Rebuilt the 63 Dart 225 over the course of a year (1st time rebuilding an engine). Prior to the rebuild, I had rebuilt the Carter 1bbl carburetor with a Daytona kit. Carb was functioning fine at the time the engine got pulled for the rebuild.

The engine rebuild took nearly a year with me working on it on/off. Like an idiot, I didn't put Sta-bil into the gas tank until 1/2 way through the year the full tank was just sitting. But once the engine was back in the car, everything seemed fine.

Cut to me daily driving the car. The car stutters and stumbles sometimes after it's been driven at fwy speeds and then shut off for about 20-30 minutes. It will start fine, then slow down, stutter, run roughly then smooth out and run normally. It always recovered and I thought 'eh, a carb rebuild, I'll get to it'.

I recently drove the car on the freeway, stopped for lunch, then came back an hour later to drive away. I started the car, it ran for a moment, roughened up, then died. Tried starting it, and it wouldn't catch. Noticed there wasn't any fuel in the carb throat, pulled the line to the carb, tried cranking the engine over and no gas came up from the tank. Thought 'crap, the fuel pump: it's been the fuel pump this whole time, not the carb!" Had the car towed home. That took a couple hours.

At home, checked the in-line filter and it was dry and clear. Tried cranking the engine over again and this time, fuel! Then I thought, "CRAP! There has to be sediment in the tank. Ok, I'll get to it."

This evening I pulled the fuel tank out, blew out the fuel line from the front to back with compressed air. Inspected the interior of the tank, and it's still coated with the red sealant that was put on two years ago when I had the tank boiled out and cleaned then. Everything's in place, and I see only a minuscule amount of sand in the bottom of the tank, but otherwise it's all clear.

What could be wrong? Could it still be the pump? The pump has worked well, but is a NOS aftermarket pump and I have been warned modern fuel eats old fuel pump diaphragms after a time. I just don't understand what could be the issue....

Did your car run OK cold? I have to wonder about vapor lock if this only happens when hot. The start-up problem when shut down hot for lunch is a posible indication, though I would expect it to be OK after cooling for a whoel hour. And it surely should have started up cold.

There are check valves at inlet and outlet of the pump, and if either fails, it will not work. Parts can fail at any time.... YOu have done the basic pump test: Put the output line from the pump in a can and crank the engine and see what comes; take some care since, if the pump is good, it can shoot gas out several feet. It should pump out around a pint in 30 seconds but most will put out more. Since you got not gas, it is either the lines or the tank plugged, a broken fuel line, or the pump bad.

ALSO, CHECK YOUR OIL FOR ANY SMELL OF GAS. A ruptured pump diaphragm would put gas into the crankcase and possibly damage your fresh rebuild. If the pump does turn out to be bad, you might consider an oil change anyway. How many miles are on this engine now?

Look at the rubber lines out of the tank and into the pump; any cracks will allow air to be drawn in. I'd just replace them on principle while you are there.

I would absolutely dump all the old fuel before any more driving, if you have not done so already; it will do a number of bad things in the engine, like gumming up valves.

Yes, it always runs ok cold. Never have experienced vapor-lock in this car in 17 years of owning it, but I guess given the right circumstances it could happen.

I did not know this.

I'm going to replace the aftermarket pump with my original Carter fuel pump that I rebuilt with a new diaphragm kit that uses modern materials. This will provide a good excuse for me to replace the NOS one I have been using. I cranked it over for about 10-15 seconds and some fuel did come out, but nowhere near the amount you're describing.

Will do. Somewhere around 5K now, I'd have to check to be sure.

These do need replacement. The rubber line going from the hardline into the pump is somewhat brittle and the end split easily. The line in the rear seems nearly as petrified. Good suggestion, thanks.

Anyone else have thoughts, while I work on all this?