How much vacuum?
Thread Starter
Racer
Joined: May 2007
Posts: 370
Likes: 0
From: Cherry Hill N.J.
How much vacuum?
Hi everyone;
I have been having a problem with a rough running engine(77 L48).
Prior to my current problem the engine was running great.
After driving for about 10 miles the engine started to stumble. When I stopped for traffic lights it almost stalled.
I have checked plugs, wires ,timing,valves, distributor & rotor with no apparent problem.......However when checking vacuum I found it to be between 10-12 range....In the past it was usually around 18-20 range and steady.
What could cause the lower vacuum and could this be my problem with my miss and stumble in the engine.
Thanks for your answers in advance.
I have been having a problem with a rough running engine(77 L48).
Prior to my current problem the engine was running great.
After driving for about 10 miles the engine started to stumble. When I stopped for traffic lights it almost stalled.
I have checked plugs, wires ,timing,valves, distributor & rotor with no apparent problem.......However when checking vacuum I found it to be between 10-12 range....In the past it was usually around 18-20 range and steady.
What could cause the lower vacuum and could this be my problem with my miss and stumble in the engine.
Thanks for your answers in advance.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Hi everyone;
I have been having a problem with a rough running engine(77 L48).
Prior to my current problem the engine was running great.
After driving for about 10 miles the engine started to stumble. When I stopped for traffic lights it almost stalled.
I have checked plugs, wires ,timing,valves, distributor & rotor with no apparent problem.......However when checking vacuum I found it to be between 10-12 range....In the past it was usually around 18-20 range and steady.
What could cause the lower vacuum and could this be my problem with my miss and stumble in the engine.
Thanks for your answers in advance.
I have been having a problem with a rough running engine(77 L48).
Prior to my current problem the engine was running great.
After driving for about 10 miles the engine started to stumble. When I stopped for traffic lights it almost stalled.
I have checked plugs, wires ,timing,valves, distributor & rotor with no apparent problem.......However when checking vacuum I found it to be between 10-12 range....In the past it was usually around 18-20 range and steady.
What could cause the lower vacuum and could this be my problem with my miss and stumble in the engine.
Thanks for your answers in advance.
You probably just have a vacuum leak somewhere. Cap all the ports not needed for engine operation, and see if that helps. The start uncapping them and plugging in that line one by one to see where things start to go bad. This will help you narrow the leak down to a specific system like headlights or transmission or HVAC.
Instructor
Joined: Mar 2008
Posts: 173
Likes: 1
From: New york New york
Sorry, But the same thing happened to me last feb. It ended up being an intake manifold leak. I changed both intake & carb. and problem solved.
P.S. the carb did not need to be changed but I figured what the heck
P.S. the carb did not need to be changed but I figured what the heck
Melting Slicks
Joined: Apr 2001
Posts: 2,030
Likes: 363
From: Lubbock Texas
DC
Thread Starter
Racer
Joined: May 2007
Posts: 370
Likes: 0
From: Cherry Hill N.J.
How much vacuum?
Today I checked vacuum again and not only was it lower the needle fluctuated back and fourth and was not steady..
Adjusting timing had little effect.......could I have a timing chain problem or what else could cause my problem?
Adjusting timing had little effect.......could I have a timing chain problem or what else could cause my problem?
Melting Slicks
Joined: Apr 2001
Posts: 2,030
Likes: 363
From: Lubbock Texas
Here are a couple of links to sites I found while I was chasing my vacuum issue:
http://www.therangerstation.com/Maga...acuumLeaks.htm
http://www.international-auto.com/fi...uum-gauges.cfm
Hope it helps.
DC
http://www.therangerstation.com/Maga...acuumLeaks.htm
http://www.international-auto.com/fi...uum-gauges.cfm
Hope it helps.
DC
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Joined: Apr 2001
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Likes: 363
From: Lubbock Texas
DC3
