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Vacuum leak causing miss in engine
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
Vacuum leak causing miss in engine
I installed all new vacuum lines and now developed a bad miss in the engine. The engine ran fine until the new lines were installed but since the car is under restoration the vacuum was not connected to any of the acuators before. The vacuum was just plugged off at the intake. I have no idea if the actuators were leaking before but suspect that one or more of them has a leak , causing the leak. I can't listen for a leak since the car has side pipes with that head rattling noise. Any suggestions ? Everything is connected right. Can anyone recommend a good gauge which will show if it is holding a solid vacuum ?
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I had a hard time finding a vacuum leak once, and I used brake cleaner to find it. I connected everything the way it was supposed to be, and I sprayed brake cleaner at all the connected ends of the vacuum lines and accessories. I sprayed the relays where the vacuum tubes connect, same for the witch hat of the actuators. I sprayed the sides and base of the carb, basically everything. I waited after each spray for a rise in engine RPM.
I finally sprayed the vacuum line that connects to the transmission, and the RPMs jumped. I checked, and sure enough the end was corroded and cracked, and it was leaking. I replaced the tube, and all was well again.
I'm not saying that method will find your problem, but it might help.
I finally sprayed the vacuum line that connects to the transmission, and the RPMs jumped. I checked, and sure enough the end was corroded and cracked, and it was leaking. I replaced the tube, and all was well again.
I'm not saying that method will find your problem, but it might help.
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
Just pulled the spark plugs and saw that they are all fouled with gasoline already , so I will have to replace them before i can even continue. I just blocked of the vacuum at the intake again until i'm sure i have the engine running right again, then i will try some of these suggestions but does anyone know of a gauge that would put a vacuum on the system and then show if it is holding it steady without the needle dropping ?
Racer
Joined: Mar 2006
Posts: 454
Likes: 0
From: SAN CLEMENTE CALIFORNIA
Just pulled the spark plugs and saw that they are all fouled with gasoline already , so I will have to replace them before i can even continue. I just blocked of the vacuum at the intake again until i'm sure i have the engine running right again, then i will try some of these suggestions but does anyone know of a gauge that would put a vacuum on the system and then show if it is holding it steady without the needle dropping ?
Plugging off one line at a time is the best way.
but a vaccume leak should make your eng run faster
Team Owner
Joined: Jun 2001
Posts: 23,375
Likes: 1,067
From: Virginia USA
Just pulled the spark plugs and saw that they are all fouled with gasoline already , so I will have to replace them before i can even continue. I just blocked of the vacuum at the intake again until i'm sure i have the engine running right again, then i will try some of these suggestions but does anyone know of a gauge that would put a vacuum on the system and then show if it is holding it steady without the needle dropping ?
http://www.mityvac.com/
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Thread Starter
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
MityVac Can be found in just about any good autoparts store. I think even Sears carries them.
http://www.mityvac.com/
http://www.mityvac.com/
