* Faulty Fuel Pump Installation: The most common reason is incorrect installation of the new fuel pump. This could involve:
* Incorrect wiring: Double-check all wiring connections to the pump, ensuring they're secure and correctly matched. A reversed wire can fry the pump.
* Damaged pump assembly: The pump might have been damaged during installation (e.g., a cracked housing, bent float arm). Inspect the pump for physical damage.
* Incorrectly seated pump: The pump might not be seated properly in the tank, preventing it from drawing fuel or making proper contact with the sending unit.
* Fuel Pump Relay: The fuel pump relay might be faulty. A simple swap with another relay (of the same amperage) can help determine if this is the issue. (Consult your owner's manual for relay location and identification.)
* Fuel Pump Fuse: Check the fuse for the fuel pump. A blown fuse will prevent power from reaching the pump.
* In-tank Fuel Pump Filter (sock): Even with a new pump, a clogged or damaged in-tank fuel filter (the sock) can prevent fuel from reaching the pump. The filter is usually part of the fuel pump assembly and may need replacing along with the pump. If it's a separate part, this needs checking.
* Fuel Pump Control Module (PCM): In some cases, the PCM might be faulty and not sending the signal to activate the fuel pump. This is less common but possible. Diagnostics are needed here.
* Wiring Problems: Look for damaged or corroded wiring between the fuel pump, relay, and PCM. A break in the wiring will prevent power from reaching the pump.
* Clogged Fuel Filter (external): Though less likely to cause zero pressure, a severely clogged external fuel filter (the one that's outside of the tank) can restrict fuel flow.
* Bad Fuel Pressure Regulator: Though often associated with *high* fuel pressure problems, a faulty regulator can sometimes create unusual pressure scenarios.
Troubleshooting Steps:
1. Verify Fuel Pump Wiring: Reconnect the pump and carefully check all wiring for proper connections. Use a multimeter to check for power at the pump connector when the ignition is turned on.
2. Check the Fuel Pump Relay and Fuse: Test or replace these components.
3. Check the Fuel Filter (sock and external): Replace if necessary.
4. Listen for the fuel pump: When you turn the ignition key to the "on" position (without cranking the engine), you should hear a brief humming sound from the fuel pump. If you don't, this indicates a problem with power reaching the pump.
If you've checked all these points and still have no fuel pressure, you'll likely need a professional mechanic with diagnostic tools to pinpoint the exact issue. They can check the PCM and other less easily accessible components. Don't keep cranking the engine with no fuel, as this can cause further damage.
