I need a fuel line diagram for all fuel lines. that shows which one is fuel feed, fuel return & fuel vent. all at the tank.

the fuel is constantly rotating round the fuel lines, the fuel is pressurized, so any fuel that is not used by the injectors is sent back to the tank.. this give a constant flow and pressure to the tank. the pressure in the tank is regulated by the pressure relay that lets air into the tank to lower the pressure. this is regulated by the ecu and your speed. if the pressure drops or is to high in the tank the engine can cut out on the fuel rail there is a fuel pressure regulator this keeps pressure on the fuel line coming into the injection system. some systems have duel line feeds from the tank for 2 rail systems, this system was not reliable due to the amount of feed pressure needed to fuel 2 lines. and can cause pressure leaks. some systems have a pressure regulator controlled by the ecu on the return line, this is more fuel efficient as it keeps the fuel at a steadier flow back to the tank and give a better fuel spray into the engine. hope this help you.

Can you identify or remember which pipe on the sending unit, the pump module, is the main outlet from the pump?
The three lines are the main feed or pressure line to the engine, the return line from the engine to the tank-this line is often smaller than the main line. And the third line is not a fuel line, but the vent line for fumes from the enclosed tank to the charcoal canister. This line may be identifiable by pipe diameter being smaller, or sometimes using rubber hoses with it, or maybe just a little offstanding from the other two lines. The main line (pressure line) will be the line that has the fuel filter in it. You can identify the main line this way, then just figure out where it connects onto the tank, and sort out the other two lines-the return line and the (?smaller?) vent line.

The pump line, or feed line, goes to the fuel filter and then to the engine's fuel rail. A return line leaves the fuel rail and sends gas back to the tank. Usually, the feed line is slightly larger than the return line, not always.
The third line is a vent line for emission controls-routing gas fumes from the tank to the charcoal canister, where it is stored and later sent to the engine to be burned.

fuel pump is in the tank try to get most of gas out of tank then you need to unclip pressure line and return line and vent line unplug electric connector and remove tank there usually are no pictures for this if you need pictures you should hire it out

There should be only 2 fuel lines and a vent line coming out of the tank. The vent line is for fumes that are routed to the charcoal canister-part of the evaporative emissions system, and the two fuel lines are the main feed line to the filter and then on to the engine, and the other gas line is the return line from the engine back to the gas tank. All fuel injected systems have a feed line and a return line. The return line is for fuel not used but sent back to the tank by the fuel pressure regulator.
Nowadays, rather than replace metal lines, shops can use the plastic fuel lines (they don't rot!) and special connectors to fit new fuel lines. YouTube has lots of videos on replacing fuel lines.

if you take and clamp off the hoses and remove them from the tank,then support the fuel tank,remove the fuel tank holding straps then lower the tank,disconnect the wiring and make sure there is nothing else connected to the fuel tank,remove fuel tank transfer any components to the new tank and re-install.

Fuel Tank Assembly Removal & Installation Single Tank To Remove:

1. Before servicing the vehicle refer to the precautions at the beginning of this section
2. Relieve fuel system pressure (See: Fuel System Relieving)
3. Disconnect the negative battery cable
4. Raise and support the vehicle
5. Drain the fuel tank in an approved container
6. Remove or disconnect the following:
   • evaporative emission (EVAP) canister Disconnect fuel lines for single tank
     
     
   • Chassis fuel lines (B) at the fuel tank (A)
     1. Cap the fuel and EVAP lines to prevent possible fuel system contamination
     Disconnect EVAP vent line
     
     
   • EVAP vent line at the fuel tank clip (E) Disconnect vent hose and filler hose
     
     
   • Vent hose and filler hose clamp (D, B)
   • Vent hose and filler hose from the line
   Fuel tank removal
   
   
7. With the aid of an assistant or a suitable jack support the fuel tank
8. Remove or disconnect the following:
   • Fuel tank strap attaching bolts
   • Fuel tank straps
9. Carefully lower the rear of the fuel tank slightly
10. Remove or disconnect the following:
    • Fuel sender cover Fuel tank connections
      
      
    • Fuel sender and the fuel pressure sensor electrical connectors
    • Fuel tank
11. Place the fuel tank in a suitable work area Fuel lines at the tank
    
    
12. Remove or disconnect the following:
    • Fuel feed and return lines (C) from the fuel sender and the retaining clips
    • Fuel pump assembly from the fuel tank
    • EVAP line from the fuel tank roll over valves (B, D) and the retaining clips (A)
    • Fuel fill hose and the vent hose from the fuel tank
    • Fuel tank

To Install:

1. Install or connect the following:
   • EVAP line to the fuel tank roll over valves and the retaining clips
   • Fuel pump assembly to the fuel tank
   • Fuel feed and return lines to the fuel sender and the retaining clips
   • Fuel fill hose and the vent hose to the fuel tank; torque hose clamps,
     1. Torque to: 22 lb-in. (2.5 Nm)
2. With the aid of an assistant or a suitable jack support and partially raise the fuel tank front end first
3. Install or connect the following:
   • Fuel sender and the fuel pressure sensor electrical connectors
   • Fuel sender cover
4. Fully raise the fuel tank
5. Install or connect the following:
   • Fuel tank straps
   • Install the fuel tank strap attaching bolts;
     1. Torque to 30 lb-ft. (40 Nm)
   • Fuel fill hose and the vent hose to the lines;
     1. Torque hose clamp to 22 lb-in. (2.5 Nm)
6. Torque the vent hose clamp,
   • Torque to: 22 lb-in. (2.5 Nm)
7. Connect the EVAP vent line to the fuel tank clip
8. Remove the caps from the fuel and EVAP lines
9. Install or connect the following:
   • chassis fuel lines at the fuel tank
   • EVAP canister
10. Lower the vehicle to the ground
11. Fill the fuel tank with clean fuel
12. Install the fuel filler cap
13. Connect the negative battery cable
14. Use the following procedure to inspect for leaks:
    • Turn the ignition on for two seconds
    • Turn the ignition off for 10 seconds
    • Turn the ignition on
    • Inspect for fuel leaks
15. Install the engine sight shield
16. Road test the vehicle to check performance

Fuel Pump REMOVAL & INSTALLATION 1.9L Engine To prevent excessive fuel spillage, whenever the tank is removed from the vehicle it should be no more than 1?2 full. Removal of the fuel pump module assembly requires the removal of the fuel tank.

1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
2. Properly relieve the fuel system pressure.
3. Remove or disconnect the following:
   • Negative battery cable
   • Fuel feed and return lines from the filter/pressure regulator
   • Fuel pump vapor line from the fuel tank vent pipe
   • Fuel pump module retaining ring with service tool SA9156E. A 1?2 inch breaker bar will loosen the lockring
   NOTE: To prevent bending of the sending unit float arm, lift the pump module up slightly to disengage the orientation tabs in the tank. Rotate the module 90 degrees clockwise until the fuel lines are facing the 1 o'clock position.
   • Fuel pump module from the fuel tank until the bottom of the pump module is close to the fuel tank opening
   • Tilt the pump module approximately 45 degrees to the right hand side of the tank and lift the pump from the fuel tank
   • Fuel pump to tank seal and discard it
   To install:
   
4. Install or connect the following:
   • Fuel pump module into the fuel tank by orientating the float to face the right side and tilting the module approximately 45 degrees
   • Fuel pump into the tank and rotate the assembly 90 degrees counterclockwise to align the module tabs with the slots in the tank
   NOTE: The fuel pump retaining ring cannot be properly installed if the flange locator tabs are not aligned with the slots in the fuel tank.
   • Retaining lockring with tool SA9156E
   • Vapor line to the fuel tank vent pipe
   • Fuel feed and return lines to the filter/pressure regulator
   • Fuel feed, return and EVAP canister purge line in the fuel tank retaining clip
   • Fuel tank
   • Negative battery cable
5. Start the vehicle and check for leaks, repair if necessary.

2.2L and 3.0L Engines

1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
2. Properly relieve the fuel system pressure.
3. Remove or disconnect the following:
   • Negative battery cable
   • Fuel tank
   • Fuel lines from the fuel pump module cover
   • Fuel pump module retaining ring with a Sending Unit Wrench, J43827
   • Pull the retaining clip toward the float arm and lift up
   • Fuel pump straight up from the fuel tank
   • Fuel pump tank seal and discard the seal
   • Fuel feed line from the bottom of the fuel pump cover with Clamp Pliers J43914
   • Fuel pump electrical connector Fig. 1: Remove the fuel pump cover lockring-2.2L and 3.0L engines
     
   To install:
   
4. Install or connect the following:
   • Fuel pump feed line to the cover
   • Fuel pump electrical connector
   • Fuel pump to the new seal
   • Fuel pump cover lockring with tool J-43827
   • Fuel lines and wiring harness
   • Fuel tank
   • Negative battery cable
5. Start the vehicle and check for leaks, repair if necessary.

Vent return,or filter return,by pass.One is a by pass,one is a vent ,to the canister purge.the other is the main pressure line.

Older chev mechanical pumps had a single feed line. Newer ones had a feed line and a return. The steel lines on the sending unit are feed and return. If there was a vent line it would be a seperate line going to the top of the tank all by itself. If everything is hooked up correctly you should have about 7lbs pressure at the feed line.The needle valve in the carb will not allow leak-back if it is working correctly. If you have a Qjet carb, the bottom bowl plugs sometimes leak... that is a different problem not caused by supply.