CP3 in Ram verses CP4 in Ford and GM

labren wrote:
Is there someone that could possible explain the difference in the cp3 system that is in a Ram verses the cp4 system that is in a Ford? The high pressure Fuel Pump, is it just a brand difference or an older version? Thanks for any input on this.

For the OP...here are some links from my archives on the topic. Learned
a lot from these threads

This one in particular to one of my Skunk Works at the Labs...we invented
diamond foam from CVD (chemical vapor deposition) diamond and is a
man made 'real diamond'...why DLC isn't really 'diamond', so named 'like diamond'...

NewsW wrote:
Posted: 02/10/12 09:54am

Just received confirmation from an expert in the field that Bosch may have overlooked something in the design and testing of the Bosch CP 4.x pump.

The pump is believed to use a Diamond Like Carbon Coating to lower friction and to withstand the intense pressure / temperature / wear.

While DLC coatings are normally believed to be inert and highly stable in automobile applications, research done in late 2007s suggest that the coating is not as inert / stable as originally believed.

This research was not public until late 2008, well after the design of the CP 4 pump was "frozen" and testing / validation done.

In fact, DLC coatings (tested in the above research) is now known to be reactive with common petroleum based lubricating oil additives.

It is highly likely that chemically similar compounds are found in diesel fuel normally sold in the USA.

Diesel fuel in the USA require considerably more refinery processing and use of additives to bring it "to spec" compared to European Spec Diesel fuel.

It is not just lubricity --- but chemical reactivity with DLC that is the prime suspect now in Bosch CP 4.x pump failures.


Bosch need to roll up their sleeves and get to work with some good science.


At present, we have a hypothesis.... not proven facts.



Side Note:

It is known that certain people will try to "home brew" fixes to the CP4 pump problem by adding lubricity additives (commercially sold or home made) to their diesel fuel. At least a few have publicly said they are doing so.

If this reseach is right... addition of lubricating oil (loaded with EXACTLY the stuff tested) in a vain attempt to improve "lubricity" of North American diesel will ACCELERATE, not RETARD the failure of the DLC coating (if it is similar to the one tested).

The poor jokers who have no background in petroleum chemistry, tribology, DLCs, etc. trying to "home brew" a fix for what is a very high tech, difficult to solve issue....

* This post was edited 02/10/12 10:05am by NewsW *

Note: I'm not a diesel guy, just a gear head, boy racer who loves
anything automotive. Almost went over, but decided the, then new
SMOG rules were going to be too onerous and a few years before they
settle down on what doesn't work to what does work

Here are the hot links for many days of reading up on this topic :B

Highly VOLATILE and opinions flew...but if you read past that...informative
Where NewsW and learned about each other. Smart guy...just too many
didn't like his style...we must have crossed paths many times during
our early careers...but never bumped into each other.


Ford 6.7 debacle just gets crazier


Warning...Warning...More Blue KoolAid needed ASAP


Ford HPFP vs. GM HPFP


More 6.7 Ford HPFP fun


2013 Rams using CP3 HPFP?


Anybody use the Motorcraft Cetane Booster?


2011 Ford Diesel


I think I stumbled upon some specs for the 2013 RAM HDs


Ford 6.0 Superduty


Another CP4 only this one is Canadian


Another case of dreaded 2011 Ford 6.7L HPFP failure?


Beware of Diesel Fuel Additives with DLC coated components


I'll ask again -anyone had any GM HPFP Fuel System Problems


Has YOUR Ford 6.7 Diesel HP Fuel Pump failed?


Ford PSD 6.7L


My Ford 6.0 PSD dead for good!


Ford Canada tells me to pound sand