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Aeration

Jobless said:
How hot does gasoline have to get before aeration occurs?

This is in a pressurized EFI system running about 36psi.
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As in vapor locking? Im sure the higher fuel press requires more heat to vapor it. Im curious now since my fuel system is a bit close to the exhaust...
 
The problem is that gasoline isn't a homogeneous compound. It's got a bunch of different alkenes and alkanes and various hydrocarbons all mixed together. Each one of those different compounds has a diffferent vapor pressure. Some will volatilize at cooler temps, and others at higher temps.

No matter how cold it is (in real world situations), some of the liquid will become vapor, so there's no defined point where it 'happens'. It's just that, the warmer it is, the faster it happens. Keeping the system under pressure helps counter the effect, but I can't tell you how much for sure. 36psi is about 2.5atm (above the ambient atmospheric pressure of ~1), so I'd guess that the fuel under pressure is more resistant to vaporization by a factor of about 3.5 <--- WAGNER.
 
Altitude may play a small part in this too. Liquids boil at different temperatures at different altitudes.
 
Jobless said:
No, not vapor lock.

The point in which the fuel gets hot enough, under pressure, to create vapor in the lines and cause performance issues.
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I'm gonna say 210* on the guage and air temp 'bout 90* seems to send my shitbox into fits:rolleyes: but you already new that:flipoff:
 
Jobless said:
No, not vapor lock.

The point in which the fuel gets hot enough, under pressure, to create vapor in the lines and cause performance issues.
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Vapor lock :flipoff:

I don't know what temp the fuel would have to reach to boil under 36 PSI, but we all know it's quite hot. I would never expect it to happen with the pump circulating fuel. I've only seen it happen after hot shutdown, and then only on a hot day.
 
Ashes said:
Altitude may play a small part in this too. Liquids boil at different temperatures at different altitudes.
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Altitude is negated by a pressurized system, although hot shut down + high altitude + fuel system pressure drop could be a problem.
 
CrustyJeep said:
Vapor lock :flipoff:
I would never expect it to happen with the pump circulating fuel.
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Less common on a circulating system but it still happens. The 5.0 does have a dead headed fuel rail (I checked) which contributes here too. We could probably do some testing with a thermocouple but in the end it just needs to be cooler.
 
Yeah, then I'd be really surprised if vapor is the problem, unless you're getting the classic hot restart problem.
 
Is this happening on your rig brad? Im having issues and am close to going with a e2000 pump.
 
Jobless said:
Huh?

All fuel pumped to the motor is returned to the tank via the pressure regulator and return line, minus of course what is burned.
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Look at your fuel rail. The fuel goes into and out of it on the same spot. There's only like 2 inches that is through circulated. The end injectors are a dead givaway. There is no way the fuel is circulated past them.....
 
I was chatting with Conover today and he felt that the injectors were fubar.I did have probs with them right from the get go and alot of what he cited as examples/symptoms were spot on to what we were dealing with.Maybe it's time for 24# 'jectors and MAF:FIREdevil:
 
Bunk said:
Is this happening on your rig brad? Im having issues and am close to going with a e2000 pump.
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Brad started having issues towards the end of the week but my junk would barely run from the get go:rolleyes: F'in sucked!! so many possible causes to the symptoms presented that trouble shooting was a NIGHTMARE!! Seemed the root of the problem was heat affecting "X" and the whole shiteree took a dump:mad: Way more complex than that but thats the "jist".

Rick and Brad got it runnin good enough to still alow me to destroy some ****:; :FIREdevil:
 
jeepmauler said:
I was chatting with Conover today and he felt that the injectors were fubar.I did have probs with them right from the get go and alot of what he cited as examples/symptoms were spot on to what we were dealing with.Maybe it's time for 24# 'jectors and MAF:FIREdevil:
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Could very well be.....It's definately heat sensitive, maybe your injectors are being effected by heat?<shrug>
If I had all of the answers it would have been running like a top last week......
 


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