CR engine HPFP analysis

[oilhammer]

This is the sharing of info thread, to post pics and possible causes.

These are from a 2009 car, not my pics and if the sender wants to be identified it is up to him.

Here is the pump taken apart. Note the left end of the part labeled 'piston' is where the little tiny roller is located.



Closeup shot of that piston's roller:



Close up shot of the shaft cam that roller rides on:



I have another one here, looks pretty much the same EXCEPT it has no signs of the rusty residue on it. In fact, it is squeaky clean inside.

This is the shaft, you can clearly see how much is worn away at the apex of the cam lobes:



And here is the little roller piston:



Sorry for the crappy focus, my camera is old and my skills are even older. But the wear marks on the roller could very well have been caused by the little roller getting turned off-square from the shaft's cam lobes.

[Luv My 02 TDI]

Any doubt that the rust on the camshaft is rust? Could it be varnish or a protective coating from when it was made? It looks like that edge is beveled.

[dieseldorf]

Brian, is that rust or overheated (coked) fuel?

The cam surface looks rough... clearly lost the ground surface and was wearing out, which is a source of heating

Are you going to be able to pull that roller out of the piston and get more pics?

[ruking]

So to me it begs the question would a "lubricity agent" such as Power Service, etc have prevented the camshaft and roller it sits in from scoring?.

Keep in mind VW does NOT recommend lubricity agents such as Power Service, etc.

[DoctorDawg]

Houston, we have data! Thank you, oilhammer and mystery donor! Keep it coming.

Can you share any metadata...how many miles on engine at failure, did the owner use an additive, failure mode, etc.?

[oilhammer]

Just to clarify, the above pics were sent to me, they are not mine, this car is not in my shop, nor are any of those parts.

I do have another pump here, from another shop that was sent to me, that is apart and other than the rusty stuff, the wear looks pretty much exactly the same. The pump I have was off of a 31k mile 2009 car.

[dieseldorf]

Did the car just die on the side of the road or was it a driveability issue?

[El Dobro]

What keeps the piston from turning in the bore? Is there a flat?

[Jim'stdi]

Where do the AA batteries go???

[Rauss]

That's pretty scary... time bomb!

[740GLE]

I'd agree that the rust doesn't look like rust, but I imagine oil hammer would know rust when he sees it. Very interesting.

Also was this pump pulled from a wrecked car or was there a failure in the fuel system?

[oilhammer]

The above pics came from a 2009 car, it died shortly after refueling. Dealer found cloudy fuel in the car, and a low pressure DTC. They replaced the fuel and filter, sent it on its way, but warned the customer there may be a problem, even though the car at that point was running fine.

It came in the next day on a hook, with the fuel system full of metal. Again, the above pics are NOT mine.

[Pelican18TQA4]

Subscribed!

[birkie]

Fascinating.

As I understand, the pump is supposed to have a Diamond-like carbon coating (DLC) somewhere on the piston as additional protection against our fuel here. I'm not sure if it is possible to tell with visual inspection - but do the sides of the piston look any different from the cam or roller as far as possible coatings/treatments? Is it possible that the cam and roller are not coated in this design? I'm no material scientist, so I don't know if that would even make sense.

[oilhammer]

The piston itself looks to have a gray finish, yes. And the one I have here has that finished galded completely off both ends of the piston.

But it is the piston's little roller that looks like it went from a roller bearing to a friction bearing....