Correlation does not Prove Causation
Interesting to note: 2 pump failures shortly after installation of the 2Micron filtration system. If this system came from VW, all the posters would be blaming the dealers and VW.
Well, I may be new to this forum, but I've looked over this issue extensively after finding metal particles in my filter at last change.. which is NOT normal (I have a Diesel truck with more miles on the filter, more fuel passed through it, same fueling stations.. NO METAL).
I'm also a Mechanical Engineer, and looked at the various pictures showing failures, as well as the internals of the pump's design.
I'm convinced by the evidence, that this pump is poorly designed, and was used because of how much easier, and cheaper, it is to manufacture than the CP3 version (which has no cam/roller within it). The cam roller is not a good design, it is subject to wear, perhaps poor fuel makes this much worse, but I'd say in the best cases of fuel, it remains a poor design. There is nothing but spring pressure, and the rising/falling profile of the cam/roller that prevents rotation of the roller (which means it can begin to rotate at top or bottom of pump cycle, at 4 times per revolution! What happens when you stop the engine and some residual torsion in the coil spring is acting to rotate the roller (top or bottom of cam)? It may rotate, then next engine start disaster!), in several documented failures, as in this one, the roller has rotated and caused massive metal contamination and failure.
There is nothing to the 2microntech kits that can contribute to failure of this poor design, but quite a bit that does in fact greatly reduce the massive system contamination and costly damage. Frankly, VW should not use such a sensitive pump, but clearly feels MOST of the time they will last for at least 120K/10 year (hence the warranty extension). They extended the warranty, because the MANY complaints of this pump failing, and I can be sure the vast majority of those failures do not have the 2Microntech kit, and also do not post on this forum, or even do more than drive and fuel their vehicles.
One thing to note, over at the massive list of complaints on the NHTSA site, about 180+ and counting, the common theme is failure happens suddenly, with no warning, often in traffic, and the engine dies, and won't restart. In the case for the failure that is subject of this thread, the failure was much more gradual, showing that controlling the metal contamination by the 2Microntech kit provided at least some warning, and some ability to not be stranded..
In my case, showing the metal to my VW dealer, and discussion with VW customer care over the issue, it becomes crystal clear to me that VW policy is to gamble that most pumps last to or beyond the extended warranty, and in my case they do nothing until if fails catastrophically, they are OK with the metal particles in my filter (clearly telling me wear is occurring and I might not get to the 120k/10yr, but warranty or not, I do NOT like having a car I can't trust, knowing it can fail at any time without much or any warning..
To be fair, VW is not better or worse in this regard over other vehicle OEMs, I've had issues with GM, and Chrysler with other vehicles, similar attitudes in those cases as well, the difference in this one is the long list of failures, the appearance of what to me, from an engineering POV, appears to be a poor design and the reluctance to do a preventative and permanent fix, this tells me VW has calculated the cost to "fix" it as being more than dealing with the occasional failures, and the consequences resulting from such.. clearly some are getting lucky and going well past 120K without issue.. but who knows when that ends, the pump will fail eventually, and when it does, it will be very EXPENSIVE, likely total a car if it has many miles and years on it at that time.
One other thing I looked into was HPFP failures from other CR diesel vehicles, seems the newer GM and Ford are having issues with the Bosch CP4.2 (a 2 piston version of the VW TDI pump, CP4.1), but the Cummins (Dodge) does not have these issues (uses CP3), nor the older CP3 HPFP GM vehicles, so it seems clear to me this design is at best overly sensitive to fuel quality, or just a poor design period, a ticking time bomb for a catastrophic failure, sure some get lucky, but I'm not usually in that camp!
