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I have a 1965 with 289, stock carb man fuel pump. The care is running great but will be driving along and you just feel no power in the gas pedel and then car just dies. any idea?? vapor lock?? and if so how can I stop it
Doc
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Vapor lock rarely effects a car that's running. Vapor lock sets in when you shut the car off hot and it won't restart because the fuel in float bowl boils, and creates a gaseous obstruction to fuel flow. When the car is allowed to sit and cool down the fuel condenses back into a liquid and the car can be restarted.
When it dies can it easily be restarted? Do you have to give it fuel to get it to restart (pump the gas pedal, etc.)?
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hello doc , This happens me too but only when i am running hot on trafic stop and go.
You can make a different route of gas pipe coming from pump and stay away from engine ,
or use differnt pipe- not the steel pipe original.
The carb and gas pipe needs to run cooler . everything will cool down , will be good.
But could be everithing ... water in gas , Dirty tank , the sender unit has a filter that can be clogged, dirty carbs, float not working or fuel line filters , carb issue or the gas tank cap has some problem and dont allows air goes to tank.
I think you need to check some point before put the finger.
hope it helps
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TKOPerformance wrote:
Vapor lock rarely effects a car that's running. Vapor lock sets in when you shut the car off hot and it won't restart because the fuel in float bowl boils, and creates a gaseous obstruction to fuel flow. When the car is allowed to sit and cool down the fuel condenses back into a liquid and the car can be restarted.
When it dies can it easily be restarted? Do you have to give it fuel to get it to restart (pump the gas pedal, etc.)?
Allow me to present some alternative facts. The stock cast iron intake maifolds held much more heat than aluminum manifolds. Depending on seasonal fuel mixture the intake can get hot enough to boil the fuel in the fuel bowls of a carb. When the fuel boils, the bubbles can hold the float up against the seat, preventing liquid fuel from flowing in. The boiling fuel lowers the fuel density enough that the engine will no longer run. When the engine stalls, the residual heat in the intake continues to boil the fuel, often boiling the carb fuel bowls dry. The boiling gasoline turns to vapor and exits the carb through the fuel bowl vents (those vertical tubes with the slant cut ends on Hollies). After the gasoline vapor is vented it is nonrecoverable. These vapor vents are the usual source of the “gas stink” carb cars are famous for. After the intake manifold cools down below the boiling point of the fuel it will be possible to refill the carb fuel bowls with the fuel pump. If a restart is tried immediately after a stall, the new gas will boil. If enough gas boils away a residue of heavier hydrocarbons will remain, rather like kerosine or heavier which will not support combustion in a “modern” engine. Might run in a flathead. I knew a guy that would steal “drip” from natural gas well processing stations to run in his flattie.
All of this is why Ford provided phenolic spacers between the cast iron manifold and the carb, to insulate the carb from the manifold.
A fuel injection system is closed so there is no vent and the fuel pressure is high enough to prevent fuel boiling, so no gas stink
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Next time it does it, jump out real fast and open your gas cap, but listen for a giant sucking sound at the same time. Lack of venting in a tank is a real problem for some. Tank either has to be vented or have a vented gas cap. Mustangs have vented gas caps. Some replacements do not function properly.
Just knocking potential problems off the list..
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I actually had a vapor lock issue on a fuel injected car caused by a fuel pressure regulator that would stick shut when it got hot. The fuel in the rails would turn to vapor and had nowhere to go so it stopped new fuel from filling the rails and allowing the engine to start. I finally figured it out by connecting a pressure gauge, watching it skyrocket, then spraying the regulator with Dust Off and the pressure dropped as it cooled and allowed the vapor to exit.
Anything's possible, but I've never had a carbed vehicle stop running due to vapor lock. Possibly the aluminum intake spacer was enough of a heat sink to prevent it on my '67. I certainly had issues with it when the car would not restart though.
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Hornman wrote:
TKOPerformance wrote:
Vapor lock rarely effects a car that's running. Vapor lock sets in when you shut the car off hot and it won't restart because the fuel in float bowl boils, and creates a gaseous obstruction to fuel flow. When the car is allowed to sit and cool down the fuel condenses back into a liquid and the car can be restarted.
When it dies can it easily be restarted? Do you have to give it fuel to get it to restart (pump the gas pedal, etc.)?
Allow me to present some alternative facts. The stock cast iron intake maifolds held much more heat than aluminum manifolds. Depending on seasonal fuel mixture the intake can get hot enough to boil the fuel in the fuel bowls of a carb. When the fuel boils, the bubbles can hold the float up against the seat, preventing liquid fuel from flowing in. The boiling fuel lowers the fuel density enough that the engine will no longer run. When the engine stalls, the residual heat in the intake continues to boil the fuel, often boiling the carb fuel bowls dry. The boiling gasoline turns to vapor and exits the carb through the fuel bowl vents (those vertical tubes with the slant cut ends on Hollies). After the gasoline vapor is vented it is nonrecoverable. These vapor vents are the usual source of the “gas stink” carb cars are famous for. After the intake manifold cools down below the boiling point of the fuel it will be possible to refill the carb fuel bowls with the fuel pump. If a restart is tried immediately after a stall, the new gas will boil. If enough gas boils away a residue of heavier hydrocarbons will remain, rather like kerosine or heavier which will not support combustion in a “modern” engine. Might run in a flathead. I knew a guy that would steal “drip” from natural gas well processing stations to run in his flattie.
All of this is why Ford provided phenolic spacers between the cast iron manifold and the carb, to insulate the carb from the manifold.
A fuel injection system is closed so there is no vent and the fuel pressure is high enough to prevent fuel boiling, so no gas stink
X-2........^^^^^...also insulate the carb.......keep fuel lines away from heat (as-much-as-possible).....remove as much heat as possible from engine compartment.
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had that happen to me and it ended up being the fuel filter was clogged with rust. It would run for a while the die, finally figured it out!
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Triton wrote:
had that happen to me and it ended up being the fuel filter was clogged with rust. It would run for a while the die, finally figured it out!
Sounds more likely to me, and changing a fuel filter takes all of five minutes. With this new "gas", and I use that term loosely, you really have to change fuel filters a lot more often. Not a bad idea to check the float bowl either. Some junk swimming around in there can plug the needle and seat and then you're out of business until it clears.
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