1. Verify Relay and Fuse Replacement:
* Double-check the fuse: Make sure you're using the correct amperage fuse and that it's properly seated. Visually inspect it for any signs of damage even if it looks okay. A blown fuse can sometimes look fine.
* Relay testing: Even new relays can be faulty. Use a multimeter to test the relay's continuity and coil resistance. There are plenty of online videos showing how to properly test a relay. If you're not comfortable with this, have a mechanic check it. Also, try swapping the fuel pump relay with a known good relay from a different circuit (if safe to do so - some relays handle high amperage and should not be swapped) to see if the problem moves.
2. Trace the Wiring:
* Fuel pump relay wiring: Locate the fuel pump relay in the underhood fuse box. Trace the wires leading to and from the relay, carefully inspecting for any:
* Broken wires: Look for any cuts, chafing, or corrosion.
* Loose connections: Check all connectors for tightness.
* Corrosion: Clean any corroded connections with a wire brush and electrical contact cleaner.
* Power source to the relay: The relay gets power from the ignition system. Check the wire feeding power to the relay; it should have power when the ignition is on. A multimeter is essential here.
* Ground connection: The relay and the fuel pump need good ground connections. Check the ground wires for the fuel pump circuit for corrosion or loose connections.
3. Check the Inertia Switch:
The inertia switch (often located under the dash or in the engine bay) is a safety device that cuts power to the fuel pump in a collision. If it's tripped, it needs to be reset (usually a button to push).
4. Check the Fuel Pump Inertia Switch Circuit:
If the Inertia Switch seems fine, it's still worth checking the wiring to and from the switch. This can be another area where a break in the circuit could occur.
5. Consider the PCM (Powertrain Control Module):
While less likely, a problem with the PCM could prevent it from sending the signal to activate the fuel pump relay. This is a more advanced diagnostic step and usually requires specialized tools.
6. Professional Help:
If you've checked all the above and the problem persists, it's best to take your Z28 to a qualified mechanic. Troubleshooting fuel pump issues can be complex, and a professional with diagnostic tools will be able to pinpoint the exact cause much more efficiently. Ignoring a non-functional fuel pump could lead to engine damage.
