more on vapor lock

Took a trip in the truck today about 45 min ride to pu some tractor parts. Ran real well on the way there but on the way home had some vapor lock problems. Kicked on the electric in line fuel pump seemed to solve it. Ran well for about 1/2 the trip home then started vapor locking again with the electric pump running. Read the vapor lock thread on the archives about using a gallon of diesel fuel and I will try that but why after 2 years of no problems would it start vapor locking again. I put a rubber hose around the line to insulate it a couple of years ago and til now it seemed to help. Any other suggestions besides the diesel? Also does it matter road diesel or off road diesel?
Oh yeah one more unrelated question. I am going to go to SB for the day on Thursday, I have been told that is the best day to go, do I need to do anything to get into to see the cars? Never been to an International meet. Might be a stupid question.

[Chucks Stude]

I have a theory on why you are having vapor lock problems all of a sudden. I have a 2004 f%$^ Truck with a MPG readout on it. The mpg went down about 2 to 3 months ago. I have heard from a weekend car guy on the radio that the amount of alcohol in fuel has been raised. I think that alcohol has such a low boiling point, that it is not helping vapor lock at all. I guess that is why they now run such high pressure fuel systems in modern vehicles.
Also, you might be caught in the transition between winter and summer blend fuel.
Next, I guess we will have to start worrying about carbon buildup, since modern fuel generates a ton of carbon. Lovely

[Chucks Stude]

I have a theory on why you are having vapor lock problems all of a sudden. I have a 2004 f%$^ Truck with a MPG readout on it. The mpg went down about 2 to 3 months ago. I have heard from a weekend car guy on the radio that the amount of alcohol in fuel has been raised. I think that alcohol has such a low boiling point, that it is not helping vapor lock at all. I guess that is why they now run such high pressure fuel systems in modern vehicles.
Also, you might be caught in the transition between winter and summer blend fuel.
Next, I guess we will have to start worrying about carbon buildup, since modern fuel generates a ton of carbon. Lovely

[sntsftbll]

I can buy that alcohol theory since I used BP gas the last two fill ups. It might explain the lifting of my paint from gas runoff also. I have been told that BP contains more alcohol than most. I will try another brand for a while see what happens

[sntsftbll]

I can buy that alcohol theory since I used BP gas the last two fill ups. It might explain the lifting of my paint from gas runoff also. I have been told that BP contains more alcohol than most. I will try another brand for a while see what happens

[Hank]

I just ordered insulation material for my fuel lines, in dealing with the vapor problem. At what pressure should the electric fuel pump be run? I am still having a hard time understanding why these older cars vapor lock and the new do not. We are still pumping fuel thru fuel lines to a distribution point!Would a orfice installed at the carb help? This would maintain liquid to the distribution point.

[Hank]

I just ordered insulation material for my fuel lines, in dealing with the vapor problem. At what pressure should the electric fuel pump be run? I am still having a hard time understanding why these older cars vapor lock and the new do not. We are still pumping fuel thru fuel lines to a distribution point!Would a orfice installed at the carb help? This would maintain liquid to the distribution point.

[Chucks Stude]

Pressurization raises the boiling point of a liquid. Some modern fuel systems run at pressures as high as 65 psi and that is why they do not boil over. An electric fuel pump on a carburated car should not be much over 4 to 5 psi. At pressures higher than that, you could overpower the needle and seat assy in your carburetor, and flood it. If you are going to put in an electric fuel pump, you need to have either an overturn kill switch, in case of accident, or a manual on/off switch. IMHO.

[Chucks Stude]

Pressurization raises the boiling point of a liquid. Some modern fuel systems run at pressures as high as 65 psi and that is why they do not boil over. An electric fuel pump on a carburated car should not be much over 4 to 5 psi. At pressures higher than that, you could overpower the needle and seat assy in your carburetor, and flood it. If you are going to put in an electric fuel pump, you need to have either an overturn kill switch, in case of accident, or a manual on/off switch. IMHO.