I was visiting my friend 25 miles away and helping him with his car, and on our way back to his house, my '79 Pontiac Catalina stalled. I called AAA and brought it home. I've determined it's a fuel problem, as it runs with gas being manually put in the fuel bowl through the overflow, and the accelerator pump works.
The fuel pump is original to the car, so I'm suspecting the diaphragm went out. I'm going to pull the line off the carb and crank the engine over with a fuel hose running from the carb line into a gas can to catch fuel to make sure this is indeed the problem. The flare nut going into the carb is slightly rusted to the line, to the point where the threads will turn in the inlet, but the nut doesn't seem to want to turn on the line. How would I go about freeing the nut from the line? The line itself looks to be in pretty good shape. I'd rather not shear the tube off.
My other suspicions are the fuel filter, which is inside the area where that line goes, and possibly a stuck float/ needle, which I'd need to take the carb off to check anyways.
The fuel pump is certainly a likely suspect, between age and ethanol contamination it would be surprising if it was was working at this point.
I would start by soaking the fitting and line in a good penetrating oil for a while and tapping it to try freeing it up. Sometimes though you just have to bite the bullet and wind up replacing the line.
It's worked quite well, I had the car going 75 for a couple minutes on the freeway on Thursday. The car died on Saturday. I did the original Italian tune-up, and I could hardly feel the engine running after I got off the highway. I'm guessing the higher RPMs that day, and the 55-60 mph I was driving on the country route to my friend's made the pump decide to retire.
I actually got the line out of the carburetor without damaging anything. I soaked it in PB Blaster probably 10-12 times and let it soak in overnight.
The test is indicating the issue is inside the carburetor, not the fuel pump. A steady stream of fuel shot out of the line and into my catch with the engine cranking.
The fuel filter is a bit dirty, but not horrible. Holding it up to a light source, I can't see through it, though, so I'm going to replace that.
Feeling like the float and needle are stuck. Would putting a pool of carb cleaner in the bowl clean off any varnish?
It should, best to at least take the top of the carb off to see what's going on in there.
I got both lines off the pump and pulled the pump off without damaging anything. Do I need to put a film of grease on the arm of the pump, where it touches the cam? The old one is dry, seems like motor oil probably gets to it and lubricates the contact patch before it drains back down into the pan again.
I've always put a little grease on those to make sure there's some initial lube there. Not sure if it's necessary but it won't hurt anything.
Seriously consider a carb rebuild with the new, alcohol proof Viton seals and o rings. Your float needle is probably stuck, as you said.
I noticed it almost wants to stall when I push on the gas, then it revs right up.
Either your accelerator pump is not working properly or you have a vacuum leak.
I checked the pump flow again. Doesn't seem to be spraying fuel anymore. Time for a rebuild. Pumped the gas 5x with it off to see if it would flood out. It didn't do anything but start right back up. Lol.
Welcome to the 1970s!
{pear}:wink:
I'd rather be there sometimes. Haha. There's really nothing to scratch your head about on the old cars. There's no computer or position sensors or any of that middleman stuff. It's all mechanical. Works of art, really.
When I get the carb rebuilt I may start using E0 that's around the corner now. A local gas station on the way to a popular boating lake recently switched their kerosene pumps to 100% gasoline for boaters.
Hey, back then we also got to have home entertainment systems like this!
https://www.youtube.com/watch?v=RuQDJnJ3GCk
I got the beast running again after swapping the fuel pump, filter, and replacing fuel hoses.
I noticed it almost wants to stall when I push on the gas, then it revs right up. It didn't do that prior to it dying. It also got better as the engine warmed up, it would stall when it was still cool.
What would cause this? I don't think there's a problem with the accelerator pump. It sprays gas again when I pull on the throttle cable.
https://youtube.com/shorts/0u_aS0IpU9k?feature=share
Ace Ventura finally starting the '70 Monte Carlo, for laughs, I said it when my Catalina started. Haha.