Why does my CP4 pump fail?

This may be due to the CP4 pump failing. Your CP4 pump is your high-pressure fuel pump. This pump converts low fuel pressure into high fuel pressure. Your CP4 may fail due to many reasons. 


The CP4 pump may fail due a lack of lubrication to the pump itself. This lack of lubrication can be from ultra-low sulfur diesel. This diesel does not have all the lubrication properties that are needed for the pump to work correctly. It can also fail due to water in your fuel system. The water will take away the lubrication properties of your diesel and this will cause the pump to fail. Water in your fuel can cause failure. Your fuel filters help to filter out the water. If you fuel filters are old, then they will not filter out the water properly. 

Your CP4 pump has a camshaft with lobes inside the pump. When this component starts to fail it causes metal debris. This debris is introduced into the fueling system including your fuel injectors, fuel tank, fuel lines, anything that fuel goes through. 



This failure cannot be prevented. We can contain the damage to just the pump itself. By doing this we prevent it from damaging your fuel injectors, fuel tank, fuel lines and all the other components. To do this we need to install a disaster prevention kit. This kit filters and re-routes the fuel. It lessens the repairs that are needed to keep you on the road. 


Give us a call and let us take care of you. 


Happy Adventures, 


Heather

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By jhautoinc February 3, 2026
You want this to work properly.
By jhautoinc January 30, 2026
These are vital to keep you safe on the road.
By jhautoinc January 27, 2026
Your engine will thank you.
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They help keep your engine cool.
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They need maintenance to keep them running.
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It's better for your engine. 
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They are more important than you know.
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A spark plug gap can cause a misfire.
By Bobby Poist January 7, 2026
They're important to keep you safe on the road.
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It's more often than you think.