Fuel door ?

[Darnon]

In Maine we take care of any thefts ( gasoline or others) in our own way. Everyone knows everyone, at least in our small towns. Except our big city of Portland. 140,00O people. Way Too big to know each other. I would never live there.
Mavericks are beginning to show up. I saw one like mine yesterday!

Yes, yes, we've all heard that dumb country song. You fantasize about shooting looters, got it.

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[GPSMan]

And then "literally" there's no such thing as vacuum. Just higher and lower pressure.

 

[RichardCranium]

How do you define "high vacuum pressure"??

You nor car parts.com have defined this.

Some people believe high vacuum pressure to be negative 14 psi ( high being far from neutral ). Some define high as barely any ( high pressure absolute, close to neutral).

I think you are getting hung up on the word "vacuum". Yes, If I turn on a fan, the inlet side of the fan will have slightly lower pressure than the outlet side. Normal people in normal conversation don't call this "vacuum pressure".

In the gasoline tank, gasoline is going to make it's own +5psi to + 15psi from its own vapor pressure depending on blend and temperature.

In the quote you gave, the "vacuum" can be a simple matter of lowering the natural vapor pressure 1 or 2. It does not mean it is dipping below ambient. It's all relative.

Thanks for admitting I am right. Some cars use vacuum to test for evap leaks.
That is what the conversation is, not to what degree do I define a vacuum.

 

[Darnon]

In the gasoline tank, gasoline is going to make it's own +5psi to + 15psi from its own vapor pressure depending on blend and temperature.

In the quote you gave, the "vacuum" can be a simple matter of lowering the natural vapor pressure 1 or 2. It does not mean it is dipping below ambient. It's all relative.

Most vehicles do test the evap/fuel tank for leaks by reducing pressure below ambient (often by using engine vacuum, as mentioned). Waiting for the fuel to naturally increase the pressure would take too long and require calculating/assuming extra variables to make for a good on demand test.

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