After my wife's hpfp failure back in Sept of 2009 I started to try and determine why her hpfp failed. Since then other hpfps have failed across the country. The main reason at this time seems to be low or lack of lubricity in some fuels. So,some fuels make some hpfps fail.Through hours and hours of online forum discussions,emails,phone calls and picking anyone's brain that even knew one thing about diesel engines I and others came up with the conclusion that the roller/cam was failing. Any of the failed pumps that anyone took apart showed a failure in the roller/cam. I myself had disassembled a couple of failed hpfps. The cam/roller seemed to be the culprit in the failures. Lack of lubrication at the cam/roller was causing the pumps to fail sending metal particles throughout the entire fuel system. I thought we had it after tons and tons of discussions. There was one nagging thing that always bothered me. Some people had a few metal particles on their fuel filters when they did a fuel filter change,but seemed to suffer no ill effects. Their hpfp's were fine. Still running as good as ever. So where were these fine metal particles coming from? Finally in November of 2010 while driving to a local coffee shop it hit me. Its the aluminum bore! The cam/roller failure as previously thought to be the main component failing was the result of and not the cause of the pump failing. These first tiny particles are made in the aluminum bore of the hpfp. In this aluminum bore there is a steel piston cup that holds the roller. Without sufficient lubrication this steel piston cup wears the aluminum bore at an extremely accelerated rate. Once this piston cup starts to make aluminum particles these particles can become trapped between the roller and roller holder. The particles then start to scar the roller and roller holder,making even more metal particles. If enough particles become trapped between the roller and holder the roller can seize up. At that point the seized roller will start to damage the cam. Cam and roller now make more metal particles at a very rapid rate. Even though the cam and roller are failing or failed the hpfp can still make adequate fuel pressure. The stroke of the high pressure part of the pump is unchanged until the cam and roller catasprophically fail. This is when the engine will go into limp mode or quit entirely.
So, in summation its not the roller/cam that are the precipitators of the hpfp failing. It is the steel piston cup accelerated wear on the aluminum bore because of lack of lubrication.
I would stongly advise all CR tdi owners to take steps to insure the fuel they use has sufficient lubricity. Since there are no practical ways to test each fuel up for the fuels lubricity specs, I would suggest that B2 to B5 biodiesel be used along with a lubricity additive. Do whatever you feel comfortable with. I myself add 1 quart of B100,plus Stanadyne Lubricity Forumula to each fuel up on both our 09 tdi's. Lubricity is critical in the new CR hpfp.
I'll up date this thread with pictures or info others may suggest.
dweisel
LUBRICITY,LUBRICITY,LUBRICITY!
Below pics:
Steel piston cup with roller. Note severe wear to piston cup and roller on the right.
hpfp cam. Note severe wear on the uppered pictured cam.
So, in summation its not the roller/cam that are the precipitators of the hpfp failing. It is the steel piston cup accelerated wear on the aluminum bore because of lack of lubrication.
I would stongly advise all CR tdi owners to take steps to insure the fuel they use has sufficient lubricity. Since there are no practical ways to test each fuel up for the fuels lubricity specs, I would suggest that B2 to B5 biodiesel be used along with a lubricity additive. Do whatever you feel comfortable with. I myself add 1 quart of B100,plus Stanadyne Lubricity Forumula to each fuel up on both our 09 tdi's. Lubricity is critical in the new CR hpfp.
I'll up date this thread with pictures or info others may suggest.
dweisel
LUBRICITY,LUBRICITY,LUBRICITY!
Below pics:
Steel piston cup with roller. Note severe wear to piston cup and roller on the right.

hpfp cam. Note severe wear on the uppered pictured cam.
