Topic: Headlights up down with engine off?
in Forum: C3 General Discussion
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[QUOTE=kenimpzoom]...OK, this begs the question. If the vacuum reseviour doesnt hold enought vacuum after the engine is off, does that mean there is a vacuum leak somewhere?...[/QUOTE]
6880Mike 2008-04-02 05:40:06
Yes. You have a vacuum leak. All C3s have a vacuum reserve to cycle headlights/wiper door a time or two with the engine off. Older cars have the reserve tank on the rear of the left fender skirt; others use the front crossmember; and later cars have a coffee can arrangement. Regardless of the set up, it stores vacuum.
If the system is not holding a modicum of vacuum, there is likely to be a leak.
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Hey Joel, do you have to regualte the vacuum pump, or can you just run it wide open to check all the systems?
[QUOTE=kenimpzoom]
[/QUOTE]
Wont that vacuum leak cause tuning issues with the carb?
All things being equal, a bad check valve may not actually appear to be a "leak" to the engine side. But a bad check valve will allow the vacuum to rapidly bleed off back through the intake when the engine shuts down.
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My backyard method is to let the car idle, then spray all over with starting fluid. If the engine speeds up, you hit a leak. Be careful not to hit the exhaust manifolds!
The system should hold vacuum for at least five minutes if it is healthy.
Larry
The system should hold vacuum for at least five minutes if it is healthy.
Larry
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They should not close. Isn't there a valve under the steering column under the dash to let the vacumn leak off to close the lights when the engine is off? jbs82vette 2008-04-02 10:00:51
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[QUOTE=MikeMc71]Hey Joel, do you have to regualte the vacuum pump, or can you just run it wide open to check all the systems?
[/QUOTE]
The pump will only pull around 40 inches or so, but I just let it run. Most systems have enough leaks it ain't an issue anyway.
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[QUOTE=Adams' Apple] [QUOTE=MikeMc71]Hey Joel, do you have to regualte the vacuum pump, or can you just run it wide open to check all the systems?
[/QUOTE]
The pump will only pull around 40 inches or so, but I just let it run. Most systems have enough leaks it ain't an issue anyway.[/QUOTE]
The pump will only pull around 40 inches or so, but I just let it run. Most systems have enough leaks it ain't an issue anyway.
[/QUOTE]
LOL.....good point! 
I know I have a slight problem because when I have the lights off and I turn off the engine, the passenger side light will sometimes pop up by itself.
I turn the engine back on, the light goes down.
Very strange to watch.
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