1. Verify the Basics:
* Fuel: Does the fuel pump prime when you turn the key to the "on" position (but before cranking)? You should hear a brief whirring sound. If not, you might have a fuel pump issue, a blown fuse, or a bad fuel pump relay. Check your fuel pressure as well. A low fuel level is also a possibility!
* Spark: Even with new parts, you need to *confirm* you have spark at the spark plugs. Use an inline spark tester or a good quality spark plug wire tester. If you don't have spark, the problem is likely in the ignition system beyond the distributor (coil, ignition module, etc.).
* Timing: Did you check the distributor's timing after installation? Improper timing can prevent the engine from starting, even with spark and fuel. This often requires a timing light.
* Battery: Is the battery fully charged and the connections clean and tight? A weak battery can easily prevent a start.
* Starter: Does the starter motor crank the engine over strongly? A weak or failing starter will only result in a slow crank. If it's cranking, it may not be the problem, but if not, you have a new issue.
2. Ignition System Diagnostics (if no spark):
* Ignition Coil: A failing ignition coil is a common cause of no spark. Test the coil's primary and secondary resistance using a multimeter to see if it's within specifications (look up specs for your specific year/engine).
* Ignition Module (or Control Module): These modules control the ignition coil. A faulty module will prevent spark. Testing often requires a multimeter and a knowledge of the specific module's wiring. These are not always easily testable without a professional-grade scan tool.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational position. A faulty CKP prevents proper spark timing.
* Camshaft Position Sensor (CMP): Similar to the CKP, but monitors the camshaft.
3. Other Possibilities:
* Security System: Does your Suburban have an aftermarket or factory alarm/immobilizer system? A malfunctioning system can prevent starting.
* Neutral Safety Switch: The automatic transmission needs to be in Park or Neutral for the starter to engage. Check this switch and it's wiring.
* PCV Valve: A severely clogged PCV valve can create issues in the crankcase resulting in poor performance or lack of starting.
4. Seeking Help:
If you're not comfortable working on these more advanced diagnostics, it's best to take the Suburban to a qualified mechanic. Trying to troubleshoot electrical issues without proper tools and knowledge can lead to further damage.
Remember to always disconnect the negative battery terminal before working on any electrical components. Safety first!
