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intermitent vacuum leak driving me crazy
https://slantsix.org/forum/viewtopic.php?t=11668		 Page 1 of 1
Author:  argentina-slantsixer [ Mon Feb 07, 2005 10:49 pm ]
Post subject:  intermitent vacuum leak driving me crazy
Here's the situation: I have a light vacuumeter on my fender. If you stomp on it, the manifold vac drops so it lites. Is connected on the same hose that power brakes. I drove my car near 300 miles and she was fine, powerful, nice. Then, acouple of days ago, after leaving her sittin for 3 hours in a cold damp place (perry como wasn't there :lol: ) it started to hesitate when part throttleing it. It went away as the car was heating up, so I figured that maybe a li'l condensation was to blame. Replaced air filter element, sprayed the carb passages with carb cleaner, etc. . As the days went on, sometimes I have my vac light on even with engine idling (never before) and this is consistent with several issues I've been havin: the car has some sort of unstability now and then. Today I was returning home, cruisin at 75 give or take, and when I stopped for gas up, when I restarted the engine the low vac light stayed on for a while. I'll check for valvle lash issues, carb gaskets, maifold, etrc. Could a broken or perforated brake booster diaphragm give me this kinda trouble? brake sys is the only thing that I left out in all the work I've donw to this car since I own it. To tell the truth, brakes has been somewhat neglected.
I'll check my spark plugs to see if I can find any symptom of lean mixture... I also have been having temp issues, but not everyday, so maybe when the intermiten vacuum leak kicks in my motor likes to heat up...
thanks in advance, waiting to listen to your input.
Author:  sandy in BC [ Tue Feb 08, 2005 8:10 am ]
Post subject: 
Do you have vacumn operated heater controls?
Author:  SlantSixDan [ Tue Feb 08, 2005 1:09 pm ]
Post subject: 
Yes, a bad booster diaphragm could cause a leak large enough to turn on the Fuel Pacer light, but take a close look at the brake booster vacuum check valve. It's usually right at the booster end of the large-diameter booster vacuum line, but some setups have it more towards the middle of the line.
Author:  argentina-slantsixer [ Wed Feb 09, 2005 2:39 am ]
Post subject: 
No, I don't have vac operated heater controls (lucky me, that sounds more like a pain in the a s s)

Dan: you're referring to the plastic thingy that connects the large vac line to the booster? I didn't know that this li'l fellow has a checkball. I'll check that. tnx.
Author:  SlantSixDan [ Wed Feb 09, 2005 12:20 pm ]
Post subject: 
Quote:
Dan: you're referring to the plastic thingy that connects the large vac line to the booster? I didn't know that this li'l fellow has a checkball. I'll check that. tnx.
Yep, that's the item.
Author:  Mark [ Wed Feb 09, 2005 8:08 pm ]
Post subject: 
One other thing to check/replace is the PCV valve. They get old and dirty inside they start sticking. Just one more thing to look at. If they stick open that will sure cause a vacuum leak.
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