1. Fuel Delivery:
* Empty Tank (Obvious but important): Seriously, check your fuel gauge.
* Fuel Pump: The pump might have failed. You might hear the pump prime when you turn the key to the "on" position (before cranking). Listen carefully. If you don't hear a whirring sound, the fuel pump is suspect.
* Fuel Filter: A clogged fuel filter can restrict fuel flow. This is relatively inexpensive to replace.
* Fuel Injectors: While less likely to suddenly fail *all* at once, a problem with the injectors could prevent fuel from reaching the engine. This is harder to diagnose without tools.
2. Ignition System:
* Spark Plugs and Wires: Worn or damaged spark plugs or wires can prevent ignition. Check for cracks or corrosion on the plugs and wires.
* Distributor Cap and Rotor: Inside the distributor, the cap and rotor distribute the high voltage to the spark plugs. Cracks or corrosion here can interrupt the spark.
* Ignition Coil: The coil generates the high voltage for the spark plugs. A faulty coil will prevent sparking. This usually requires testing with a multimeter or other diagnostic tool.
* Ignition Module (or Control Module): This is the electronic "brains" of the ignition system. Failure here can be difficult to diagnose without specialized equipment. (More common on older vehicles.)
* Cranking Sensor/Cam Sensor: These sensors tell the computer when the engine is turning over, and if they fail the computer won't provide the spark.
3. Battery and Electrical System:
* Battery Terminals: Corroded battery terminals can prevent sufficient current flow. Clean them with a wire brush.
* Battery Voltage: A weak battery might crank the engine slowly, preventing it from starting. Test the battery voltage with a multimeter.
* Alternator: While less likely to be the sole cause of a no-start (unless the battery was already weak), a bad alternator can't recharge the battery, leaving you stranded.
4. Other Possibilities:
* Security System (if equipped): If your Suburban has an aftermarket or factory alarm system, it could be interfering.
* Neutral Safety Switch: This prevents the engine from starting unless the transmission is in park or neutral. If it's faulty, the starter might crank but the engine won't fire.
* Sensor Problems: Other sensors (like the crankshaft position sensor or oxygen sensor) can prevent the engine from starting. But this is less likely to be the sudden cause of a no-start.
Troubleshooting Steps:
1. Start with the easy stuff: Check the fuel level, battery terminals, and listen for the fuel pump.
2. Visual Inspection: Look for obvious problems like loose wires, broken components, or signs of damage.
3. Check for Spark: You might need a spark tester to verify spark at the spark plugs.
4. Get a multimeter: This will allow you to test battery voltage, and possibly the ignition coil and other components.
5. Consider a professional mechanic: If you're not comfortable working on your vehicle's electrical system, a mechanic can diagnose the problem accurately.
This is a lot of information, but hopefully it gives you a good starting point. Systematically checking these areas should help you find the problem. Remember safety first – disconnect the negative battery terminal before working on the electrical system.
