L5P Duramax CP4 Failure and the CP3 Conversion That Fixes It
The 2017 and up L5P Duramax runs a CP4.2 pump that can grenade and take the whole fuel system with it. Here is the CP3 conversion...
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Tech guides
Diesel tech guides
What fails on Cummins, Power Stroke and Duramax trucks, why it happens, and the part that fixes it. Written by the people who do the work.
4 guides tagged Fuel System
Why Your Cummins Needs a FASS Lift Pump, and How to Pick One
The factory in-tank lift pump is the weak link feeding your injection pump. Here is what a FASS system actually does and how to size one...
Read the guideDuramax LML CP4 Failure and the CP3 Conversion That Fixes It
The 2011 to 2016 LML Duramax runs the same problem CP4 pump as the Ford. Here is why owners convert back to a CP3 and what...
Read the guideFord 6.7 Power Stroke CP4 Conversion: The Permanent Fix
A bypass kit limits the damage when a CP4 fails. A pump conversion removes the CP4 entirely. Here is the difference and when to step up...
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