Vacuum problem
Thread Starter
Navigator
Joined: Mar 2012
Posts: 9
Likes: 0
Vacuum problem
Having trouble pulling vacuum to open head light doors. Was told the motor has to big of a cam to pull vacuum. Can an auxiliary pump be added to correct this? If so any idea where to get one? Thanks for any help.
Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
make sure you dont have a leak somewhere in the lines or vacuum tank. and relays and actuators are not leaking throught the seals. there is also a bypass switch for the headlights at the base of the steering column, try that also, as you headlight switch may be malfunctioning,. summitracing sells several different styles though
http://www.summitracing.com/parts/SSB-28146/
http://www.summitracing.com/parts/SSB-28146/
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
What size cam does the engine have? Sometimes low vacuum can be due to bad tuning. Get your hands on a vacuum gauge and see what the vacuum is at idle. Adjust the idle screws for highest vacuum, and reset idle speed, if needed.
In my experience, people who say things like "The cam is too big to pull vacuum." usually just say that because they are too lazy or aren't knowledgeable enough to fix what's wrong. You don't need a whole lot of vacuum to pull the headlight doors, (if there are no leaks in the system) the vacuum isn't what pulls them up, it's just a signal, the difference between atmospheric pressure and the vacuum is what makes the doors move. Kinda like a siphon........sort of. If you have power brakes, and the power brakes work just fine, I don't think there is any reason the headlight doors shouldn't work just fine, too. Here is a link to a very good thread that does an excellent job of explaining how your vacuum system works, and how to work with it.
http://forums.corvetteforum.com/c3-t...tem-works.html
Keep the shiny side up!
Scott
In my experience, people who say things like "The cam is too big to pull vacuum." usually just say that because they are too lazy or aren't knowledgeable enough to fix what's wrong. You don't need a whole lot of vacuum to pull the headlight doors, (if there are no leaks in the system) the vacuum isn't what pulls them up, it's just a signal, the difference between atmospheric pressure and the vacuum is what makes the doors move. Kinda like a siphon........sort of. If you have power brakes, and the power brakes work just fine, I don't think there is any reason the headlight doors shouldn't work just fine, too. Here is a link to a very good thread that does an excellent job of explaining how your vacuum system works, and how to work with it.
http://forums.corvetteforum.com/c3-t...tem-works.html
Keep the shiny side up!
Scott
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
A worn-out headlight vacuum relay can cause the same effect. If it's only the cam, just raise the rpm in idle to 2000 rpm and you'll have plenty of vacuum to operate the headlights. If it still doesn't work well, replace the vacuum relay.
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