Technical Vapor lock or air leak.

Got the 54 olds with 324 running great. I live by the coast with no hills. Never once had a problem with hard starts or hesitation. Took the car up to Austin for the Lonestar roundup. First cruise up south congress(long uphill stretch with lots of lights and traffic) car stalls out and dies. No gas in fuel filter. Towed back to house. Tightened all fittings and primed carb. Fired right up. Topped off with gas. Drove out to show all around Austin not a problem. Many hills. Next day tank about half full stalled out again going uphill. No gas in filter. Primed and fired back up.

Next day tried to drive back home about 4 hrs. Drove 3 hours on highway. Made about 1 hour away at about half tank. Started stalling again up long uphill. Threw it on trailer and towed rest of the way.

Engine never gets over 180. Only happens at about half tank(yes there is still fuel in tank) no gas leaks anywhere. And only happens uphill.

Air leak or vapor lock or both. I only have 3 connections before mechanical fuel pump. They are all tight. New tank and sender and new mechanical fuel pump. Thinking about pressurizing fuel system from the fuel pump back and checking for leaks or should I just bandaid the problem and add an electric pump by the tank and use if needed?

 

Is the gas cap properly vented?

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Next time it happens, remove cap and see if it starts and runs.

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Cap is vented.

 

Crap in the tank plugging pickup tube when going up hill, or rusted/bent pickup tube in gas tank.

 

My guess is that you're sucking air inside tank once the tank gets below half full.

 

New tank and pickup tube. Have run tank with 2 gallons in it before and never had issues.

 

Sounds like vapor lock. Went through similar issues with my Cadillac, an electric fuel pump solved the problem. Also if you are using an AFB carburetor limit the fuel pressure to no more than 3 psi.

 

Clue provided. It didn't do this previously, new tank and pick up...I'd start there.

 

Disconnect vent and blow out with HP air, solved my stalling issues when I thought it was carb or coil (overheating).

 

What type of tank is it? Stock replacement?
If it is I bet your pickup tube has fallen off.