Set up tax times & PD elements Pump nozzle motor (Fachartikel)

The camshaft of the 1.9l/2.0l 8V TDI PD engine not only operates the intake and exhaust valves, but also the PD elements (PDE) via rocker arms. In the 2.0l 16V PD TDI, the exhaust camshaft operates the PD elements.

To check the camshaft timing, a diagnostic system such as VCDS is necessary.

Injection is only possible as long as the injection cam transmits force to the PDE via its rising edge.

The shape of the rising edge determines the timing curve during injection.

Any adjustment of the camshaft therefore not only shifts the gas exchange, but also the possible timing window for injection and the timing curve relative to the camshaft position.
[b]
Similar to a distributor pump that is set too late, a PD-NW that is set too late at the beginning of the target injection (within the Pmax range) can delay the actual injection start.

However, in this case, the injection at the PD engine will end at the normal time, and therefore the injection volume will be reduced compared to the target value, while the VP 37 will still inject the target volume - but only too late.
[b]
Practical experience on an ASZ engine revealed that adjusting the factory camshaft timing by approximately 3°KW towards earlier timing (as described below, the KW position on the camshaft according to the marking on the gearbox flange is in the OT position) allows the engine to run smoothly during full throttle acceleration in the upper RPM range, while it becomes sluggish above approximately 3500 rpm with the factory setting.

The effects of adjusting the camshaft should be similar for all PD engines.
Therefore, if a PD TDI, for example, loses bite noticeably during full throttle acceleration in 3rd gear somewhere between 3.000 and 4.000 rpm, one should also consider the possibility of an "incorrect" engine control setting, in addition to the usual suspects like LMM and boost problems.

The camshaft timing can also be used to specifically influence the engine's power characteristics (within certain limits).
A slight power increase in the upper RPM range also seems possible with a more "early" setting, see:
/viewtopic.php?t=6847

The position of the camshaft relative to the crankshaft can be displayed via OBD (e.g., with VCDS), the corresponding measurement is called "Synchronization Angle". You can find it in the measurement block 4 of the engine control unit.

More about the Synchronization Angle:
/viewtopic.php?t=14944

The "setting according to the manual" with a marking tool on the ZR wheel of the camshaft (instead of according to the OT marking on the gearbox flange) may be intended for environmental reasons, but it is possible.
If this is the case (unfortunately, no secured information is available), changing the camshaft timing to improve engine responsiveness may lead to exceeding emission limits and thus, legally, to the revocation of the vehicle's approval!

The adjustment and possible correction is possible for the DIY enthusiast without exotic special tools, if you improvise.
Adjusting the PDE is also relatively simple - the biggest individual task is removing and re-fitting the valve cover.
With these two tasks, you have essentially the complete mechanical engine adjustment under control for the 1.9 and 2.0 PD engines.

As a minimum, you only need the following tools for both tasks:
-> A measuring tool of at least 7 cm length and 6 mm diameter, smaller diameter tools are helpful. The measuring tools should be designed so that they cannot fall into the lower ZR channel at the "touching end".
-> A torque wrench and ratchet with 10, 13 mm and 18 mm nuts, alternatively open-end wrenches, a marking pin and a ruler
-> 6 mm Allen key
-> Tools for removing the upper ZR cover and, if necessary, for removing interfering air intake pipes. The openings should then be closed with verschandeln cloths.
-> A flat surface that allows you to push the car forward and backward over at least 1 meter.

To avoid having to rotate the crankshaft by pushing the car, it is recommended to use a suitable key to rotate the crankshaft. If access to the crankshaft wheel is difficult, the pushing method with two helpers is recommended.

For the
[b]NW Setting[/b]
First, remove the upper ZR protection on the 1.9/2.0l 8V TDIs and expose the OT (timing) opening at the motor-gearbox flange.

Then, look for a marking "3Z" or "4Z" on the part of the upper ZR protection on the engine block → Image 1, here the relief writing is highlighted for clarity.
Instead of the 4Z marking, a 3Z marking may be present in the area of the tensioner/crankcase flange.

In the engine's test position, the OT (timing) of cylinder 1 has the notched window in the tooth part of the NW (crankcase) wheel approximately at the 11 o'clock position (Image 2), and one of the Hall sensor markings (two small metal tabs on the engine side of the NW wheel) on the Z marking. The tip of the Z marking points towards the center between the metal tabs (Appendix 2, Image 1).

A difference between the factory/workshop setting and this instruction can result in the fact that the KW (crankshaft) is not exactly in the OT (timing) position according to the crankshaft marking when "crankshaft stop" is used, but slightly after OT, approximately the mentioned 3° KW.

This difference between the setting position with the crankshaft stop and the OT marking during the engine control (NW tooth wheel) setting is the reason for the differences in the engine's power characteristics.

To set the crankshaft stop, the belt wheel/damper must be removed from the crankshaft and the lower ZR cover must be removed.

To check the NW (crankcase) setting, the engine
[b]from a forward turn[/b]
Place the guide in the OT of the 1st cylinder. The guide should then be in the specified position, and ideally, the 6mm marking tool can be fully inserted (6 cm). (Appendix 2, Image 2)

If not, try using thinner marking tools to see if the guide at least stands near the marking position.

Note: Behind the clearly visible marking long hole on the outer part of the NW wheel is the actual 6mm marking round hole on the inner part of the NW wheel.

Only if this hole exactly aligns with the marking hole in the cylinder head, can the marking tool be fully inserted, otherwise it will hit the side of the cylinder head!
[b]Attention:[/b]
If the NW has been adjusted by reversing the rotation, the normal forward side of the ZR is no longer properly tensioned, and the KW (even with the NW properly adjusted!) is more or less facing the OT, which effectively looks like an "early" adjustment of the NW.

If the 6mm adjustment tool for the NW cannot be easily inserted into the KW-OT (or when the KW has been adjusted), then the adjustment is incorrect - to correct this, the toothed part and inner part of the NW wheel must be rotated against each other.

To do this, the 3 clamping screws must be loosened by approximately ½ turn.
[i]Important:
When tightening the 3 clamping screws later after adjustment, the torque of 25 Nm (for a cold engine (2.0l 16V TDI: 30Nm)) must be strictly adhered to.
If you don't have a torque wrench, then...
Before loosening the screws, mark their positions.
, for example, by drawing a line across the screw head with a ruler, pointing directly to the center of the central screw. When tightening completely, you then turn the clamping screws until the lines point back to the center of the central screw.
Okay, I understand. Please provide the German text you want me to translate. I will translate only the readable text, leaving any HTML tags, BBCode tags, and URLs as they are.
If the clamping screws are loosened, use a long wrench (SW 1 to grip the central screw and rotate the inner part into the desired position so that the 6mm tool can easily be fully inserted.
It is usually unfounded to be afraid of loosening or over-tightening the central screw while rotating the NW: Until the beginning of the central screw's torque range (100 Nm, if necessary, rotate the NW with a torque wrench, e.g. with a 70 Nm setting), nothing harmful can happen.
Once the measuring tool is fully inserted, tighten the clamping screws, remove the measuring tool (!!), and rotate the motor at least one full revolution of the NW.
Then, check and, if necessary, correct the setting as described, starting from the forward rotation of the motor.

Since the interpretation of the setting and the direction of correction are not immediately obvious, you can refer to the following scheme:
Tightening the clamping screws in the long holes of the gear wheel counterclockwise = later NW setting.
Tightening the clamping screws in the long holes of the gear wheel clockwise = earlier NW setting.

However, tightening the clamping screws in the right half of the long holes does not necessarily mean that the NW is actually "early" set:
If the gear wheel is positioned so that the NW gear wheel lags behind the KW gear wheel by one tooth, the clamping screws must be almost at the initial position of the long holes even when the NW is correctly set to compensate.
[b]Setting the "Pre-tension" of the PDE[/b]
First, remove the upper ZR protection and the valve cover.

In the case of the ASZ in the Polo 9N, the cover came off with approximately 2mm of the screw flange of the intake manifold and the AGR unit.
"Exactly right" would have been to remove the intake manifold, but a few strokes with a file on both parts solved the problem.

The PDE (Positive Displacement Engine) are set "at the bottom dead center" to a defined distance of the pump piston from the bottom of the high-pressure chamber.
Therefore, the PDE to be set must first be brought precisely to the bottom dead center (end of the stroke).
The workshop mounts a measuring device on the ZK (crankshaft) using a special holder for UT (ultrasonic testing).
The bottom dead center = maximum deflection of the rocker arm can also be determined differently by attaching a long "pointer" to the rocker arm. For example, place a 18mm ring spanner on the counter nut, insert a long (or extended) wrench into the adjustment screw, attach a wire to the rocker arm, etc. (see Appendix 2, Image 3).

Then, the engine is rotated so that the pointer strikes as far forward as possible (when installed transversely) or downwards.
[b]
Attention: If the shutdown does not occur at the end of the feed hub, then during the next motor run, the feed piston will hit the bottom of the PDE high-pressure room, causing the weakest link in the power transmission chain between the crankshaft and the PDE to fail. Whether this manifests as a cracked timing belt, a broken rocker arm, or the rocker arm shaft being torn out of the cylinder head, there is currently no information available. In any case, the damage would be very expensive, so it is important to exercise caution.
[b]
Before loosening the counter nuts of the PDE adjustment screws, make sure a torque wrench is available for re-tightening. If not, first mark the position of the nuts on the lever arm.

Loosen the counter nut of the activated PDE and turn the adjustment screw as far as possible into the lever arm until you feel a noticeable resistance: the PDE is at the lower stop.
From this position, turn the adjustment screw 225° out (half plus a quarter turn), and tighten the counter nut with 30 Nm or until the marking (Appendix 2, Image 4).
(Newer VAG instructions specify that the adjustment screw should only be turned out by
180 degrees
Instead of turning the 225° out, this applies to all PD engines, even though the previous setting for the same engine was 225°. The reasons for this change are not known.

Now, repeat the entire procedure on the remaining PD engines.

Before reassembling the valve cover, it is advisable to apply a small amount of permanent sealant around the two NW bearing supports, as PD engines are prone to slight oil leaks in this area, which should be avoided.

Then, install the valve cover and ZR protection, and check during a test drive whether the valve cover seal is actually tight.