2021 Ram 3500 H.O.

ShinerBock wrote:
I will say that the Denso HP3 and HP4 pumps are not without their flaws either. We have had some failures on them as well in the Hino(Toyota) medium duty diesel trucks. There are even a few TSB's out for them. The reason why most probably don't here about them is because Denso does not have that big of a market share especially in the personal vehicle market. Even on the commercial side, diesels powered by Denso fuel systems is very small.

I think people need to understand that these pumps are pumping at very high pressures. Just as with horsepower, the higher you go, the likelihood of component failure increases as well. For all you wanting and bragging about more stock short burst power, this is what you get because the manufacturers have to increase pressure every time they have a major power increase in order to stay emissions legal. You can't have your cake and eat it too. As with VG turbos and other components, you are starting to sacrifice reliability for the pursuit of more power on engines that also have to meet emissions.

Hence the reason why I would rather the engine makes have lower power, but use more reliable parts. I can easily add power after the fact that will make the truck more reliable by ditching things like electronically controlled VG turbos and so on that are less reliable than their mechanical counterparts.

It seems as though when they go lower power they use a smaller block and then the same VG turbos and CP 4.2 pumps anyway. I think someone offers a kit to put a CP3 on the new Cummins that doesn't require any tuning. They must do something to the pump to boost the pressure to the identical level that the CP4 is running..... Wouldn't you think Bosch would have gone that route instead of changing to the CP4.2. Even the aftermarket bypass kit that is offered for the Duramax and Ford would put people's minds at ease and seems as though it could be done for a very reasonable cost at the factory. (Aftermarket is expensive but what would it cost Bosch to add something like that to their fuel system ... $30?)