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2020 Ram 2500 Hemi No-Start Issue - Cranks but Won't Catch

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Paul Z. · rep 0 · May 22, 3:30 AM · 1 replies · solved · Question

Vehicle: 2020 Ram 2500 Laramie

My 2020 Ram 2500 Laramie with the 6.4L Hemi is giving me a headache. This morning, it just cranks and cranks but won't start. It was running fine yesterday, no warning lights or anything unusual.

I've checked the battery, it seems strong, and the starter is definitely engaging. It sounds like it's trying to turn over, but it just won't catch. I tried cycling the key a few times, but no luck.

Could this be a fuel pump issue, or maybe something electrical like a sensor? I don't have any codes showing on my basic OBD-II scanner. Any ideas on what I should check next?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:30 AM

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ClearTheCode admin answer:

A crank-no-start condition on your 2020 Ram 2500 6.4L Hemi can be frustrating, especially without any diagnostic trouble codes (DTCs). This usually points to a fundamental issue with either fuel, spark, or air, or a critical sensor preventing the engine from firing.

Here's a systematic approach to diagnose the problem:

  1. Check for Fuel Pressure: The most common cause for a crank-no-start without codes is a lack of fuel. Listen for the fuel pump priming sound (a low hum from the rear of the truck) when you turn the key to the 'ON' position (before cranking). If you don't hear it, check the fuel pump fuse and relay. A fuel pressure gauge can confirm if the pump is delivering adequate pressure to the fuel rail.
  2. Verify Spark: Remove one spark plug wire (or coil pack) and attach a spark tester, or carefully hold the plug near a grounded metal surface while someone cranks the engine (use insulated pliers). Look for a strong, blue spark. No spark could indicate issues with the crankshaft position sensor, camshaft position sensor, ignition coils, or the Powertrain Control Module (PCM).
  3. Check for Air/Compression: While less common for a sudden no-start, ensure the air intake isn't completely blocked. Compression issues are usually accompanied by other symptoms before a complete no-start.
  4. Sensor Input: Even without a code, a faulty crankshaft position sensor or camshaft position sensor can prevent the PCM from knowing when to fire the injectors and spark plugs, leading to a no-start. These sensors are crucial for engine timing.
  5. Security System: Ensure your vehicle's security system isn't engaged. Try using a different key if you have one, as a faulty transponder chip can sometimes prevent starting.

When to See a Shop:

  • If you've confirmed you have no fuel pressure and the fuse/relay are good, indicating a potential fuel pump failure.
  • If you have no spark and have checked basic ignition components.
  • If you suspect a faulty crankshaft or camshaft position sensor, as these can be tricky to diagnose without specialized tools.
  • If the issue persists after basic checks, as a professional can use advanced diagnostic equipment to pinpoint the exact cause, including checking for immobilizer issues or PCM faults.
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