The CP4 injection pump is the weak point of the 6.7L Cummins. A failure sends metal through the fuel system. The reliable fix is converting to the older, tougher CP3 pump.
engine
🚗 Dodge Ram 3500
Hard
How to Fix Dodge Ram 3500 CP4 Pump Failure
Red Rocket
·
August 7, 2026
·
⏱ 6-8 hours
·
2011-2019 Dodge Ram 3500
0
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Step-by-Step Instructions
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1
Confirm CP4 failure by checking fuel rail pressure and metal shavings in the filter.
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2
Disconnect the high-pressure fuel lines.
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3
Remove the failed CP4 pump.
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4
Install the CP3 conversion kit and new lift pump.
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5
Flush the entire fuel system to remove shavings.
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6
Prime, bleed, and test.
Tools & Parts Needed
- 🔧 CP4 to CP3 conversion kit, Fuel line wrench set, Diesel injector cleaner, Socket set
Frequently Asked Questions
How long does this fix take?
6-8 hours
Do I need special tools?
Yes — see the Tools & Parts list above.
Is this covered under warranty?
Check your vehicle warranty. Some repairs may be covered, especially if the issue is a known defect.
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