vapour lock symptoms

[hemicross]

just wondering if anybody out there can help me.  My 1973 Challenger with a 383 runs fine for 45 minutes then stalls.  After it sits 15 to 20 minutes it starts back up until it gets hot then stalls again.  Running on the highway, it runs all day.  In city stop and go traffic, it stalls between 40 and 45 minutes.  So far I put in a new coil, new fuel pump, filter, removed tank and checked tank. Sending unit sock all clean.  It seems to be fuel related, not electrical.  I have run the vehicle the gas cap off and same thing.  Can anyone please help?

[msbaugh]

Do you have a return line or a fuel pressure gage?

[hemicross]

no pressure guage  and no return line     getting ready to put in a electric pump   hopefully that is the problem

[brads70]

Try and find fuel with no ethanol. The more ethanol the quicker it boils in the carb. Mine has never stalled  but acts up while sitting in traffic. I have to keep revving it up to clear out the carb when it starts to stumble. Pluming in a return line will help. I too am going to install an electric pump soon and will install a return line then.

[msbaugh]

It might be difficult to find fuel with out ethanol, if you go to an electric fuel pump a return line would sure help. It can stop vapor lock because it keeps excess fuel moving around. Also get a pressure regulator and a gage. That will be a good addition and can also help identify any future issues

[Bullitt-]

I'm not saying this is your problem but a local guy has a "73 Charger 400CI that had no issues on the highway but would die when hot around town and not start till it cooled down.     . It turned out to be the ECU was getting hot, he relocated it to a cooler spot.
Check for spark when she dies.

[msbaugh]

You also want to keep the fuel lines away from heat sources.  If you can custom bend your own It would make it easy

[hemicross]

all fuel lines close to any type of heat  are all wrapped first with rubber fuel line then braided stainless over that    i even put a ceramic  3/4   inch spacer between the carb  and manifold

[NCtrueconservative]

Try and find fuel with no ethanol. The more ethanol the quicker it boils in the carb. Mine has never stalled  but acts up while sitting in traffic. I have to keep revving it up to clear out the carb when it starts to stumble. Pluming in a return line will help. I too am going to install an electric pump soon and will install a return line then.

I can relate to this!!! Cleaned out my carb the other day, and the dadgum ethanol had left its sticky residue all over the place.  That's "going green" for ya

[drewcrane]

Yes we have these issues alot up here in Colorado they use 5 different types of fuel here(ALL HAVING SOME AMOUNT OF ETHANOL) depending on season,

 and I drive mine all year so there are different times when I get vapor lock,spring being one of those times due to temps that can get down below zero at night and pop back up the next day in to the 70,s

I know what you are saying drives fine for a while and then run in to a store , or stop at a light and it just sputters and pukes and and then it clears up,

 I have done the following and have helped it alot,

return line a must,electric pump is also nice to help pump hot fuel out and bring cooler fuel in to the carb,or carbs,those 2 things will atleast minimize some of it,

and I have rerouted my fuel line several times and have tried to make it get in and out of the engine compartment as fast as possible so less fuel line under the hood the better, I have seen alot of people run the fuel line out side the compartment along the inner fender and have it come in at the radiator support right up to the carb,

But return line and an electric pump.

My theories are like the ones stated above the fuel has  changed so much for fuel injected cars that it is not made for carb cars, and the fuel sits in the bowls and the part that lights is boiled off leaving a fuel that wont light as well struggling to get the engine going ,I know what I just said is not very accurate but I have had vapor lock issue in alot of cars so it is the only thing that makes my head not think about it too much  

[GranCuda1970]

Does adding fuel stabilizer help?

[drewcrane]

Does adding fuel stabilizer help?

That is a good question, I have never tried that might help 

[brads70]

Does adding fuel stabilizer help?

I'm not 100% sure but I highly doubt it. The ethanol is still there....

[drewcrane]

I'm not 100% sure but I highly doubt it. The ethanol is still there....

Yea the deathenol I DO know people that mix in some race gas I have done that 111 octane ,I bought 5 gallons and add a gallon to a tank and it seemed to help, but it was summer and I ddint have that issue with summer gas, but after advancing the timing the car ran better