Here's a breakdown of how to check the system, progressing from simple checks to more involved ones:
I. Simple Checks (Visual Inspection and Basic Tests):
1. Visual Inspection:
* Fuel Lines: Inspect all fuel lines for leaks, cracks, or kinks. Pay close attention to the connections at the tank, pump, filter, and fuel rail.
* Fuel Filter: Check the fuel filter for damage or excessive rust. If it's visibly dirty or damaged, it needs replacing.
* Fuel Pump Relay: Locate the fuel pump relay (check your owner's manual or online resources for its location). Visually inspect it for any signs of damage.
* Wiring: Inspect all wiring harnesses related to the fuel system for any damage, chafing, or corrosion.
2. Listen for the Fuel Pump: Turn the ignition key to the "ON" position (don't start the engine). You should hear the fuel pump prime for a few seconds. If you don't hear it, the pump, relay, or wiring could be faulty.
3. Check Fuel Pressure: This requires a fuel pressure gauge that's compatible with your vehicle's fuel system pressure. Consult your owner's manual or a repair manual for the correct specification. The gauge typically connects to the fuel rail's Schrader valve (similar to a tire valve). You'll need to follow the instructions for your specific gauge. Low fuel pressure indicates a problem with the pump, filter, regulator, or lines.
II. More Advanced Checks (Requires Tools and Knowledge):
1. Fuel Pump Test: If you don't hear the pump priming, you'll need to test the pump itself and its relay. This often involves bypassing the relay to see if the pump works directly from power. Warning: Do this carefully; fuel is flammable.
2. Fuel Injector Test: Testing the injectors requires a noid light or a multimeter. A noid light is the simpler method and directly indicates if the injector is getting a signal from the computer. A multimeter can be used to check for injector resistance. This requires some knowledge of automotive electrical systems.
3. Mass Airflow Sensor (MAF) Check: A dirty or faulty MAF sensor can cause a lean fuel condition. Clean the sensor with MAF sensor cleaner (follow instructions carefully), or replace it if cleaning doesn't resolve the issue.
4. Throttle Position Sensor (TPS) Check: A malfunctioning TPS can also affect fuel delivery. This sensor needs to be tested with a multimeter to ensure it's providing the correct voltage signals to the computer.
5. Computer Diagnostics: The most comprehensive test involves using an OBD-II scanner (or a GM-specific scan tool for older vehicles). This will read diagnostic trouble codes (DTCs) from the PCM (powertrain control module), pointing to specific issues within the fuel system or other related components.
III. Important Considerations:
* Repair Manual: A Haynes or Chilton repair manual for your specific 1994 S10 Blazer is invaluable. It will provide detailed diagrams, specifications, and troubleshooting steps.
* Safety: Fuel is flammable and potentially explosive. Work in a well-ventilated area, away from open flames or sparks. Use proper safety equipment.
* Professional Help: If you're not comfortable performing these checks or repairs, take your Blazer to a qualified mechanic. Improper fuel system repairs can be dangerous and potentially damage your engine.
This information provides a general guide. Specific procedures and specifications may vary slightly depending on the exact engine and options in your 1994 S10 Blazer. Always consult your vehicle's repair manual for detailed instructions.
