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Conversion Kits

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Conversion Kits

For Duramax owners who have CP4 fuel systems that have not malfunctioned, you may be on borrowed time. When the CP4 was introduced as the CP3 replacement, it was great for manufacturers, but over time, proved to be a poorly built component that could kill a whole fuel system. To remedy the issue and to act as preventative maintenance, many Duramax owners are converting back to CP3 systems for better reliability and performance. Merchant Automotive is going to have everything you need for your CP3 Conversion in an all-in-one-kit.

What Year Duramax Had CP4 Problems?

If you have been around the Duramax scene, you have most likely heard of the complaints of the CP4 fuel injection pump complaints. The CP4 pump replaced the older CP3 pump, but many are converting back to the CP3 with conversion kits for the efficiency of the CP3. Duramax trucks from 2011-2016 had CP4 fuel injection pump issues. The CP3 pump was used for most 2001-2010 Duramax engines, and even some 2003-2018 Cummin diesel engines. Most failing CP4s will present problems around 100,000 miles and will usually destroy the entire fuel system. This means you will be looking at replacing most of the components in your fuel system, costing you thousands of dollars.

CP3 Vs CP4

The early Duramax trucks used a CP3 style fuel injection pump that was pretty reliable and never really had any issues other than failure from old age. Over time, the CP3 was phased out for the CP4 unit as it was a lower cost and lighter compared to the CP3. As years progressed, Duramax owners noticed that there were far more problems with the CP4 when compared to the CP3. CP4 failure was causing catastrophic failure to Duramax fuel systems, resulting in repairs up to $10,000. This caused manufacturers such as Merchant Automotive to develop CP4 to CP3 conversion kits to remove your CP4 pump and install a brand new CP3 pump for better performance and reliability.

What Do I Need To Convert From A CP4 To A CP3 Fuel Pump?

Catastrophic failure on CP4 fuel injection pumps on 2011-2016 LML Duramax trucks will send small metallic debris throughout the entire fuel system. Our CP3 conversion kit will allow you to replace your less-reliable CP4 fuel injector pump before you experience catastrophic failure. This kit can also be used if you have a failed pump that did not destroy your fuel rails or injectors. For those who did experience complete failure and need to replace the fuel rails and injectors, check out our complete CP4 fuel system replacement kit.

This CP3 conversion kit includes a new S&S modified CP3 fuel injection pump, fuel lines, and the install kit to get your CP4 converted to a CP3 injector pump. This kit requires no tuning and is EPA approved. The CP3 pump is already re-calibrated to match the LML stock CP4 fuel curve. This kit is designed to replace the less reliable CP4 that comes stock on the LML.