Replacing your fuel filters is essential maintenance for the Ram 2500 with the 6.7 Cummins engine, but many owners experience a frustrating issue: the truck cranks long, struggles to start, or won’t start at all right after installing new filters. This guide explains why and how to fix it.
Why Your Ram Struggles to Start After a Filter Change
1. Air in the Fuel System
The most common cause of start-up problems after a filter change is trapped air. When filters are swapped, air can enter the fuel lines and prevent steady fuel delivery to the injectors. Without consistent fuel pressure, the engine will crank but struggle to fire or may stall shortly after starting.
2. Improper Filter Installation
Even a slightly misaligned filter or a loose seal can cause pressure loss or fuel leaks. The dual-filter arrangement on the Ram 2500 is sensitive to correct seating—so always confirm both filters are properly fitted and tightened.
3. Using Non-OEM Filters
Aftermarket or low-quality filters may save money up front but often cause fitment issues, leaks, or priming problems. For the 6.7 Cummins, using genuine parts—such as the 68157291AA Mopar fuel filter—helps avoid compatibility issues with factory sensors and fittings.
4. Sensor & Pressure Issues
Your Ram’s fuel system includes sensors that monitor pressure and water-in-fuel levels. During priming, these sensors can detect irregular flow and temporarily prevent normal starting until the system stabilises. Corroded connectors or wiring near the sensors can also complicate the issue.
How to Fix Starting Problems After a Filter Change
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Prime the Fuel System Correctly
Cycle the ignition key several times (without starting) to activate the in-tank lift pump and push fuel through the lines. If your truck has a manual primer, use it until it feels firm. This removes air pockets and restores proper fuel pressure. -
Double-Check Installation
Inspect both filter housings, seals, and clamps. Make sure the 6.7 Cummins filters are seated correctly and fittings are tight to prevent leaks or air ingress. -
Drain and Recheck for Water
Ensure the water separator is fully drained. Residual water can trigger warnings and impair fuel delivery. -
Use Genuine Mopar Filters
Stick with OEM parts like the 68157291AA. A proper Mopar fuel filter is engineered to fit and perform with factory sensors and pump demands. -
Be Patient With First Start
It’s normal for the engine to crank a little longer immediately after a fresh filter install. Once the air clears and pressure stabilises, the truck should start and run normally.
Preventing Future Issues
To avoid starting problems after future filter changes, follow these simple best practices:
- Replace fuel filters at recommended intervals (commonly every 15,000 miles for heavy-duty diesel applications) or sooner in harsh conditions.
- Drain the water separator regularly, especially when refuelling at unfamiliar or low-quality fuel stations.
- Always prime the system thoroughly after replacement and check for air leaks.
- Use genuine OEM 6.7 Cummins filters to ensure correct fit and long-term reliability.
Why Mopar OEM Filters Are the Best Choice
Choosing the right filter is about more than convenience—it’s about protecting your engine. Mopar fuel filters are designed to meet strict factory standards: precise fitment, reliable water separation, and particle filtration to protect injectors and pumps. The 68157291AA is a direct-fit OEM option built for the demands of the 6.7 Cummins.
Final Thoughts
If your Ram 2500 struggles to start after a fuel filter change, the issue is usually temporary and related to trapped air or installation errors. By priming the system correctly, using genuine Mopar filters, and confirming proper fitment of your 6.7 Cummins filters, you’ll eliminate most starter headaches and keep your truck running reliably.
Shop Mopar fuel filters, including part 68157291AA, to protect your Cummins engine and ensure long-lasting performance.
