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Discussion Starter #1
While the Cummins 5.0 is the obvious star of the new Titan XD, I'm still a little weary of the Bosch high pressure fuel pump on this engine.


Here's my story:


-A few years ago I bought a brand new MK5 Jetta 2.0 TDI highline - awesome car!
-At about 10,000 km the secondary fuel pump (boost pump) that feeds the HPFP started making a grinding noise, and was getting more prominent rather quickly. Searching online forums, people were just starting to complain of fuel pump failures and metal particles contaminating the fuel system. Naturally I checked the fuel filter and...could see glitter (see pic). Off to the dealer I went and they quickly and quietly changed out the boost pump. I quizzed about metal particles and CP4.1 HPFP failures - they of course denied anything and everything.
-At around 15,000 km the lift pump in the tank started making noise, and of course was getting increasingly noisy rather quickly. I checked the filter again, finding more glitter than the first time. Back to the dealer again. They replaced the lift pump and sent me on my way.
-After 2 out of the 3 pumps failed I started monitoring the fuel filter more frequently. At around 22,000 km there again was glitter in the fuel filter, and also on the pressure regulator plunger.
-I changed the filter and sold the car shortly thereafter. The thought of having to go through a full fuel system replacement (to the tune of $10k) was just too scary.
-The engine ran fine and gave no indication of deterioration or impending failure.
-Not once did anybody but myself put fuel in that car. I always used top tier diesel, either Shell or Coop EP3000. Besides, Canadian diesel is spec'd to have a higher lubricity rating, which the CP4 pump requires
-The Jetta was one of the better vehicles I've had to date and I still miss it. 58 mpg all day long! How can you argue with that!


Now, here is where my concern comes in - the Cummins ISV 5.0 uses the same Bosch pump as the VW 2.0 TDI...the only difference being another piston (hence the 4.2 designation). Ford 6.7 and GM 6.6 diesels also use this pump and it's well known that they have experienced failures as well. GM has been better at keeping those on the down-low compared to Ford. Ram 6.7 is still using the tried and true CP3 pump.


I'm sure that Cummins has tested everything to the nines...but I still have reservations about this CP4 pump. Does anyone know if Bosch has finally corrected this issue and improved the durability of the CP4 pump? It's such a fragile thing...!
 

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Ford claims to have a modified version of the pump in their 2015 Superduties.
But who knows whether that really fixes the problem.

Seems to me that the pump problems could be mostly stopped with proper pre-treatment: filtering, de-watering and so on. Think Cummins has always been strong in that area. Not sure what the 5L has though.
 

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Also I read that GM is dropping Bosch completely from their new model 2017 Duramax diesels.

And I hear you about the VW. There was a lot upset people on the TDI Club forum when those fuel pump problems started.

Our 2005 Passat had an older engine. No fuel pump issues but I did have to replace the chain driven oil pump with a gear driven one for Can$3500. Still going strong now though up in Prince George, B.C.
 

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Discussion Starter #5
Also I read that GM is dropping Bosch completely from their new model 2017 Duramax diesels.


Correct - GM is moving to a Denso fuel system for the 2017 HD powertrain refresh, which it badly needs.


Duramax = Isuzu = Japanese
Denso = Japanese


...see a trend? Lol.


The thing to realize here is the forthcoming diesel war between the light truck manufacturers. Here is a quick breakdown:


GM Duramax
-6.6L V8
-2.8L I4
-planned (but not confirmed) 4.5L v8


Ford PowerStroke
-6.7L v8
-3.2L I5


Ram
-6.7L I6 Cummins
-3.0L v6 VM Motori


Nissan
-5.0L v8 Cummins
-2.8L I4 Cummins


Toyota
-??


Obviously Nissan is aware of this lucrative market opportunity, and are placing themselves nicely into it (albeit too slowly). Regardless, I salute them for doing it. The whole David vs Goliath mentality. However, only Ram and Nissan have the Cummins brand, which means a heck of lot more than "proprietary" self-generated so-called brand names from GM and Ford. No offense.


The brand "Cummins" has impact. It has value-added characteristics. It has heritage. It's world renown. It just plain sells trucks! Why do you think I'm here on this forum!


ok, off my soap box for now.
 

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Is Nissan really going to put the 2.8L Cummins in their Frontier?
Wonder how that would compare to the Duramax in the Canyon.
That would be quite a shoot out.

There's also rumours that Ford is bringing its Ranger and (Gasp!) the Bronco back.
I bet they drop one of their I4 diesels in there too.

Almost makes me want to get a smaller trailer.
 

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2019 Titan XD Pro4x Cummins
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GM was talking about using Delphi a few years ago.

Bosch is pretty much number one in the world and years ago a Denso pump was just a licensed bosch pump.

I don't know how true it is but I read once that the biggest reason for CP4.2 issues is gasoline contamination.
 

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GM was talking about using Delphi a few years ago.

Bosch is pretty much number one in the world and years ago a Denso pump was just a licensed bosch pump.

I don't know how true it is but I read once that the biggest reason for CP4.2 issues is gasoline contamination.
Water contamination because people don't know they are getting junk fuel. The whole fuel systems in diesels are extremely sensitive to water.
 

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Discussion Starter #12
All good points. Fuel quality and vendor is always a concern, but it's usually the first excuse and attack strategy used by the manufacturer in the event of a failure. The reality is, the cp4 pump sucks. It does not have a robust design, hence the reason I started this thread. I'm just hoping that Cummins made some kind of improvement. Would be nice to know...
 

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The CP4.2 failures are more common in North America than Europe. That would lead a person to believe the failures are related to poor fuel quality, consistancy, contamination and user error.

So instead of accusing the pump of being a flawed design, which it's not, look at the real problem, North American apathy.
 

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The diesel we export to EU is clear like water there are so few impurities. Only place on earth where we sell the good stuff off at bargain prices and keep the crap for our own people.
 

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Discussion Starter #15
So instead of accusing the pump of being a flawed design, which it's not, look at the real problem, North American apathy.
The pump is a flawed design. No need to accuse anything.

If the pump can't be designed to take anything less than ideal conditions...that's a fail to me.

If our fuel is such poor quality...why don't we see frequent failures of ag/construction/off-highway fuel pumps? You don't. It all runs fine on ULSD.

The real problem here is the manufacturers almost intending to have a pump like the CP4. Defined lifespan. More control over you, the consumer, and how long the product they sell you will last.

To GM and Ford...it's metrics. Key deliverables. KPI's.

...it's business.



BUT...it still won't deter me from buying this truck. If I get a whiff of an imminent failure...she's gone down the road.
 

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If I am reading this .gov pdf right, Volkswagen tried to blame the failures of this pump on misfueling. Some of that apparently is correct, with misfueling, there is a 64% more likelihood of the pump failing. However, if you read all the way through this governmental study report (which spans 4 years), this pump failure due to drivetrain failure from metal flaking with no indication of misfueling to be at 88.5% of the reported failures in this study that is separate from Volkswagen's study. Therefore, it is correct that this is a lousy fuel pump. Average cost of repair in this report is $10,000.00. If Nissan is putting out such a wonderful truck, why in the world are they using this crappy fuel pump? I'm attaching the report. I attempted to attach the report but the file was too large. You can see the report for yourself if you google odi.nhtsa.dot.gov hpfp failure. It should be the first site listed.
This is giving me some pause for sure.
 

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Discussion Starter #17
Cruz - nice research! Job well done.

I feel bad for bringing this topic up because it puts some doubt in people. Nonetheless it is a valid topic and concern, especially for those who plan to hold onto their trucks and get the miles out of them.
 

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Where did it say that Cummins used this specific pump model for this particular engine for Nissan?
Since the report was release, did Bosch take action and fix whatever is wrong with the pump design?
Is the pump fabricated at various plants?

I'm perplexed at the idea of a company (other than VW) that would willingly put a sub-par parts on such an important common project...
 

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You can check out this link (among others) that tells you about the pump: http://www.dieselarmy.com/features/history/a-look-at-what-the-5-0-liter-cummins-is-made-of/
Apparently they are putting this pump in with a timing chain attached to time the pump with the combustion cycle for reduced noise. I did read an article that claims this pump is actually more advanced (and flows 20% less fuel) than the CP3 which is in the more current Rams and 01-10 Duramax engines. It sounds like the lubrication in the diesel fuel may have something to do with this. Although there are additives for lubrication, I think you have to be careful that you know what you are doing and also be careful not to void the warranty with additives. The number of pump failures that were used in the study was only 1,255 failures out of 241, 279 vehicles sold in just under a one year span. So obviously not all of these pumps fail. That does lead to some speculation as to what the actual cause is. If I'm going to spend the kind of money that I will be shelling out for this truck (if I decide to get it) then I will most likely get an extended warranty. Normally I would pass on that, thinking along the lines of "sucker bet" but I am just being cautious with this being a newly designed truck.
 

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Isn't the CP4.x pump used in all the German (VW, Mercedes, BMW) diesels, in GM's Duramax diesels, in Ford's PowerStroke diesel, and I think in the RAM's Italian EcoDiesel ?? And of course the Cummins 5L V8.

The only diesel that I'm sure does NOT use it is the RAM Cummins I6.
 
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