AXD PD Seal Kit / Cold Engine Speed

Hello,

I bought a T5, and after some time, the engine doesn't start immediately.

Now I want to re-seal the PD elements, but I'm not 100% sure if this is the correct sealant.

Motor AXD, 96kW, manufactured in 2004

Kit: Repair Kit, Pump-Nozzle Unit BOSCH 1 417 010 997

Can you please confirm if it is correct; I am not entirely sure after some searching.


Thank you!

So, I would first conduct a thorough investigation, rather than simply removing the PDEs. I wouldn't even start with that, because of the risk of thread damage.

How long has the engine/bus been standing?

Thank you for the response.

The bus has been out of service since Saturday, so for 4 days, and it needed approximately 30 seconds of cranking to start after it had been refueled.

With 250,000 km, I don't think it's too early to replace the seals, even though it hasn't shown any signs of rough running yet and the oil is still good.
It's better to switch too early than to allow the PDEs to become established.

The Bosch part number matches this PDE type. However, a better option would be the Elring part number 900.650. There, you'll find the ball bearing, so you don't have to buy it separately from VW.
Nevertheless, it is true that I would only perform the PDE if I am certain that it is necessary. The keyword is "fuel pressure in the intake". (Use the search function)
In case you do, pay attention to the engine's initial adjustments in the injector bore area, specifically around the zero rings.

The Bosch part number matches this PDE type. However, a better option would be the Elring part number 900.650. There, you'll find the ball bearing, so you don't have to buy it separately from VW.
Nevertheless, it is true that I would only perform the PDE if I am certain that it is necessary. The keyword is 'fuel pressure in the intake'. (Use the search function)
In case you do, pay attention to the engine's adjustments in the injector bore area around the zero rings.

Thank you!

Yesterday, I did a few things that, in my opinion, need to be done when you get an AXD: Replace the right drive shaft and install part number 50601 with oil.

I believe that it is now running more smoothly, and the starting problem no longer exists. However, he also didn't stay for several days.

Ist der Dichtring von Elring mit der Nr. 900.650 hinsichtlich der Qualität dem von Bosch gleichwertig? I had seen him before, but that's why I had concerns!

Under 'fuel pressure in the feed', I couldn't find anything; however, I can already imagine what you mean.

If the fuel pressure values in the cylinder head are within the specified range, it would be pointless to remove the injectors. In this case, a thorough investigation is necessary to identify the cause of the problem. You should do this first, rather than simply assuming that the rings are the problem based on suspicion.
The thread on the clamping block in the head doesn't allow for unlimited actions like that.
That's what the previous speaker meant.
The tool for measuring is called VAS 5187. This has already been discussed in the forum.
Regarding products from the Elring brand, I personally have nothing to complain about. Why would I? It's a well-known and reputable company. The gasket set is also available from Reinz. And without the ball screw. I also find that perfectly fine. Depending on what your supplier offers and where you can easily get it, in the event that the repair is carried out, you will have to go to VW and buy the screws.

Thank you for the assessment(s).

Now, let's just drive and check the described items one by one. Thank you also for the part numbers for the gasket set and the VAS 5187 tool. I will talk to my VW mechanic about this.

Now that the car is reliably starting up after about 1 day of being parked, my initial panic has subsided.




Regarding the general issue of the sealing rings in the cylinder head of PDEs sinking, wouldn't it be possible to simply mill away the lower seat (essentially the stop) by 1 mm, so that the PDE sealing rings sit 1 mm lower and thus get undamaged ZK material as a counterweight?

Hello,

I received the accumulated invoices from the previous owner today.

This indicates that the PSEs were sealed approximately 20,000 km ago, and that the rings in the ZK (presumably a component) also showed clear wear marks.

At the VW workshop, the mechanic said that the only thing that could be causing the symptom (no fuel in the intake) is the seals. However, since these were replaced, I must continue to look for the problem. (Since the symptoms were the same before and after the change, I suspect that this is not the cause.) New rings should, despite the inlet marks, bring an improvement.

Fuel pressure is correct in the ZK.



Can the fuel system be pressurized to identify the leak?

Without creating a new topic, I would still be interested in your opinion on my idea:

The PDE rings are inserted into the borehole wall. This increases the play between the sealing rings, and they can no longer seal properly.

If I now shift the PDE down by 1.5mm (ring width), the sealing rings will again have straight walls and can seal properly.

Questions that occupy my mind:

- I have reduced the 2 mm at the bottom of the shafts; that is, the respective diameters are at least 2 mm below the respective sealing rings.

-arise thermal issues towards the combustion chamber if the nozzles are 1.5 mm further into the combustion chamber?

-Does the nozzle possibly engage with the piston?

-Are there any thermal issues at the lower surface of the PDE if the density discs are made 1.5 mm thinner?

or would it be possible to shift the PDE slightly further up?

Does the end still have enough access to the combustion chamber?


I would like to hear your opinions! Thank you.

Quote:

The PDE rings are inserted into the borehole wall.

Let's say this: The PD (presumably referring to a specific component or system) is essentially figuring things out on its own, and as a result, the seals wear out until they eventually stop working properly - then things get complicated.

engl wrote:

Fuel pressure is correct in the ZK.

Then it's fine. Then you can leave the rings alone if it suits you.

Looks like there's not much room for new grooves. Furthermore, the fact that there are 2 fuel rails running lengthwise through the head makes it more difficult. The injector needs to be at the correct height, otherwise it will wear prematurely. If this happens, then the only solution is to replace the head.

Also, I had the same problem, and the only solution is a new ZK.
Unfortunately, it {OCCURS} quite {FREQUENTLY}.
Also, make sure to also replace the water pump as soon as the head is removed.

Here you can see another used injector of this type. The typical wear marks in the upper ring area are clearly visible. Now you also know how much you would need to move it to get out of the faulty area. I don't think this design is suitable.
The engine, from which the PDE came, is still running today. With the same head. I had torn small pieces from a cleaning cloth and used them to close the injector bore towards the combustion chamber and to smooth the edge. Then I removed the cloth and installed the injector again. The area where the zero ring sits was fine. However, it was necessary to ensure that the new zero rings did not damage the injector during installation. In effect, when they are pushed into their mounting position through the scratched areas.
Maybe they didn't do that for you. However, the fact that your pre-compression is correct, as you say, speaks against that. So, a motor that stutters usually has a problem with the middle ring. If the upper seal is leaking, there would be leakage between the oil and coolant circuits.

I understand everything now, yes. Thank you!

I know how the shaking feels when the rings are leaking, I've experienced it firsthand. It's like new again thanks to the new rings (see other thread)

He absolutely doesn't stutter.

When, after the vehicle has been stationary, the ignition is switched on (obviously, ignition for diesel... -> just turn the key), the pump in the tank will initially run, and you will be able to hear it gurgling loudly until the line is full. But that doesn't necessarily mean anything, does it?




I will now continue to monitor the oil level.

engl wrote:

When, after the standstill, the ignition is switched on (obviously, ignition in a diesel engine... -> just turn the key), the pump initially runs in the tank, and you can hear it gurgling loudly until the line is full. But this doesn't necessarily mean anything, does it?

No, it doesn't. Presumably, you won't hear the gurgling at all when the tank is full, because it actually comes from there, as long as air is being purged from the last section of the return line. And this doesn't happen if the fill height is above the return opening.
The pump runtime is rigidly programmed and independent of the filling of any pipes.

BTW, I don't consider achieving the target advance pressure to be a completely reliable indicator that the PDE seals are completely leak-proof. Because with small leaks, the pressure will not necessarily drop to the specified range.

One could follow this and, for safety, also check the GDP. If there is air in the injector, the needle will close faster due to the lower resistance. This results in the GDP showing more or less strikingly high negative values.
One might even be able to recognize the cylinder that is out of sync, or even if all 5 are running too fast, there could be other problems with the fuel supply to the head. Possible causes could be: Diff, Tandem pump, or pre-feed pump.