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

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

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

Injection is only possible as long as the injection rocker arm transmits power to the PDE with its rising cam.
Due to the shape of the rising flank, the rate of injection is determined.
Each adjustment of the camshaft therefore not only shifts the fuel mixture, but also the possible time window for an injection and the course of the flow rate relative to the camshaft position.
Similar to a distributor pump that is set too late, for example, a PD-NW that is set too late at the beginning of the target injection (in the Pmax range) can delay the actual injection start.
However, in the PD engine, the injection is terminated at the normal time, thus reducing the injection volume compared to the target value, while the VP 37 continues to inject the target volume - but only too late.

Practical experience with an ASZ engine revealed that a change in the factory-specified camshaft timing of approximately 3°KW towards earlier timing (as described in the following setting: according to the marker, the KW in the camshaft position is located on the gearbox flange) allows the engine to run smoothly during full-throttle acceleration in the upper RPM range, while with the factory setting, it became slightly sluggish above approximately 3500 rpm.

The effects of a misaligned camshaft should feel similar in all PD engines.
So, if a PD-TDI, for example, is accelerating at full throttle in 3rd gear, If the engine's power output drops significantly, somewhere between 3,000 and 4,000 RPM, and there are noticeable gaps in the power delivery, you should also consider the possibility of an "incorrect setting" in the engine control unit, in addition to issues like LMM and turbocharger problems, etc.

The NW setting can also be used, after appropriate trials, to specifically influence the engine's performance characteristics (within certain limits).
Even a slight increase in performance at higher engine speeds appears possible with a particularly "early" setting, more details under
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The position of the camshaft relative to the crankshaft can be displayed using OBD (e.g., with VCDS), and the corresponding measurement value is called "Synchronization Angle". In this engine, you can find it in the measurement block 4 of the engine control unit.

More details about the synchronization angle:
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It is possible that the "setting according to guideline" which reduces performance, using a marking tool on the ZR wheel (instead of using the OT marking on the gearbox flange), was intentionally implemented for emission reasons.
If that is correct (unfortunately, there is no confirmed information available), changing the NOx setting in order to improve engine smoothness could potentially lead to exceeding emission limits and, consequently, the revocation of the operating permit.

The exam and, if necessary, Fine-tuning can be achieved by a DIY enthusiast without specialized, exotic tools, if one improvises.
Also, adjusting the PDE is relatively straightforward – the biggest individual task is removing and reattaching the valve cover.
With these two works, you essentially have complete control over the mechanical engine settings for the 1.9L and 2.0L PD engines.

To perform both tasks, the following minimal equipment is required:
-> a marking tool with a length of at least 7 cm and a diameter of 6 mm, as well as other tools with a smaller diameter are also helpful. The marking tools should be designed at the "handle end" to ensure that they cannot fall into the lower ZR channel for safety reasons.
-> Torque wrench and ratchet with 10, 13 mm and 18 mm nuts, alternatively ring spanners, marking pin and a ruler
-> 6 mm Allen wrench
-> Tool for removing the upper cover and, if necessary, for removing interfering air intake ducts; the openings should then be sealed with verschandeln cloths.
-> a flat surface that allows the vehicle to be pushed forward and backward for at least 1 meter.

To avoid having to rotate the engine by pushing the vehicle, it is recommended to use a suitable wrench to rotate the crankshaft. If access to the crank sprocket is difficult, the sliding method with two assistants is recommended.

To check the NW setting of the 1.9/2.0l 8V TDIs, first remove the upper ZR protection and expose the OT leveling opening on the engine-gearbox flange.
Then look for a marking "3Z" or "4Z" on the part of the upper ZR protection that faces the engine block -> Image 1, here the relief lettering is highlighted for clarification.
Instead of the 4Z marking, a 3Z marking may be present in the tension roll / flange area.
In the engine's test position = the 1st cylinder's OT (crankshaft centerline) is located with the notched window in the NW (crank) wheel's tooth section, approximately at the 11 o'clock position (Figure 2), and one of the Hall sensor markings (two small metal tabs on the NW wheel's motor-side edge) is on the Z-mark. The tip of the Z-marking is, in this case, pointing towards the center between the sheet edges (Appendix 2, Figure 1).

A difference between factory-made and Due to the specific requirements of the workshop setup and this instruction, it is possible that the crankshaft (KW) does not align perfectly with the timing mark (OT) on the crankshaft wheel (ZR) when set using the "crankshaft stop," but instead is slightly off, approximately the 3° mentioned earlier.
This difference between the zero-position with the crankshaft stop and the OT mark during the adjustment of the engine control (NW gear) is the cause of the aforementioned. Differences in engine performance characteristics.
To install the crankshaft stop, the belt wheel / vibration damper must be detached from the crankshaft and the lower crankshaft cover must be removed.

To check the NW (No-Load) setting, bring the engine from a forward rotation to the OT (Optimal Turning) of the 1st cylinder. The NW should then be in the specified inspection position, and ideally, the 6 mm marking tool should be able to be fully inserted, i.e., 6 cm deep (Appendix 2, Image 2).
If not, you can try using thinner marking tools to see if the NW is at least near the marking position.

Note: Behind the clearly visible marking hole on the outer part of the NW wheel, there is the actual 6mm marking round hole on the inner part of the NW wheel.
Only if the hole aligns perfectly 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!

Warning: If the ZR has been freed from a backward rotation, the normal forward side of the KW is no longer properly tensioned, and the KW (even with correct NW settings!) is more or less facing the OT, which in effect looks like an "early" setting of the NW.

If the 6mm marking tool for the NW cannot be easily inserted when performing KW (or when the KW is marked), then the setting is incorrect. To correct this, the gear and inner part of the NW wheel must be rotated relative to each other.
To do this, you need to loosen the 3 clamping screws by approximately ½ turn.

Warning:
When tightening the 3 clamping screws later after adjustment, the torque of 25 Nm should be strictly observed with a cold engine (2.0l 16V TDI: 30Nm).
If you don't have a torque wrench, you should mark the position of the screws before loosening them, for example, by drawing a line across the screw head with a ruler, which points exactly to the center of the central screw. When tightening to the final stage, you turn the clamping screws so that the markings point back to the center of the central screw.

Once the clamping screws are loosened, use a sufficiently long ring spanner (SW 1 on the central screw and rotate the inner part into the desired position so that the 6mm tool can be easily inserted completely.
It is often unfounded: Excessive tightening of the central screw during the turning of the NW is usually unnecessary: Until the beginning of the central screw's torque range (100 Nm, if necessary, tighten the NW with a torque wrench, for example, with a setting of 70 Nm), nothing harmful can happen.
Is the marking tool fully retracted, tighten the clamping screws, remove the marking tool (!!) and turn the engine at least 1 full revolution.
Subsequently, control the setting as described, starting from the forward rotation of the engine, and make any necessary corrections.

Since the interpretation of the attitude and the correction direction are not entirely obvious, one can refer to the following scheme:
Tightening the set screws in the long holes of the gear wheel, in the counter-clockwise direction = subsequent NW (nut) adjustment.
Tightening the set screws in the long holes of the gear wheel, in the clockwise direction = restoring the previous NW (North-West) setting.

However, for example, Tightening screws in the right half of the long holes does not necessarily mean that the NW is actually "early".
If the ZR is set up so that the NW gear "lags behind" the KW gear by 1 tooth, then the clamping screws must be close to the initial position of the long holes even when the NW gear is correctly adjusted.

To adjust the "pre-tension" of the PDE , first remove the upper ZR protection and the valve cover.
When working on the ASZ in the Polo 9N, the cover detached from the screw flange of the intake manifold and the AGR unit, approximately 2mm.
"Actually, you should have unscrewed the intake manifold, but a few strokes with the file on both parts also solved the problem."

The PDEs are set "at the lower dead point" to a defined distance between the pump plunger and the bottom of the high-pressure chamber.
Therefore, the PDE that needs to be set must first be precisely brought to the lower dead point (end of the stroke).
The workshop installs a measuring device, specifically a measuring gauge, on the ZK (presumably a component) using a special holder for UT (presumably Ultrasonic Testing) inspection.
The lower dead point = maximum displacement of the rocking lever can also be determined in other ways, for example, by attaching a long "pointer" to the rocking lever. For example, place the 18mm ring spanner on the locking nut, insert a long (or extended) wrench into the adjustment screw, attach a wire to the lever arm, etc. (see Appendix 2, Image 3).

Then the engine is rotated so that the pointer strikes as far forward as possible (when installed sideways) or downwards.

Warning: If the shutdown does not occur at the end of the feed cylinder, then during the next motor run, the feed piston will hit the bottom of the PDE high-pressure chamber, causing the weakest link in the crankshaft-to-PDE power transmission chain 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 on this. In any case, the damage would be very costly, which is why one should exercise due diligence.

Before loosening the PDE adjustment screws, it is important to ensure that a torque wrench is available for re-tightening. If not, first mark the position of the nuts on the lever.

Loosen the locking nut of the actuated PDE and turn the adjustment screw further into the lever until you feel a noticeable resistance: the PDE is at the bottom stop.
From this position, unscrew the adjustment screw by 225° (half plus a quarter turn), and tighten the locking nut with 30 Nm or until the mark (Appendix 2, Figure 4).
(Recent VAG instructions specify that the adjustment screw should only be turned 180° instead of 225°. This applies to all PD engines, even though the same engine previously specified an adjustment of 225°. The reasons for this change are not known here.)

That's all for the first PDE. Now, repeat the entire exercise with the remaining PDEn.

Before reassembling the valve cover, it is advisable to apply a small amount of permanent sealant around the two NW (north-west) bearing saddles. This is because PD (Porsche Diesel) engines are prone to slight oil leaks in this area, which should be avoided, especially in the ZR (cylinder head) area.

Then install the valve cover and ZR (Zylinder) protection, and during a test drive, check to make sure the valve cover gasket is actually sealed properly.