1. Verify the Fuel Pump Replacement:
* Did you actually replace the pump? It's possible there was an error in the installation, or a faulty pump was used. Double-check the pump's connections, ensuring the electrical connector is secure and the fuel lines are properly attached. A faulty fuel pump relay is also a possibility.
* Fuel pump relay: Locate the fuel pump relay (check your owner's manual or online resources) and ensure it's not faulty. You might try swapping it with another relay of the same amperage rating (if safe and you know how to do so).
* Wiring: Inspect the wiring to and from the fuel pump for any damage, corrosion, or loose connections. A broken wire can interrupt power to the pump.
* Fuel Pump Pressure Test: The most crucial step. You NEED a fuel pressure gauge to measure the pressure at the fuel rail. This will definitively tell you if the pump is delivering fuel and at the correct pressure. If pressure is low or absent, the problem is either the pump itself (despite the replacement), the wiring, the relay, or a clogged fuel filter.
2. Rule out other potential issues:
* Fuel Filter: A clogged fuel filter will restrict fuel flow, even if the pump is working. Replace the fuel filter—it's a cheap and easy fix that often solves this type of problem.
* Fuel Pressure Regulator: This regulator controls fuel pressure. A faulty regulator could be leaking fuel or not maintaining the correct pressure. Again, a pressure test will reveal if this is the culprit.
* Clogged Fuel Lines: Though less likely after a fuel pump change, check the fuel lines for any blockages.
* Injector Issues: While unlikely to cause *zero* pressure, faulty injectors could be contributing to a no-start situation *if* there's some very low pressure. This should be checked *after* confirming adequate fuel pressure.
* Ignition System (despite the cap & rotor change): While you replaced the distributor cap and rotor, a faulty ignition coil, ignition module, or crankshaft position sensor could prevent the engine from starting and might be misinterpreted as a fuel delivery problem. A no-spark condition would prevent the engine from running, even with fuel. Test the ignition system if the fuel pressure is okay.
Troubleshooting Steps:
1. Pressure Test: This is the absolute first thing you need to do. A fuel pressure gauge is essential.
2. Fuel Filter Replacement: Cheap, easy, and often the culprit.
3. Inspect Wiring: Look for any damage to the fuel pump wiring.
4. Check Fuel Pump Relay: Swap it (safely) or test it.
5. Ignition System Check: If fuel pressure is confirmed, check for spark.
Important Note: Working with fuel systems involves flammable materials. Be extremely cautious, work in a well-ventilated area, and disconnect the battery negative terminal before starting any work. If you're not comfortable with automotive repair, take your Blazer to a qualified mechanic.
