1978 k10 not getting gas

1978 k10 Chevy Truck- coughs and sputters on 300 mile drive home. when I get to fixing it then will not start. changed out fuel filter- no change. changed out fuel pump-no change. troubleshooting: can suck fuel to the fuel pump but the "cam" rod appears to be stuck or not moving. does give some vacuum pump effect though. dual tank selector switch is clicking so solenoid appears to be good. appears that electric fuel pump is the route to take. buy AC delco fuel pump and mount near selector switch but now cannot figure out how to know which wire is "hot" to connect to near the dash. What is the correct method (in detail) to find the hot wire so that I turn ignition key, wait couple of seconds then whoala, I have fuel to the fuel filter off of the carb?

Brent

User a test lite on the various circuits in the fuse box to see which is ignition powered.

1978 k10 Chevy Truck- coughs and sputters on 300 mile drive home. when I get to fixing it then will not start. changed out fuel filter- no change. changed out fuel pump-no change. troubleshooting: can suck fuel to the fuel pump but the "cam" rod appears to be stuck or not moving. does give some vacuum pump effect though. dual tank selector switch is clicking so solenoid appears to be good. appears that electric fuel pump is the route to take. buy AC delco fuel pump and mount near selector switch but now cannot figure out how to know which wire is "hot" to connect to near the dash. What is the correct method (in detail) to find the hot wire so that I turn ignition key, wait couple of seconds then whoala, I have fuel to the fuel filter off of the carb?

Brent

been a while since I had this issue. I remember that the install of the fuel pump on the side of the block can be tricky. may have to rotate the engine so it is at the proper position...

put old fuel pump to fuel line move pump arm does it suck fuel ? if so then the cam maybe damaged ..never seen it before but I guess this old anything can happen.

installing the electric pump on the fuel line will require a regulator and the connection to the return line. fuel pressure is I guess 6-7 PSI. with typical q jet carb...

Remove the fuel pump and try to reinstall it as j caT says. You might not have it on the camshaft eccentric properly. Sometimes people used to manage to get the arm lever hooked over the cam, thus it wont function. I've never seen a cam eccentric for the fuel pump get so worn out it wouldn't function. Going with an electric pump creates problems you don't need with this old,(but good), truck.

Remove the fuel pump and plate. Where is the rod? All the way up/down/middle? Is the fuel pump arm under the rod? Push on the rod and see if it moves. If so pull it out put some heavy grease on it and put it back. Should stay in place so you can mount pump under it.
Good luck