Last week the wife drove the 80 out to Home Depot about 4 miles. The car quit on the way back. Said it acted like it ran out of gas. [ Had Gas ] Pulled the air cleaner lid , pumped the carb , had gas squirting and started right up. Drove home without problem. I put a new Wix fuel filter in the carb. Week later she goes for a drive and at about 3 miles the same thing , acted like it ran out of gas. This time no gas squirting in carb. Poured gas in carb, started right up and quit. No gas getting to carb. Simple deduction must be the fuel pump. Today I figured I would pull off the fuel pump but before I did I pulled off the air cleaner lid and actuated the throttle . Had good solid gas squirting in the carb. Car started right up and ran fine. I didn't take it for a drive I didn't want to be stranded, that's the wife chore, but it ran with no issues. Everything is stock, car runs great till it quits, new filter, has gas, not hot enough for vapor lock. I didn't check fuel pump pressure but the gas flows freely out of the supply at the carb, the car is on a forward down slope . I'll see if I can find a gauge. My question is : Could it be the pump? or what else

 

Does the car sit for long periods of time? If so I would suspect crud in the tank or the fuel line.

 

Could be the gas tank sock, but that's pretty rare.

 

As I stated in my original; post the filter was changed last week and it didn't look bad. . Drive the car at least once a week with no problems. The carb is the original Quadrajet with the inlet filter , the only filter GM put in this particular model. Checked out the fuel pressure lends at the local parts stores, both only had high pressure set ups for checking fuel injection cars. Ordered a new pump anyway. I have had a lot of cars and never had a fuel sock plugged up but always the first time . Sure don't want to get into pulling the tank. Question: would gas flow freely through the pump? Seems like the diapram would hold it back.

 

Trying to remember if gas exited the pumps port to the carb when I changed my lines years ago. I believe that it will free-flow due to the tank being higher than most cars and the diaphram is not really a check valve but an assist valve. But not sure.

Your new pump is three port? I really doubt its the pump. Them things go forever. I think its a carb issue. Needle Valve, Seat, Float, who knows?

 

Pull the line off at the tank and at the pump and blow air through the line. You might be surprised at the junk that comes out. With the cat **** ethanol that we have to deal with today nothing surprises me.

 

NTFday is making a good point, the old rubber will dissolve and pug lines, I had to replace them on my old chain saws. Squees your rubber fuel lines together and see if they stick in that squeezed shape, thats an indicator the inside is gooey


I've had a string of bad pumps and I had crap in my tank that would block the fuel flow.

the bad fuel pumps
The fuel pumps can fail slowly or all at once. This sounds more like a blocked fuel line/ low pressure problem. The slow failing fuel pump problems will permit it to pump at low volume ( 2-3 psi on mine) and fill the carb very slowly. If the she was driving at moderate speeds with out getting on the highway it may be a low volume problem. If you have a fuel pressure gauage you can test with, I would try testing it first. Then pull the pump and look at he pin that the pump lever pivots on. It could be pulling apart and just barely working. If so dont go back to a carter pump, go to an edelbrock or similar racing style pump and possibly a fuel pressure regulator. If your car is all stock and you want it to stay stock looking this could be a recurring issue like I had to deal with until I finally gave in

for a blocked fuel line
I had a 66 mustang back in high school that a douche bag had stuffed a dead branch into the gas tank for some prank/ revenge thing ( different story) any ways it would do the EXACT same thing you're experiencing, just shutting off for no reason. I ended up droppping the tank and flushing it to get the problem to go away. If you are going to drop the tank, first try blowing compressed air back through the lines from the pump. You'll see if anything blows out of the strainer into the tank. If it doesnt then dont bother with the tank. If you see the strainer coming apart, replace the sender

Generally the slow failing fuel pump will restart immediatley with some fuel to prime it and it will continue to run fine at idle. When I had the blockage it was hit or miss for immediate restart depending if the blockage settled again to allow flow
good luck
Scott

PS
I've got 3 different gas psi gauges and 3 different water temp gauges in my car now to try and see a problem before it happens or gets bigger. 2 each in line and 1 each in the cabin. Paranoia is a bitch

 

It will/ might flow a little but not freely or it wouldnt pump. There would be a check valve to prevent back flow. The pump is lower than the tank and fuel will flow to it, but not up to tthe carb. What did you order for a pump. Did you pull your pump yet? post pics of the inside when you do


you can see the parts starting to fall out

swaged fingers that hold the pin in

you should have this many parts

 

Can you get one of those cameras to eyeball the sock in that 80 tank? I would probably do that before starting to disassemble and replace stuff (actually, on my 68 I could just look in through the large filler hole).

The wife doesn't drive mine because she can't drive a manual, but I have to stay on top of the cars she DOES drive so I don't have to deal with her breaking down somewhere.

You can get a USB Borescope for your phone for 20 - 35 bucks (just looked this up... didn't know they were available that cheap!):

 

Vapor lock?...... see Apollo 13 the movie.

 

If you have ruled out all of the above fuel delivery issues, it is possible that it's an ignition component that fails when it gets hot. I used a can of compressed air to blow on the electrical component to cool it down to see if it made a difference. Jerry