Possible Vacuum Problem - Need Help !
Thread Starter
Safety Car
Joined: Jul 2004
Posts: 4,806
Likes: 70
From: Rochester MN
Possible Vacuum Problem - Need Help !
I am posting this for my brother with a 1969 427/425 HP with a new single Edlebrock Q-Jet Carb.
After driving car 10-15 minutes, the headlights come up and stay up until the car is shut off. After it cools down, the lights go down. The process repeats itself. The wiper door will not open once the lights go up. The wiper door works fine at startup. All vacuum lines are new, as is 1 headlight accuator, wiper accuator, and head light switch. No problems seen with lines. The motor is a recent rebuild earlier this year and this problem ONLY started after 500 miles of run time. Motor has a high duiration cam with 1.7 rockers.
What could cause this ? Thanks Dave from C5 forum.
After driving car 10-15 minutes, the headlights come up and stay up until the car is shut off. After it cools down, the lights go down. The process repeats itself. The wiper door will not open once the lights go up. The wiper door works fine at startup. All vacuum lines are new, as is 1 headlight accuator, wiper accuator, and head light switch. No problems seen with lines. The motor is a recent rebuild earlier this year and this problem ONLY started after 500 miles of run time. Motor has a high duiration cam with 1.7 rockers.
What could cause this ? Thanks Dave from C5 forum.
Drifting
Joined: Aug 2002
Posts: 1,731
Likes: 22
From: Marietta Ga.
I would check the check valve, it's the one with one conection to carb and two conections beyond. When they fail, they let the vacuum tank empty, since failsafe for lights is up, they come up when vacuum is lost.
Here's a FAQ site
http://vetteworks.tripod.com/techdocuments/Vaccum.html
also many past threads if you do a search.
Good luck.
PS: her's another site
http://www.corvette-101.com/
Here's a FAQ site
http://vetteworks.tripod.com/techdocuments/Vaccum.html
also many past threads if you do a search.
Good luck.
PS: her's another site
http://www.corvette-101.com/
Last edited by 72GACRZR; Jun 3, 2005 at 04:08 PM.
Thread Starter
Safety Car
Joined: Jul 2004
Posts: 4,806
Likes: 70
From: Rochester MN
Originally Posted by 72GACRZR
I would check the check valve, it's the one with one conection to carb and two conections beyond. When they fail, they let the vacuum tank empty, since failsafe for lights is up, they come up when vacuum is lost.
Here's a FAQ site
http://vetteworks.tripod.com/techdocuments/Vaccum.html
also many past threads if you do a search.
Good luck.
PS: her's another site
http://www.corvette-101.com/
Here's a FAQ site
http://vetteworks.tripod.com/techdocuments/Vaccum.html
also many past threads if you do a search.
Good luck.
PS: her's another site
http://www.corvette-101.com/
I will do a search here as well
Does anyone else have any ideas?
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Someone posted a PDF file here a few weeks ago and it is great to use. Hopefully someone will post the link to the file.
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
http://forums.corvetteforum.com/show...9&forum_id=119
Try this thread and download the PDF. It is really helpful.
Try this thread and download the PDF. It is really helpful.
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