The ticking time bomb under the hood
Two of my friends had the Bosch CP4 high pressure fuel pump grenade in their 2012 F350s with the 6.7 liter Diesel. It took out the entire fuel system and injectors. Both trucks had over 130,000 mil...
Forum Discussion
covered wagon wrote:
I'm only familiar with Cummins. Does this injection pump being discussed have return fuel? Or is the fuel system returning fuel from each injector?
I ask because if the return fuel does come from both injectors and the injection pump, wouldn't it benefit by putting greater fuel flow, more volume and fuel pressure to increase return flow and thereby increase injection pump cooling?
My understanding is that it’s an issue with cavitation not cooling. It’s designed to not require a lift pump. This means the fuel that the cam lobe and bottom of the piston sit in is also the same fuel that is later pressurized and sent on the injectors. If there’s a fuel delivery problem between the tank and pump it can cause the piston/cam to cavitate and disintegrate and the pieces go everywhere downstream and unfiltered.
The bypass kit option someone built for it sends the lubrication fuel back to the tank and separately pressurizes other untouched fuel but requires a lift pump to push fuel toward it rather than it sucking fuel toward it.
There’s a good explanation with pictures here: https://www.drivingline.com/articles/new-product-spotlight-ss-diesel-motorsport-s-cp42-bypass-kit/
