Ford guys are not the only ones stuck with the CP4. The 2011 to 2016 LML Duramax runs the same style high pressure pump, and it fails the same expensive way. When a CP4 comes apart, it pumps metal debris through the entire fuel system, and on the LML that means a repair bill that can run well into five figures by the time you replace everything it contaminated.
The good news is the fix on these trucks is proven and clean. You convert back to the CP3.
Why the CP3 Conversion
- The CP3 is the older pump and it is far more durable than the CP4
- It is tolerant of our fuel, which is what kills CP4 pumps
- It flows plenty for stock power and supports more when you build
- Once it is on, the number one fuel system failure on the truck is gone
What the Kit Does
The S&S LML Duramax CP3 Conversion Kit swaps the failure prone CP4.2 for a CP3 with the hardware to make it work as a clean, complete conversion. It is the same logic we apply on the Ford 6.7 CP4 conversion. Take the weak pump off the truck instead of waiting for it to take the fuel system out.
Do It Before It Fails
A CP4 conversion is a lot cheaper than a CP4 failure. If you are running an LML and still on the factory pump, this is the upgrade that buys you peace of mind and protects everything downstream of it.