Common rail fuel system failures

[Audi5000TDI]

Owning a 2012 Passat SE TDI, I've often wondered why it was that they didn't experience HPFP failures, with their Gen 2 common rail motors, compared to 2009-2012 modeled jettas, JSW's, Golfs and 3.0 TDI Touaregs.

Was it the lower pressure of 1800 bars on the pump, versus 2000 on the other models? Nope, could not be, as the Touareg study manual only runs 1600 bar in their V6, and those still fail also... All the models with HPFP failures run Piezo injectors, the Passat runs solenoid injectors.

Which, to me, isolates the problems with the injectors... as the Touareg also runs adblue, and also runs lower fuel pressures at 1600 bar, but it runs the piezo injectors, and it too fails with HPFP's.

Today... after years of asking around... something came out that probably wasn't supposed to come out. Piezo injectors are failing.... and when they fail, the little ceramic discs inside, be it due to water in your fuel... the moisture under pressure by the ceramic disks turns to steam and fragments/cracks, grenades the tiny ceramic discs, as does the pressure and temp in there if there is gasoline in your fuel cause something like the gas fuel and it's low vapor pressure to "flash" again cracking the ceramic wafers in the piezo injectors. What you have now is very fine ceramic grounds going thru your fuel system constantly.... they don't pass through injectors, but they pretty much pass around the recycled fuel path from the return lines of the injectors, back to your fuel pump, where they do their abrasive insiduous damage, tearing apart and grinding up into metal bits, your HPFP.

The solenoid injectors have no such ceramic wafer discs, they don't crack, they don't crumble, they don't put ceramic bits and pieces into a continous loop to grind up and grenade your fuel system.

And that is why VW and Audi, Ford, and GMC, most likely will abandon piezo injector systems in the North American markets... due to our fuel. We still have problems with North American fuel, and I still recommend some sort of biodiesel blend below B5 for lubricity of at or under 300 micron wear scar, as well as running Power Service White Bottle with every tank of fuel to keep your fuel system dry.

According to my source, who shall remain nameless, it's failed ceramic from piezo injectors that is wrecking the whole fuel system. Fuel pressure in the HPFP may or may not be an issue at 1600, 1800 or 2000 bar pressure.


All of the above is just opinion, and may or may not be fact, you be the judge.

Niner would have posted this on TDIclub, if he still could, but there is a ban happy moderator there that is full of

[Cogen Man]

Very interesting thought. Something to really think about. I have the 2011 Golf TDI. I had my fuel filter changed about a month ago. Only had about 10,000 km on it. The dealership didn't want to do it. I said, so you don't want my money. Okay sell me the filter and I'll do it myself. I wanted to have a look inside the filter housing for any metal bits. They decided to take my money. No metal in the housing and the filter looked good. You could have something with the ceramic on the Piezo's failing.

[chittychittybangbang]

IMHO, too many confounding factors. Different revisions of fuel pump, fuel quality variations, etc. Plus, the Passats are all still pretty new. Also, if someone on another board feels strongly about something he's free to post it himself here. I only delete spam/swears/sex/sircular and pointless arguments.

Good suggestion though. What size of filter could catch these? Also, piezo inj are used with a number of gas cars, why don't they have HPFP failures?

[fastson]

Originally Posted by chittychittybangbang

Good suggestion though. What size of filter could catch these? Also, piezo inj are used with a number of gas cars, why don't they have HPFP failures?

I thought a number of BMW models had HPFP problems. No idea what was the cause though.
If you search on Youtube there are heaps of videos of BMWs with failed or failing HPFP.

[Audi5000TDI]

Originally Posted by chittychittybangbang

IMHO, too many confounding factors. Different revisions of fuel pump, fuel quality variations, etc. Plus, the Passats are all still pretty new. Also, if someone on another board feels strongly about something he's free to post it himself here. I only delete spam/swears/sex/sircular and pointless arguments.

Good suggestion though. What size of filter could catch these? Also, piezo inj are used with a number of gas cars, why don't they have HPFP failures?

If it's the pump that is failing on it's own and not some other mitigating circumstances, we should be seeing failures of HPFP's on solenoid injectored 2012 passat TDI's by now. There should have been at least a few by now, with the heat and summer weather. Time will tell, but if it's isolated to diesels with only piezo injectors, as it is currently...

Bosch has blamed water in the fuel, and gas in the fuel, they all have much lower vapor pressure than diesel fuel, and if they are causing injectors to fail, then Bosch has a design problem with fuel available in the USA, in their piezo injectors models.

I would not buy a CR TDI Touareg with what I know today, until VW /Audi begins to use solenoid injectors on that modeled motor. The current piezo injection model only runs 1600 bar pressure. VW is bumping up the horsepower in this motor for 2013, and I wonder when or if they will change to solenoid injectors for the Touareg.

Or I can hope for a 2013 Tiguan 2.0 TDI for 2013.

[MOBI]

I read with interest your comment on Piezo electric injectors. I have seen tips of nozzle bodies on mechanical injectors blown off due to water in fuel, of course the reason being water expands 1700 times its volume as it turns into steam...........the pressure has nowhere to go so off comes the tip of the nozzle...........fotunately it does not occur very often..........therefore ceramics can certainly breakdown under these conditions.
If you are having problems with free water in the fuel, look at your fuel filtration system. You can obtain 2 micron or even 1 micron filters that will remove water from your fuel..........fuel filtration is the most impotant system when dealing diesel engines.

[Audi5000TDI]

Let's go back to Bosch and ceramic tipped glow plugs in the B5 passat of 2004 and 2005... FAIL, and they changed back to steel tipped glow plugs for that model.

I've run ceramic bearings in wheeled hubs and crank bearings on my mountain bike, and guess what... they failed within a season, whereas I get 2 to 3 seasons out of a set of crank bearings out of carbon steel before they get worn out. Ceramic bearings crumble inside the bearing race.

Now Bosch has been running ceramic again, in Common Rail diesel injector bodies. You tell me what water or even a pinch of gasoline with it's flash point much, much lower that diesel fuel is going to do inside that very hot injector body getting all it's heat from the combustion, from the cylinder head, from the heat coming up the injector tip into the rest of the injector body?

When ceramic cracks and fragments, (as it does, ask anyone that's lost a glow plug tip in a B5 Passat TDI) all those bits go back the return fuel line, right back into the filtered fuel side of the fuel filter, to be rerouted straight back to the HPFP, where ceramic, being a lot like glass and sand with silica in it, tears everything else up.

Watch the 2012 NA Passat TDI with solenoid injectors for the next year for HPFP failures... there is a BIG REASON Bosch takes the injectors and the HPFP together when changing out a fuel system for failure.... and remanufactures them.... Is it the ceramic bits in the injectors that are sh*tting the bed and wrecking everything else? I ask, as a question, I don't have the answers, but you can be damn sure Bosch knows the real reasons....

We need folks that can get their hands on old CR tdi injectors and open them up and see the conditions of the goods inside after a HPFP failure.... this would explain why some folks have gotten complete fuel systems changed out, the injectors failed, and the pump looks almost perfectly fine, even Dwiesel noted that in a few pump samples he'd seen.

Is this the smoking gun we've been looking for? Don't rule out failed ceramic piezo injectors as the root cause... and there is no way VW specified that or called that out, that would be Bosch's decision, the ceramic injectors are quite a bit more expensive than the solenoid models. We all know how cheap VW is... and Bosch claiming to make the pump more robust, 3 different times, maybe even a 4th time with them now being made in slovakia... with only minor improvements... Have they done anything to improve the piezo injector bodies with ceramic parts more robust? Or is it all a smoke screen, leading us down the wrong path, barking up the wrong tree? Someone needs to bring this to NHTSA
s attention to investigate PIEZO INJECTORS being a safety hazard, and to do an Engineering analysis of Piezo injectors which require ceramics just to get the tons of very thin stacked together crystal ceramic wafer discs to respond to 80 to 125v input stimulus to cycle the nozzles.

[xeno555]

Originally Posted by Audi5000TDI

...
What you have now is very fine ceramic grounds going thru your fuel system constantly.... they don't pass through injectors, but they pretty much pass around the recycled fuel path from the return lines of the injectors, back to your fuel pump, where they do their abrasive insiduous damage, tearing apart and grinding up into metal bits, your HPFP...

Could you point out to me where the injector "return line back to the pump" is? (I don't think there is a fuel return line from the injectors).

Also if this was happening, as soon as the injector fails, it would throw a CEL or a flashing glow plug light, then failure of the pump shortly after?

Would all the injector fail nearly at same time?

How about the fuel samples sent for analysis (due to misfuel or HPFP failure) would all/some show ceramic FOB?

[potiron]

Thanks for this Audi5000.

This is one of the few theories that actually makes sense. Is it possible for you to get this info. over to the NHTSA folk who are looking at this issue? Maybe it's pointless, but they might give it a test?

I'm a new member with a 2009 Jetta TDI that experienced HPFP failure and the $10K fix (under warranty). Also, in that strange purgatory of wanting to buy a new TDI Sportwagen (2012 or 2013) because the TDI is "my perfect ride" - but I'm fuel pump failure freaked. Oh well. Thanks again for the post. I've never seen anything like it on the TDIclub.

[chudzikb]

Are these particles too small for the fuel filter to remove? I would think it would take some time for the ceramic particles escaping the fuel filter to take out the pump? Would not the destruction of the injectors throw some kind of a code before the pump gets trashed? I know there are many wiser than I that will have the answers to this. Somehow, I don't see VW stepping up to help fix the problem. The problem will recede with the next design, which will speak volumes about what the problem actually is with the system.