Bosch High Pressure Common Rail System??

[HBarlow]

Can someone clarify this for me?



I have seen a German name, "Bosch" I think, used in literature describing the Gen III HPCR fuel injection system. I have also seen similar language used to describe the fuel injection components of the Duramax diesel engine used in Chevrolet/GMC light trucks. The name is also used in connection with the Gen II 24 valve Cummins injection pumps and injectors and, I think, the earlier 12 valve Cummins engines as well as all Mercedes-Benz and other German and European diesel engines.



I've heard and read many times of replacing all eight injectors on Duramax engines at surprisingly frequent intervals. I have talked to a couple of honest transport drivers who own Chevy/GMC trucks who have admitted replacing their injectors. One driver recently told me he had replaced the injectors on his 2004 or 2005 GMC dually at around 30k, 70k, and at just over 100k miles. He frankly stated that he figured the injectors are only good for about 30k miles. He said that each replacement was covered under warranty by GM but the last time, only because he had bought the truck from a dealership owned by his son-in-law. He said the bill for replacing all eight injectors was around $3200.



I've heard of a few isolated incidents of Gen III Dodge-Cummins trucks with one or two bad injectors but I don't think I've heard or read of anyone replacing a complete set of six. I certainly have not heard of routine replacement of sets of six injectors on Cummins HPCR engines. I've talked with many RV transport drivers with as many as 250k or more miles on Gen III HPCR Cummins Rams who have not admitted replacing injectors.



My question concerns the name Bosch used when referring to the Cummins HPCR engine vs. the Duramax diesel made by Isuzu. Does the name Bosch used when referring to HPCR injection systems mean that both Cummins and Isuzu use a Bosch design and the engine companies pay royalties to Bosch because Bosch holds a patent? Do Cummins and other diesel engine manufacturers such as Isuzu manufacture their injectors and injection pumps using a Bosch patented design? Or does Bosch manufacture and sell the HP injection pumps and injectors to both Cummins and Isuzu to meet the needs of the engine manufacturer's engine design? Are the injection pumps and injectors used by Cummins and Isuzu identical or similar? I'm almost certain they are not interchangeable. And if the latter is correct, why do I hear of routine injector failures and replacement of sets of all eight injectors on Isuzu diesel engines but only isolated reports of occasional bad injectors on Cummins HPCR engines?



Can anyone explain this to me?



Harvey

 

[Idaho CTD]

Bosch does all of the above motor configurations you mentioned. They manufacture all of the components to meet the needs of each individual manufacturer. The Dmax uses essentially the same CP3 injection pump as the HPCR Cummins. The case is just slightly different for mounting to the motor. The injectors basically function the same but are quite different in appearance so they are in no way interchangable. I would say the design of the Cummins injectors are better and therefore fail less often but that is just an opinion.

 

[Devan Manis]

I think that you will find that Bosch does ALOT of parts for ALOT of diesels. I think all the injection pumps and injectors for all years of the CTD put into pickups are made by bosch also.

 

[Bugracing]

As Devan says, Bosch is a supplier to many OEM's (original Equipment Manufacturers). They supply the majority of European makes and many US makes.

A manufacturer will provide its parts/component supplier with specifications for the part, which the supplier makes. If there is an issue with the part, and you enjoy pointing fingers, start by pointing it at the manufacturer of the vehicle you purchased. Also keep in mind that EVERY manufacturer tries to build each car/truck as cheaply as possible to maximize the profit per unit.

The DMax's injector failure HBarlow is noting could be the result of many factors: poor quality part, poor quality fuel, and fuel filter issue. The fact that the last injector change was "covered" under warranty is questionable - the dealership will most likely get charged back as this repair is well outside of the limited factory warranty or powertrain warranty. This instant may even result in a warranty audit of the dealership's service department as possible warranty fraud. This may come as a surprise to many of you, but keep one major item in mind – that driver’s GM product is being used as a commercial vehicle and most manufacturers’ limited factory warranty excludes commercial use from warranty inclusion.

 

[Devan Manis]

Im not sure if that one driver that you talked to is aware that gm extened the warranty on the injectors to 200,000 miles so that was probably what he got.

 

[rbattelle]

Im not sure if that one driver that you talked to is aware that gm extened the warranty on the injectors to 200,000 miles so that was probably what he got.

I also heard that DMAX injectors had greatly extended warranties due to high failure rates. If it's true (and I think it is), it might be the only redeeming quality of GM. (okay, that was a bit harsh).



I have often wondered why DMax injector replacement rates seem to be so much higher than HPCR Cummins. One theory (of mine) is that the early DMax injectors were 1st-generation (2000-2002), and by the time Cummins started using them they had been redesigned (as a second-generation, of sorts).



Another theory (of mine) is the presence of a small steel mesh filter in the injector line on the Cummins trucks that is perhaps missing on the GM trucks. I have no idea whether the GM trucks have it or not, but if they don't it might contribute to a higher failure rate.



I'm not sure just how much say any customer has when it comes to the design of a component manufactured by Bosch. If Cummins has exceptional influence over what Bosch does to the injectors bound for Cummins engines, then I'm inclined to believe that Cummins did better research than Isuzu.



I attempted on several occassions in 2003 to contact Bosch to ask them specifically about the design of the Cummins injectors, but they never responded.



-Ryan

 

[Wayne M.]

I thought I read somewhere that the Duramax fuel system components were supplied by Delphi.

I'm not disagreeing with anything previously said here, but maybe Delphi is making parts under license from Bosch? In this case, I definetly would believe a higher failure rate. Maybe GM has so much support because they have a direct stake here?