If you're having ignition issues, the problem isn't the firing order itself but something *affecting* the firing order's execution. Here are some possibilities and troubleshooting steps:
* Worn or faulty spark plugs/wires: This is the most common cause of misfires. Inspect the plugs and wires for damage, wear, or cracks. Replace any that are questionable.
* Bad ignition coil(s): The Hemi uses individual coils for each spark plug. A faulty coil will prevent the correct cylinder from firing. Testing with a multimeter or using a professional-grade scan tool is necessary to diagnose bad coils.
* Distributor cap and rotor (if applicable): The 5.7 Hemi doesn't use a distributor; it's a coil-on-plug (COP) system. This step is irrelevant for this engine.
* Faulty crankshaft position sensor (CKP): This sensor tells the computer the engine's rotational position, which is crucial for proper firing order sequencing. A bad CKP will cause major ignition problems. A scan tool can often identify a bad CKP sensor.
* Faulty camshaft position sensor (CMP): Similar to the CKP sensor, this one provides information about the camshaft's position. Problems here can also disrupt the firing order. A scan tool can often identify a bad CMP sensor.
* Wiring issues: Check for damaged, corroded, or loose wiring related to the ignition system.
* PCM (Powertrain Control Module) problems: In rare cases, a faulty PCM can cause ignition problems. This is usually diagnosed by a professional mechanic using a scan tool.
* Fuel delivery problems: While not directly related to firing order, fuel delivery issues can cause misfires that might *seem* like a firing order problem. Check fuel pressure and injector operation if other ignition components are fine.
How to use the firing order:
The firing order is essential when you're:
* Replacing spark plugs or wires: Ensuring they're installed in the correct order is crucial for proper engine operation.
* Diagnosing misfires: Understanding the firing order helps determine which cylinder is misfiring. A scan tool will usually identify the misfiring cylinder, making this step less critical.
If you're experiencing ignition problems, start with the simplest checks (spark plugs and wires), then move to more complex diagnostics (coils, sensors). If you're not comfortable working on your vehicle's ignition system, consult a qualified mechanic. Improperly diagnosing and repairing ignition issues can cause engine damage.
