Packard Forum Index » Post-War (1946-54)

Hi Guys, I have been working on this problem for months now and getting frustrated. 1951 Packard 200 Deluxe Ultramatic. Car behaves perfectly until it gets completely warmed up. If I take it downtown, chances are I will be limping the car home or towed (once).
Fuel tank is clean, fuel line is good, rubber fuel line is new, fuel pump rebuilt from Kanter and carb rebuilt. In the shop the glass filter bowl stays full until the car warms up and then the fuel level drops. The fuel will spurt into the bowl for a few seconds and then stop completely, then spurt again. Sometimes it runs out of fuel completely. Gas cap on or off makes no difference. I ran the fuel line into a plastic jug and got around 2/3 cup just cranking the starter for 30 seconds. Is this enough?
Any help will be greatly appreciated I am completely at a loss. Dan

A normal fuel pump with throw 6 plus feet.

That fuel pump should pump like now.

Something is blocked.

RH, I can blow air into the tank with 20# pressure and if I put air to the tank filler, gas will come out of the line at the fuel pump. I can hold air in the line for a while and no leaks in the line anywhere. No obstruction I can find. I used 2'of clear plastic tubing from the carb line to the jug. It took probably 15 seconds just to fill the tubing. Maybe just a bad pump?

Well, three things:

1) atmospheric pressure is 14.7 psi. That's the most the pump can "pull" if the entire system was beyond perfect, but in the real world it cannot even do that. See what comes out at 10 psi, because the pump won't be able to pull a super-strong vacuum, and 10 psi is probably about what it can effectively pull. That might help determine if there is an obstruction. If you can simply use a vacuum pump or vacuum gage on the line itself, that would be a good test.

2) You could simply plug the pump into a vaccuum gage (instead of the bucket) and see what it's doing. That would tell you whether there is a seal or check-valve in the pump that is bad. Could be you sucked up some crap into one of the check valves and it isn't working effectively. One reason I have one of those cheapy see-through in-line fuel filters before the pump, though I know everyone hates those.

3) The starter doesn't crank the engine very fast, but still, could be a bad pump.

4) I know you were putting the pump on where it hadn't been installed in a long time. If for some reason you installed the pump "too far away", e.g. with too thick a gasket or a plate or something else, the effective stroke of the pump will be reduced, and therefore it's effective pumping power. It should still be able to pull a vacuum but it won't be able to pump very much fluid volume, and it will take a long time to pump up to it's maximum vacuum.

Jerome, The gasket I used came from Kanter and is about .020 +or- so I don't think that's a factor. I understand using a vacuum gauge to test the incoming pressure but confused on how to use one on the line to the carb as that is pressure not vacuum. I do not have a vacuum pump so thats out. I'll see if I can rig up the vacuum guage to the rubber inlet hose directly to see what the pump pulls without the line in the equation. Getting way too complicated. Dan

Make sure the rubber gasket in the glass filter is not swollen up and closing off in or out.

Good that the gasket etc. is the same. Probably the pump stroke is ok.

What I was suggesting was hook up a vacuum gage to the input of the pump. That will tell you how much vacuum the pump can pull. It's a simple test. I don't know offhand how much that should be, others could tell you. One not insignificant possibility is one of the check valves got some crud in it and isn't closing properly, and hence you aren't getting enough pump suction.

If its not that, and the glass filter isn't obstructed, the only other thing I can think of is an obstructed fuel line from the tank.

Did you use the insulators in the two mounting holes? Without them there is too much slop that could effectively lessen the throw of the lever to the cam.

Just wondering if your fuel pump has the factory heat shield if the fuel gets to hot maybe its vapor locking

Quote:

Don, I did use the spacers but I'm not sure what insulating they do as they looked like sections of copper pipe.