I like the idea of being able to set the timing mechanically, but seems to me like more work than its worth. If the timing is good to begin with, and you have the proper lock tools, you should be able to replace the belt with out messing the timing up. It should at least start and run well enough to get you to a VAG-COM...The actual timing changes with fuel and engine temperature...Setting the Injection Timing - Injector Pump Mechanical Adjustment - A VW specific scan tool such as VAG-COM is required for this procedure. It cannot be done by any other method. The mechanical adjustment technique used for previous generations of VW diesels, which used a mechanical fuel pump without electronic control, is not suitable for the electronically controlled TDI injector pump.
With the engine warmed up and idling, connect the diagnostic tool, and select the engine control module. At this point, one of two different procedures is necessary, depending upon whether you have the proper factory service manual for your particular vehicle.
If you have the factory service manual, select "Measuring Blocks", group 0, then select "Basic Settings". The glow plug indicator lamp will begin flashing at this time (this is normal). Do NOT forget to go into "Basic Settings" because this procedure is completely invalid if measurements are taken outside of "basic settings". Take note of the 2nd and 9th numbers in the display. Locate the chart in the factory service manual which shows the proper relationship between these two numbers. Go across the chart with the 9th number then up the chart with the 2nd number and make sure it is within the shaded area. It has been found through experience that these engines have better cold starting characteristics if the setting is within the upper half of the shaded area. If it is good ... don't do anything further. If the second number is below the recommended range, you need to make a mechanical "advance" adjustment (see below). If the second number is above the recommended range, you need to make a mechanical "retard" adjustment (see below).
If you don't have the factory service manual, select "Measuring Blocks", and go to group 4. Do NOT use "basic settings" for this method. The displays show the requested injection timing, the actual measured injection timing, and the duty cycle of the advance solenoid. At warm idle in neutral, requested timing should be between 0.4 and 2.0 degrees BTDC. If the actual timing is not more than roughly 3.0 degrees BTDC, and the duty cycle of the advance solenoid is not more than 10%, the timing is good ... don't do anything further. If actual timing is more than 3.0 degrees BTDC, you need to make a mechanical "retard" adjustment. If the duty cycle is more than 10%, you need to make a mechanical "advance" adjustment.
If you have an A3 or B4, you need to rotate the body of the injector pump "forward" to retard the timing and "backward" to advance the timing. Stop the engine. Remove the upper timing belt cover. Rotate the engine by hand (shifting trans into 5th gear and pushing the whole car works) such that the two nuts at the rear and bottom of the injector pump flange can be reached through the access holes in the pump pulley. Loosen these two nuts by 1 turn, loosen the bolt at the top front of this flange 1 turn (accessed from outside, not within the pulley). Loosen the bolt located at the opposite end of the pump below the four injector lines. With a 17mm wrench, loosen by 1/2 turn the injector lines on the end of the pump. Now you can rotate the entire pump housing in the required direction (make VERY SMALL adjustments) then tighten and reassemble everything and recheck the timing.
Topic: What is initial injection timing setting on 98 AHU TDI (Read 16865 times)
