1. Fuel Pump and System:
* Fuel Pump Relay: This is the most likely culprit. A faulty relay prevents the fuel pump from powering up. Swap the fuel pump relay with another relay of the same amperage (check your owner's manual or online) to see if the problem moves.
* Fuel Pump Itself: The pump might be failing, even if it's getting power. Listen carefully near the fuel tank for the whine of the pump when you turn the key to the "on" position (before cranking). A weak whine or no whine points to a pump problem. Fuel pressure testing is crucial to confirm this.
* Fuel Filter: A clogged fuel filter will restrict fuel flow, preventing the injectors from receiving enough fuel.
* Fuel Pressure Regulator: A faulty regulator could be leaking pressure, preventing sufficient fuel delivery to the injectors.
2. Computer/Electrical Issues:
* PCM (Powertrain Control Module): The PCM controls fuel injector operation. A faulty PCM can cause a no-start condition even with spark. This is less likely, but possible. A scan tool capable of reading PCM codes is needed to diagnose this.
* Cranking Sensor/Cam Sensor: Though you have spark, a faulty crankshaft position sensor (CKP) or camshaft position sensor (CMP) can prevent the PCM from commanding fuel injection. The PCM needs these signals to know engine position and timing for proper injection.
* Wiring Harness: Check for damaged, corroded, or loose wiring connections, particularly those related to the fuel system, PCM, and sensors. This is often overlooked.
* Inertia Switch: Some vehicles have an inertia switch that cuts power to the fuel pump in a collision. Check your owner's manual for its location and reset it if necessary.
3. Injector Issues (less likely given your description):
* Injector Circuit: While you *think* there's no injector pulse, verify this with a noid light or a multimeter. A noid light will illuminate when the injector is receiving a signal. This will definitively tell you if the injectors are being pulsed.
* Clogged Injectors: Though less likely to cause a complete no-start, clogged injectors could be contributing.
Troubleshooting Steps:
1. Check for fuel pump operation: Listen for the pump whine and visually inspect the fuel pressure at the rail (requires a fuel pressure gauge).
2. Swap the fuel pump relay.
3. Verify injector pulse using a noid light. Don't rely on assuming there's no pulse.
4. Use a scan tool (OBD1 scanner) to check for diagnostic trouble codes (DTCs). This will help pinpoint the problem area.
5. Inspect wiring harnesses for damage.
6. Check fuel filter condition.
If you don't have experience working on cars, it's best to have a qualified mechanic diagnose and repair the problem. Improper diagnosis can lead to further damage or injury. The fuel system deals with flammable materials, so caution is essential.
