issues. We looked and didn't see anything so we put it together(new felpro gaskets of course). Ran great for a month and a half then started stuttering on normal takeoff and driving under low rpm. Scanner showed lean misfires. Smoke machine and boroscope showed intake gaskets. Since then its been off and on multiple times eliminating interferences as we found them. It sits level but still leaks at bottom of intake gaskets. Honestly bbk has been very unhelpful even during the buying process. Am now at the point of having them warranty it and trying another intake of theirs. Thanks for you suggestions.

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    Have you checked the intake's mounting surfaces for flatness with a steel rule or something similar?

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    Yes and we didn't notice any warpage. I found someone on another site with the same problem that happened a month or so after he installed the intake, he never found an answer and ended up getting a ls6 manifold. Thank you for your help.

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    LS6 intake is a good choice.
    SMWS6TA likes this.

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    Yep, I'd put an LS6 on there and be done with it. At the first hint of trouble I'd have yanked that puppy.
    For all the money, time, and headache you've put up with you would have been money ahead already.
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