Just read good article detailing how the CP4 injector pumps on Duramax, Ford and Dodge trucks are going to fail due to pump not being compatible with American diesel fuel. This is becoming a large problem in these trucks that hits the owners for several thousands dollars. There is a major class action lawsuit over the issue. Attached are a couple of links. Hope this helps someone who has had the problem.

https://www.carcomplaints.com/news/2018/bosch-cp4-fuel-pump-failures-lawsuit.shtml

https://www.carcomplaints.com/news/2018/bosch-cp4-fuel-pump-failures-lawsuit.shtml

Here is a link that I read on the subject. If you have a truck with a CP4 injector pump you better beware, your time is coming. Had a friend with a Duramax recently paid $8000 for his fuel system to be repaired.

https://www.dieseltechmag.com/2017/12/common-problems-the-cp4-time

I know dozens of people with diesel trucks and only read about this on the forums. It's far from a sure thing and most happen on higher mileage trucks. Sucks that it takes the fuel system down when it happens though. If you search cp4 bypass they make a kit that bypasses the lubricating fuel back to the tank so if the pump dies it won't take out your fuel system.

No filter between the pump and injectors such as on practically every gasoline engine?

The Cummins engines still have the CP3

MouthBQ98 said:

---

No filter between the pump and injectors such as on practically every gasoline engine?

---

Not a whole lot of filters for that high of pressure, the bypass kit solves the problem(well at least protects in case of failure) and should have been that way from the factory.

The CP4 is a high pressure fuel injection pump, mounted in the engine bay, which directly feeds high pressure to the common rail and draws fuel from the tank. As a fact, the CP4 will destroy the entire fuel system of 100% of the trucks it is installed in. It is in Ford 6.7L PowerStroke engines from 2011 to present and GM 6.6L Duramax LML Diesel engines from 2011 to 2016, 3.0 L EcoDiesel Jeep Cherokees and Ram trucks, and various ambulances, delivery vans, and other vehicles. The CP4 was a cost saving measure, using fewer parts and less fuel, replacing the very reliable CP3.

If I had a pre '17 Duramax with the CP4 I'd do the CP3 conversion. About $3K. GM fixed the issue with the '17 and up L5P. They went to a Denso HPFP and a lift pump in the tank.

VW had the same issue with the Bosch HPFP. Issues can be traced back to USLD requirement. This is really what drives all the fuel additive threads on any number of forums. Do we need something to add lubricity?

Whew. I was nervous for a minute until I saw they fixed this on the L5P.

Adding a lift pump on my 2016 Duramax with the delete. The issue with the CP4 is that it pulls the vacuum for the fuel from the tank and well as supplying fuel to the high pressure injectors. With the lift pump you lower the possibility of failure in the CP4.

Quote:

---

GM fixed the issue with the '17 and up L5P

---

Is there a way of knowing whether your truck has it? Are all 2017s and newer safe? Daughter has a 2017 that had the turbo go out, would like to help her prevent this disaster.

Every single CP4 is starved of lubrication and results in metal rubing against metal in a highly pressurized environment, without lubrication--as a result the CP4 starts to shed tiny pieces of metal shards almost immediately, sometimes as early as mile one. By a hundred thousand miles, all truck owners see the costly results. Their engines self-destruct, the CP4 disintegrates and sends thousands of metal shards into the fuel injection system and every part of the engineresulting in $8,000-$20,000 worth of repairs.

GM has changed the pump for MY17 as stated above, not sure if ford has yet.

OP - Thanks for posting about this. I'm surprised I haven't already read it on here (maybe I missed it).

My thanks, too. Daughter's turns out to be a 2015. Have forwarded info to she and her husband. Her brother-in-law is a diesel mechanic (industrial engines) and maybe he can help them make some decisions.

CanyonAg77, read the LML section of duramaxforum. https://www.duramaxforum.com/forum/11-16-lml-duramax-powertrain/

Probably lots of threads on the subject.

The following vehicles may be affected:

• 2011-2016 Ford diesel pickups, including the F-250, F-350, and F-450 (6.7L Power Stroke engines)
• 2011-2016 Chevrolet Silverado diesel trucks (Duramax LML engine)
• 2011-2012 Chevrolet Silverado diesel trucks (Duramax LGH engine)
• 2011-2016 GMC Sierra diesel trucks (Duramax LML engine)
• 2011-2012 GMC Sierra diesel trucks (Duramax LGH engine)
• 2010-2011 GMC Savana (Duramax LGH engine)
• 2010-2011 Chevrolet Express van (Duramax LGH engine)
• 2014-2016 Jeep Grand Cherokees (EcoDiesel engine)
• 2014-2016 Dodge Ram trucks (EcoDiesel Engines)

I have a 15 f250

What's the fix?

jefe95 said:

---

I have a 15 f250

What's the fix?

---

Seconded on this question.

jefe95 said:

---

I have a 15 f250

What's the fix?

---

Lift pump and bypass kit should do it, if this is even a real problem.

bypass kits are about 350 for f250 and I've thought about it, but I'm under extended warranty to 100K and don't want to void it. While there isn't alot to install it it does involve taking a few things apart/grinding to install.

I wonder how often this really happens? When I had a TDI Touareg the boards were full of threads about Bosch HPFP failure, but very, very few posts from anyone that actually had it happen.

Does Texas still have a mandate for 50 cetane value diesel? That was achieved many times with a bio diesel blend. Nothing increases lubricity in #2 diesel like a splash of bio.

Take it with a grain of salt (article as written in 2007) but it seems to be pretty interesting from Diesel Place. Looks like 2% biodiesel would be the way to go if available to increase longevity of the CP4.

Unfortunately i don't have a place near me for biodiesel, so i think I am going to try the Opti-Lube XDP and see how it shakes out. The product claims an 8 oz bottle treats 32 gallons, but the results of the test state that 13oz per 26 gallon tank was required to get the fuel to the proper lubrication ratio.

Lubricity Additive Study for Diesel Vehicles

From the article:

Quote:

---

How Diesel Fuel Is Evaluated For Lubricating Ability:

Diesel fuel and other fluids are tested for lubricating ability using a device called a "High Frequency Reciprocating Rig" or HFRR. The HFRR is currently the Internationally accepted, standardized method to evaluate fluids for lubricating ability. It uses a ball bearing that reciprocates or moves back and forth on a metal surface at a very high frequency for a duration of 90 minutes. The machine does this while the ball bearing and metal surface are immersed in the test fluid (in this case, treated diesel fuel). At the end of the test the ball bearing is examined under a microscope and the "wear scar" on the ball bearing is measured in microns. The larger the wear scar, the poorer the lubricating ability of the fluid. Southwest Research runs every sample twice and averages the size of the wear scar.
The U.S. standard for diesel fuel says a commercially available diesel fuel should produce a wear scar of no greater than 520 microns. The Engine Manufacturers Association had requested a standard of a wear scar no greater than 460 microns, typical of the pre-ULSD fuels. Most experts agree that a 520 micron standard is adequate, but also that the lower the wear scar (HFRR) the better.

THE RESULTS:

These results are listed in the order of performance in the HFRR test. The baseline fuel used in every test started at an HFRR score of 636. The score shown is the tested HFRR score of the baseline fuel/additive blend.

In Order Of Performance:

1) 2% REG SoyPower biodiesel
HFRR 221, 415 micron improvement.
50:1 ratio of baseline fuel to 100% biodiesel
66.56 oz. of 100% biodiesel per 26 gallons of diesel fuel
Price: market value

2)Opti-Lube XPD
Multi-purpose + anti-gel
cetane improver, demulsifier
HFRR 317, 319 micron improvement.
256:1 ratio
13 oz/tank
$4.35/tank

3)FPPF RV, Bus, SUV Diesel/Gas fuel treatment
Gas and Diesel
cetane improver, emulsifier
HFRR 439, 197 micron improvement
640:1 ratio
5.2 oz/tank
$2.60/tank

---

As you said, that's an old test. Some of the products are no longer on the market and others may have been reformulated since then. No way to tell. Opti-Lube drew lots of criticism as it was the only product in the test not purchased over the counter. It was supplied by the manufacturer. Opti-Lube claims to still be the leader on lubricity, but their test is in house. Test should have been done by a reputable lab to be valid.

Lots of people use it, but as with any additive there is no way to quantify how well it works without lab testing. There's a well thought of poster on BITOG that's a chemist who formulated FPPlus and Corrosion X. I asked him once for his opinion based on the MSDS and he thought it to be an unremarkable blend of solvents. He also pointed out there is as much to learn from what is not listed in the MSDS as what is listed.

I used an additive for 175,000 miles on the TDI and I use one in the Duramax. I've tried to select for combustion chamber and injector cleaning ability as I think that is more of an issue than just lubricity.

The CP4 housing is cast , Not harden steel like most CP3s, the CP4 is much cheaper to manufacture, it weights in at 8.2 LBS, All CP3 GM or Ram weight in at 19LBS, I have R/RP CP3 with 700K still running Strong after being freshen up, all CP3s are million mile pumps if freshen up at 250/300K, the CP4 is a throw away pump. I have seen many CP4s with 100K that are near death, I do like the roller sleeves in all CP4s, but thats about it. I have yet to see 200K form any CP4.they be out there I just have not seen one.

What pump does a 6.4 powerstroke have (08-10 F250)?

In house motor craft branded I believe

Do the 2019 Ferd's still use the CP4?

From what I'm reading on the Diesel Power Products website, yes.

Corps_Ag12 said:

---

From what I'm reading on the Diesel Power Products website, yes.

---

Guess I'm going to wait for a 2020 Chevy/GMC then.

HumbleAg04 said:

---

Corps_Ag12 said:

---

From what I'm reading on the Diesel Power Products website, yes.

---

Guess I'm going to wait for a 2020 Chevy/GMC then.

---

GM fixed this in the 2017s.

WP69 said:

---

HumbleAg04 said:

---

Corps_Ag12 said:

---

From what I'm reading on the Diesel Power Products website, yes.

---

Guess I'm going to wait for a 2020 Chevy/GMC then.

---

GM fixed this in the 2017s.

---

Yeah but I want to see the redesign and knowing they moved the def tank peaked my interest.

I might just taking a smoking deal on a '19 as the new 20s hit the lot.

Long thread here...
https://www.duramaxdiesels.com/forum/showthread.php?t=59976

Even longer thread here from TDI Club....
http://forums.tdiclub.com/showthread.php?t=299854

Here is good article on problems of Duramax LML/LGH CP4 Pump Failure.

https://www.injectorsdirect.com/duramax-lml-lgh-cp4-pump-failure-technical-bulletin/