1. Check the Fuel Pump:
* Listen for the pump: Turn the ignition key to the "on" position (don't start the engine). You should hear a brief humming sound from the fuel pump (usually located near the fuel tank). If you don't hear it, the pump might be faulty or not getting power.
* Check the fuel pump relay: Locate the fuel pump relay (consult your owner's manual or a wiring diagram). You can try swapping it with a known good relay of the same type to see if that solves the problem.
* Check the fuel pump fuse: Similarly, check the fuse for the fuel pump (again, consult your manual). A blown fuse is a relatively easy fix.
* Check fuel pressure: This requires a fuel pressure gauge. The gauge connects to the fuel line at the carburetor. The pressure should be within the manufacturer's specifications (check your owner's manual). Low or no pressure indicates a problem with the pump, fuel filter, or fuel lines.
2. Inspect the Fuel Filter:
* A clogged fuel filter can restrict or completely stop fuel flow. Locate the filter (often near the fuel pump) and replace it. This is a relatively inexpensive and easy fix, and should be done regularly as part of routine maintenance.
3. Examine the Fuel Lines and Connections:
* Look for any cracks, kinks, or leaks in the fuel lines running from the tank to the carburetor.
* Check all fuel line connections for tightness and ensure there are no leaks.
4. Investigate the Carburetor:
* Check the fuel inlet: Make sure the fuel line is properly connected to the carburetor's fuel inlet. Sometimes a simple loose connection is the issue.
* Check the carburetor's float level: A low float level might prevent fuel from reaching the carburetor jets. This requires some carburetor knowledge and possibly disassembly.
* Check for clogs in the carburetor: Debris can clog the jets within the carburetor. This is more involved and might require cleaning or rebuilding the carburetor.
5. Other possibilities:
* Fuel tank: A problem within the fuel tank itself, such as a blockage or a punctured tank, can prevent fuel from reaching the pump.
* Wiring: Check the wiring harness for any damaged or loose connections related to the fuel pump and other fuel system components.
Important Considerations:
* Safety First: Gasoline is flammable. Work in a well-ventilated area, and avoid sparks or open flames.
* Manuals are your friend: Your owner's manual and a repair manual specific to your 1990 Chevy pickup will be invaluable resources for locating parts, checking specifications, and troubleshooting.
* Professional Help: If you're not comfortable working on your fuel system, it's best to take your truck to a qualified mechanic. Improperly handling fuel can be dangerous.
By systematically checking these areas, you should be able to pinpoint the cause of your fuel delivery problem. Remember to replace parts as needed and always consult your vehicle's manuals.
