Ford's answers to the NHTSA 6.7 Investigation

NewsW wrote:

BenK wrote:

Alu HPFP body !?!...what is the alloy and temper?

What drives the pump shaft...cog belt, chain, gears?

Each of these drive mechanisms have a different issue --- generating its own unique patterns of frequencies.

Remember the patent to raise the pump off the engine? Isolate thermal? Vibration? Both?

RE-BUILT

amazing that they would and then ask what do they do with the bore and piston...heavens...hope they don't keep them, or is the DLC so good that there is no wear...rhetorical, as the failures tells me it should be re-bored/coated


What I have seen of "rebuilt" operations is they simply test the remans for volume, etc. and will replace things like a coil in the injector (for the coil activated) or the piezo electric element, but they don't touch the coated stuff. It either re certifies or it doesn't.

Bosch reman will have to speak to this issue.

Alu cylinder and what is the piston material?

Would assume that the materials are different, so they are playing with thermal expansion coefficient deltas to expand the outer a bit, let the clearance open up with temperature, and with it, cooling from leakage.

Downside of that is that if any particle is trapped on stopping, it is jammed in there tight and will probably score the cylinder bore / piston before it is ejected on the next cold start to warm cycle.

Then does the piston have a ring or whatever to seal?

That then begges to ask what is the thermal co-efficient of expansion of those two?

Need to see pics, but I don't think it is ringed.

DLC's co-efficient of expansion?

The layer will peel, but I don't know the characteristics off hand --- have to know the coating on it first.


A new one based on NewsW and Niner's comments. On the pump shaft
and the bearing seal...now wonder what they did to keep the shaft
from moving axially from the piston, which begets questions on the
PSI, stroke, etc. If the bearing is it, then more questions on
that bearing and seal for BOTH ends of the shaft...equal and opposite force...
Oh never mind...90* to the axis of the shaft... :)



Looking at the various diesel chem mixtures is interesting and that
there are failures all over the place. Interesting to read that they
have ID'd it to regions along with seasonal failures...telling that
H2O and some chemical reaction along/with/by/etc telling.

Since a world wide pump, the lowest the dictating metric(s). Is that
North American?

North American Diesel is far from "worse", worse case in most parts of the world is far worse.

See a link I am PMing to you about what needs to be done with African diesel to make it useable.


Seasonal and heat is a big clue that it is chemical.

There have been quite a few occurrences that I've read about on TDI club from folks that had the car running fine, 1/2 tank of fuel left, from a long drive, shut down, ( hot, cold cycle) start up the next morning, make it a half a mile down the suburban 25 mph street, and boom, the motor goes dead as a door nail, never to start again.

There have been many cases where VW's went in for 20,000 mile services which include changing out the fuel filter for the fist time, and within a tank of fuel, the HPFP has failed... the procedure for bleeding all the air out of the new fuel filter requires VCDS software to cycle the fuel via soft ware 3 x for 2 minute intervals to saturate the fuel filter and get all the air out of it. Coincidence that the HPFP fails so soon after a technician changes out a fuel filter? I think not.... there is also no water trap release on the bottom of teh fuel filter cannister on a TDI, you have to go in from the top with a syringe /turker baster, and suck the water off the bottom, out of the cannister with 10" of aquarium hose through a vent at the top to get the water which is heavier, out of the fuel filter cannister.