Rawze Bomb Squad

[JimT]

(02-04-2021 )Rawze Wrote:  I don't even think that cummins designed that system... I think it was Bosch, as I have seen related info in the past on this... but not sure about it.

I used to work with industrial systems that had 30,000+psi pressures in the past. It usually takes several dozens of pump stages where each stage only has to deal with a much smaller differential pressure, stringing them in series. I would imagine that this is impractical on an engine where space is severely limited.

Personally, I don't know why they did not design a staged pump into the cylinder head on its right hand side so that no one stage had to deal with such extremes. There is plenty of room for a second cam that could have been used for just this purpose... just my opinion any ways.

I did little digging some time back. Yes, these pumps are made by Bosch and yes they have the same issues on other trucks/engines (Big class action with GM related to Duramax fuel pumps failing). Try a google search for "bosch fuel pump failure". Reading about those other pumps lead to my speculation in other threads on here about poor lubrication being the underlying cause. Possibly due to differences in diesel fuel lubricity or, as noted in the class action, air pockets in the fuel (or even the oil) that inhibit lubrication. Given the pressures and stresses involved with these pump designs along with the tight tolerances of the parts it wouldn't take much to cause excessive and repeated wear, then eventual failure.