1. Verify Power and Ground:
* Fuel Pump Relay: Locate the fuel pump relay (often in the under-hood fuse box). Check for power at the relay's coil terminals with the key ON. There should be power on one terminal, and the other should switch ground when the key is turned on. If no power or no switching ground, trace the wiring back to the source (usually the ignition switch or ECM).
* Fuel Pump Power (at the pump): With the key ON, check for power at the fuel pump's positive wire. If there's no power, the problem is likely before the pump. If there *is* power, the pump itself might be faulty.
* ECM Power and Ground: The Engine Control Module (ECM) needs proper power and ground to function. Inspect the ECM's power and ground connections for corrosion or loose connections. A faulty ECM is a less likely, but possible, culprit.
* Injector Power: With the key ON, check for power at the injectors' positive wires. This requires back-probing, which is best done with a multimeter equipped with a piercing probe. You should NOT see power with the key ON until the ECM grounds them individually. However, you *should* see continuity (a closed circuit) between each injector connector and the ECM. If there's no continuity, you have a wiring problem.
2. Check the Fuel Pump Inertia Switch:
This safety device cuts power to the fuel pump in a collision. It's usually located under the dash or in the engine compartment. Make sure it's reset (pushed in).
3. Inspect Wiring and Connectors:
* Look for any visual damage: Check all wiring and connectors related to the fuel pump, injectors, and ECM for chafing, corrosion, or broken wires.
* Check grounds: Ensure all ground connections are clean and tight. Poor grounds can cause intermittent or complete signal loss.
4. Test the Crank Position Sensor (CPS):
The CPS is critical for the ECM to know engine position and determine when to fire the injectors and energize the fuel pump. A faulty CPS will prevent the injectors and fuel pump from operating. This typically requires a scan tool or a multimeter capable of measuring signal waveforms.
5. Test the ECM (Engine Control Module):
Testing the ECM is the most difficult step and often requires specialized equipment. This is best left to a qualified mechanic or auto electrician unless you have experience with automotive electronics.
6. Consider the Ignition System:
While unlikely to directly prevent fuel pump and injector signal, a severely faulty ignition system (e.g., a bad crank sensor or ignition module) could prevent the ECM from functioning properly.
7. Use a Scan Tool (Most Important):
A scan tool (OBD-I for a 1987 vehicle) can retrieve diagnostic trouble codes (DTCs) that will pinpoint the problem more accurately. This will provide far more specific direction than any generic troubleshooting guide.
Important Safety Note: Work on fuel systems involves flammable materials. Always disconnect the battery's negative terminal before starting any electrical work. Be cautious around fuel lines and components. If you are not comfortable working with automotive electrical systems, take your vehicle to a qualified mechanic.
