Possible vapor lock or heat soak issue ?

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DartThis74

DartThis74

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My '74 dart sport just started producing issues that never have happened before. My dad drove it several weeks ago and after 10 minutes or so the car surges and sputters like it is out of gas. Started it up and drove it to the gas station around the corner and filled up with 11 gallons, so it had at least 5 in it when problem started. Attempted to drive it home and dies like it is out of fuel. He starts it and drives it a short distance until it dies and does this several times to limps the car back home to the driveway.

Today, i had the car idling in the driveway for about 10 minutes... No issues. Drive down the street... No issues. Then! When I decided it could possibly be fine I accelerate hard a couple of times and it started acting funny. I turned around immediately and it surges and dies I coast into someone's driveway. It cranks right up and drive about 100 feet and it dies... I did this several times until it just simply wouldn't start anymore.

We have driven this car several 100 miles after finally restoring it without much issue until now. I drove it for near an hour a couple of days before it started acting up when my dad drove it. We recently converted the ignition over to the GM hei kit supplied here
http://www.forabodiesonly.com/mopar/showthread.php?t=204177

Engine is a 360 with long tube headers, and radiator is a champion 3 core. Carb is a 750 Holley with mechanical fuel pump. Thank you for any help or suggestions!
 
Sounds like it is running out of fuel.
 
I did forget to mention that I put in a brand new fuel sending unit and sock. But if it was clogged then why would the car idle fine for quite some time and drive with no issues until about 10-15 minutes into driving. Is the heat loosening up gunk or something ?
 
Fuel pump not enough or not working properly, float setting too low, no vent on the gas tank and it's pulling a vacuum. Could be lots of reasons.
 
When sitting around idling in the driveway the psi was sitting around 7 on the fuel pressure gauge. If the car is having issues getting fuel to the engine if I drive the car and it dies on me I guess I should push the throttle linkage and look in the carb to see if anything is squirting in ? Right now the car is sitting in someone's driveway down the road...
 
A recent fill up not long after the tanker truck was there? Get a load of water and muck in your tank maybe?
 
You should be looking for a strong squirt of fuel, yes, but the time to do it is not when it's been sitting awhile. The time to do it is immediately when it exhibits the problem. I thought that was pretty evident. I guess not.
 
nm9stheham said:
Roger.... clogged filter or fuel sock on the pickup in the tank or similar
Click to expand...

This. I had the same problem and it would only do it as the tank started getting low. The floating crap to gas ratio would start to plug the line and would starve it for fuel. When I took the tank out all of the sealer had come loose and plug the line.
 
DartThis74 said:
I did forget to mention that I put in a brand new fuel sending unit and sock. But if it was clogged then why would the car idle fine for quite some time and drive with no issues until about 10-15 minutes into driving. Is the heat loosening up gunk or something ?
Click to expand...
The motion can stir up the crud. It can be other things, but the initial symptoms point to the fuel being blocked or not being pumped. If the tank was not dropped and cleaned out 100%, it can very well just be the crud still in the tank after 40+ years. Start with the most likely problems, work on those, and if it is proven to not be that, move to the next most likely culprit.
 
Well I finally got my car back home. Went back to the car about 2 hours later after it had cooled down and it took a few minutes to get it running. After starting it was trying to die, so I had to baby it to let it warm up a moment. I was able to drive it back home about 2 miles down the road and it didn't have any issues.
 
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