Bosch VP44 Injection Pump Failures Explained (from Blue Chip Diesel Performance)

[Archive]

Did I mis-read this?

The way I read this article is that the "additional pump in the Injection Pump" quits delivering fuel when you decelerate... not the lift pump!



Maybe I mis-read it... I will go back again.



Steve... thanks for taking the time to post this for all of us. I am glad to see you helping to dispell some of the rumors going around, even from some highly respected mechanics!



And a thank you to Blue Chip. Research like this helps us!



After almost two years, I still love my Blue Box!

 

[TowPro]

2 bits of information here from the VW Diesel guys.



Do not use auto trans fluid in your diesel. It actually has an ingredient that causes pump wear! They used to run this in the older rabbits when US changed to "lower" sulfur fuel, only to find over time they actually did more damage to there injector pumps.



Over the last 2 years or so I have been hearing reports of guys running 2-stroke oil in their VW Diesels. I have heard no reports of failures of any kind. Every person who has tried it says there fuel mileage went up around 10%. If they run a tank without it, there mileage goes back down. Some of the guys on the list are Engineers, and want to know "why does the mileage go up?” They have tried to talk to chemist and oil manufactures but no body can explain this. I personally was talking to the ELF rep one day explaining our findings; he said, "I will look into it" but never heard back anything from him.



Keep in mind these guys are running both the older VW diesels, as well as the new TDI which uses a Bosch pump just like our Cummins (only 2 less cylinders). I have not heard any reports of Cummins guys running 2 stroke oil, anybody want to try it and tell us how much there mileage changes?

 

[TXRam]

First off, I am glad someone, Chip, is working on figuring out the problems. Thanks for posting this Steve.



TopFuel, I still believe that injectors are less "straining" on the injector pump. Maybe not a problem. But if you have one of the inadequately de-burred pumps, bigger injectors should not have the effect that a box does. That being said, I run boxes on my truck, so obviously I don't think it causes too much strain.



Rob, both of the pumps in the VP are positive displacement, the 1st pump is a vane pump and the 2nd is a rotary piston pump - 2 pistons on either end of a "chamber" the assembly rotates inside a "cammed" housing which causes the two pistons to move toward each other, thus pressurizing and pumping the fuel). This info is all from the Bosch CD that I received a few months back - it has some good info, but not as much as I would have liked.