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Vacuum Lines Disconnected

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Old Dec 13, 2009 | 10:11 AM
  #1  
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Default Vacuum Lines Disconnected

Hi,

I bought my wife an 81 that has all the original parts in a box, but has a new manifold and carb. After poking around, it appears that there are many vacuum lines (hoses - maybe not all vacuum) that are disconnected and just laying there open ended. Is this a bad thing? How do I figure out what all these are for and which are critical? The car runs well, windshield wipers and lights work. Any suggestions would be appreciated. I want it to be right.

Also, where do I get a diagram of how all this stuff is supposed to be hooked up on the original?

Shiff
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Old Dec 13, 2009 | 10:14 AM
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It would be much easier to help if you post a couple pics.
Here's an AIM on CD that might help.
http://willcoxcorvette.com/product_i...ducts_id=25543

Last edited by ...Roger...; Dec 13, 2009 at 12:06 PM.
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Old Dec 13, 2009 | 10:26 AM
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Purchase the factory service manual; the information will be in there.
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Old Dec 13, 2009 | 10:34 AM
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Default Factory Shop Manual - where to get

Where do I get the factory shop manual? Is it available on CD/DVD?

Shiff
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Old Dec 13, 2009 | 10:39 AM
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Default Shop Manual

Would this be the Shop Manual or is there something else/better?

http://www.ecklers.com/product.asp?p...10&dept_id=226

Shiff
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Old Dec 13, 2009 | 10:46 AM
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Go to abebooks.com and enter 1981 corvette on the key word line.

54. Bookseller Photo 1981 Chevrolet Corvette Shop Manual ST-364-81
No Author Noted
Bookseller: Good Earth Books
(Evansville, IN, U.S.A.)

Bookseller Rating:

Quantity Available: 1
Book Description: Chevrolet Motor Division, Detroit, Michigan, U.S.A., 1980. Trade Paperback. Book Condition: Good Minus. No Jacket. 8 1/2 x 11 inches. This shop manual is sound and tight and 100% readable; interior is surpisingly clean, considering that the exterior is quite soiled; binding shows rubbing and edgewear but is still solid and very firmly attached and not torn. Unpaginated, but 1 1/4" thick and printed on thin but sturdy stock and profusely illustrated. "This manual contains procedures for diagnosis, maintenance adjustments, minor service operations, replacement of components (Service) and for disassembly and assembly of major components (Unit Repair-Overhaul).". Bookseller Inventory # 012764

Bookseller & Payment Information | More Books from this Seller | Ask Bookseller a Question

Price: US$ 60.00

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Shipping: US$ 3.95

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Old Dec 13, 2009 | 10:59 AM
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Thanks

Shiff
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Old Dec 13, 2009 | 11:47 AM
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In answer to your original question.... Yes, having vacuum lines loose/open is a bad thing, particularly if the other end is still connected to the intake manifold and/or carb. Vacuum leaks are a major source of idle and performance problems. In addition, not being connected means that they are not providing signal to the devices which they were intended to operate...ie, EGR valve, distributor vacuum can, etc, etc. Study the vacuum system design and the function of the devices connected to it. Then decide which ones you need to keep, which ones you want to keep, and which you can discard without negative impact to the vehicle.
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Old Dec 13, 2009 | 01:13 PM
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Originally Posted by pshiffer
Hi,

I bought my wife an 81 that has all the original parts in a box, but has a new manifold and carb. After poking around, it appears that there are many vacuum lines (hoses - maybe not all vacuum) that are disconnected and just laying there open ended. Is this a bad thing? How do I figure out what all these are for and which are critical? The car runs well, windshield wipers and lights work. Any suggestions would be appreciated. I want it to be right.

Also, where do I get a diagram of how all this stuff is supposed to be hooked up on the original?

Shiff
I would suspect that since the carb and intake and dist. are changed, that the computer has been disconnected. Does it still have the EPA stuff installed, smog pump etc..? If not there are an aweful lot of vacuum lines going to the smog stuff. If it is running good, check and see if these lines are coming from the engine or merely dissconnected from a no longer needed item that required a vacuum source that you can remove and clean things up, dont panic. Let us know what you find.
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Old Dec 13, 2009 | 07:25 PM
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Yes Sir: Chevrolet Motor Division Has Helm produce their Chevrolet Corvette Shop Manual for them, !-800-782-4356 They will take your order over the phone. Have a great day. Gene
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Old Dec 14, 2009 | 12:33 PM
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Bidding on the manual on Ebay - I will let you know when I have a chance to look it over and dig under the hood - probabaly between Christmas and New Years. Thanks all for the help.
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Old Dec 24, 2009 | 11:22 AM
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The lines that are disconnected appear to only be relevant to a cold start EGR 'feature' to keep emissions down when the engine is cold. Not mission critical, but I will probably hook them up again. The Vacuum chart has different colors and lines with stripes. What is the difference between the lines - there is no color code or legend on the diagram in the car or in the book?
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Old Dec 24, 2009 | 01:12 PM
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Hello,
put some picture of your engine bay,in this way is to easy help you.
If you can drive the car with out all the stauff for smog(legal for your contry) remove it.
I have an '81 too and I have removed and the engine bay appear too clean.
Merry X-Mas
Giuseppe
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Old Dec 24, 2009 | 01:55 PM
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I agree, souds like computer system has been defeated. Thats a good thing it will be less problems down the road. I just did that on my '81, it the best thing I ever did to it.
You just need to find out what the lines were for and reconnect or remove if its somthing for the emissions. If you need to pass emission test a '81 without computer. etc.. will pass as long as you have a converter and proper tuning. Pictures on here will help us help you. Congrats and Good luck
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