vacuum lines diagram

[blackjack]

hi,all
i need some sort of diagram for the vacuum lines under the plenum...problem is i have two hoses going into the secondary port throttle valve solenoid at one end,and an open fitting at the other end,with no hose attached to it...the car is whistling at idle,so i figured this is the problem...what goes on there? the shop manual is not clear about this...any idea?:confused:
bj

[tccrab]

Everytghing you ever needed to know about the Secondary Vacuum system and more:
http://www.corvetteactioncenter.com/forums/showthread.php?t=14272
A picture is worth a thousand words:
http://i4.photobucket.com/albums/y114/LoTu5/2005_1217vac70001.jpg
Tom

[Jeffvette]

The open end should have a conical filter on it.

[blackjack]

right,jeff...looks like im missing the air filter...ill order it tomorrow...hope the general still has it in stock
thanks
bj

[TNorthcott]

Hello, I just joined a few days ago and already have a question I hope one of you can answer. I have a 1990 Lingenfelter and am in need of replacing the 2 port vacuum diaphram that is located on the plenum up front on the driver's side. I am not sure what it is called but it appears that one of the lines go to the vacuum reservoir. If I am not clear I can attach a picture tomorrow.

Thanks for any help you can provide.

[Jeffvette]

This thing?


http://www.pnwzr1.net/Jeff/IMG_4926.JPG

[TNorthcott]

That is exactly what I am talking about; your good. Do you have a part number and/or know where I can get one? My rubber is all stretched out and is very loose.

[tccrab]

That is exactly what I am talking about; your good. Do you have a part number and/or know where I can get one? My rubber is all stretched out and is very loose.

The bad news is that part is NLA from GM.
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The good news is that you can buy one from Jeffvette. :wink:
It's a little early here on the Left Coast, but send Jeffie a PM and he'll fix you up.
I replaced mine last summer and let me tell you, it's a PITA to get it in the right place and getting it to seal correctly. Be prepared to spend some time getting it *just right*. One hole is slightly smaller than the other, the plastic line goes in the hole that is smaller. Otherwise it'll never seal... (don't ask me how long it took me to figure out that little gem..):rolleyes:

[TNorthcott]

That would explain the silicone around the holes, apparently the guy before me had an issue with getting it to seal as well. Thanks for the tip I will give Jeff a posting.

While I am at it, have you heard about a knocking sound coming from the right bank timing chain? I have been told that this is normal on early ZR1s and that a new tensioner will take care of the noise. Does this sound right?

[tccrab]

While I am at it, have you heard about a knocking sound coming from the right bank timing chain? I have been told that this is normal on early ZR1s and that a new tensioner will take care of the noise. Does this sound right?

Noisy chain tensioners on the early Z's are a known issue, see here:
http://www.zr1netregistry.com/ZR1_issues.htm#5

Before I'd replace the CCT, I'd try a different oil filter. You'd be surprised the role that the oil filter plays in causing chain slap on start up. Here's a write-up on Marc Haibec's web site:
http://zr1specialist.com/HAT%20Web/articles/an_lt5_filter_comparison.htm

Good luck!

[TNorthcott]

I will try the new oil filter thanks for the advice. I think my problem may be more serious, it doesn't go away after start up. The noise is there at idle but the instant gas is applied it disappears. I hope it is the tensioners, I really don't want to get into it's guts.