Symptoms:
* No cranking: You might not hear the fuel pump prime (a brief whirring sound) when you turn the ignition key to the "on" position (before cranking).
* Cranking but no start: The engine cranks (turns over), but won't fire up because there's no fuel being delivered to the combustion chambers.
Possible Causes:
The lack of power to the fuel pump can stem from several issues:
* Blown fuse: Check the fuse box (usually under the hood and/or inside the vehicle) for a blown fuse related to the fuel pump. Your owner's manual will show you which fuse is responsible.
* Relay failure: The fuel pump is often controlled by a relay. A faulty relay will prevent power from reaching the pump. Locate the fuel pump relay (again, consult your owner's manual) and try swapping it with a known good relay of the same amperage.
* Wiring problems: A broken or corroded wire in the circuit leading to the fuel pump can interrupt the power supply. This requires visual inspection of the wiring harness, particularly around the fuel pump itself (located in the fuel tank). This is the most difficult to diagnose and requires some electrical knowledge and potentially a multimeter to test continuity.
* Fuel pump inertia switch: Some vehicles have an inertia switch that cuts power to the fuel pump in the event of a collision. This switch is usually located in the passenger compartment (check your owner's manual for its location). If it's tripped, reset it.
* Faulty fuel pump: While less likely to be the direct cause of *no power*, a completely failed fuel pump could have shorted out and blown a fuse, or damaged wiring. Testing the pump itself requires a little more advanced diagnostics, often needing to access and test it directly at the pump connector.
* PCM (Powertrain Control Module) issue: In rare cases, a problem with the PCM (computer) could prevent it from sending power to the fuel pump. This usually results in other symptoms as well.
Troubleshooting Steps:
1. Check the fuses: This is the easiest and quickest check.
2. Check and reset the inertia switch (if equipped): This is a simple fix if the switch is the culprit.
3. Check the fuel pump relay: Swap it with a known good relay.
4. Visually inspect the wiring: Look for any obvious damage, corrosion, or loose connections in the wiring harness leading to the fuel pump.
5. Use a multimeter (if you have one): Test for power at the fuel pump connector. This requires some basic electrical knowledge and safety precautions.
Important Note: Working with fuel systems requires caution. Fuel is flammable, and working near the fuel tank and pump carries inherent risks. If you're not comfortable performing these checks yourself, take your Suburban to a qualified mechanic. Improperly diagnosing and repairing fuel system issues can be dangerous.
