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The fuel injectors in the mk5/mk6 Jetta/Golf/JSW and Audi A3 TDI CBEA/CJAA or similar engines are piezoelectric injectors. For reference, here's a pic of the injector internals from user Dweisel: a piezoelectric element rapidly opens and closes a needle which sits in a nozzle to control fuel delivery. The Passat uses solenoid injectors and other than the bracket, the procedure is very similar. If you have a Passat and can add notes, pictures, or corrections specific to the Passat, please post in the forums to help improve this article!
NOTE: This was performed on my demo engine out of the car. If you can provide additional tips, corrections, or pictures showing this procedure in the car, please post in the myturbodiesel.com TDI forums and help improve the article! This demo engine was partially paid for with site donations, please use the donate button above so I can provide more great DIY!
Caution: Wipe down the area around the common rail and valve cover as you are working! You will open the valve cover and fuel system during this procedure and you don't want all that dust and dirt contaminating the oil and fuel system!
Remove the engine cover and grey sytrofoam damper. Disconnect the fuel injector, common rail fuel pressure sensor, and glowplug plugs. One of each of these is marked below. The glowplug plugs are pressed on so take not to damage the wiring - pull from the plug, not the wiring!
Loosen the fuel union nuts and set aside the injector hard lines. Note their positions. (This pic was done with common rail removal so ignore the other stuff). If you didn't clean before, clean now.
Cover the open fuel system with plastic.
Remove the allen head injector surround cover bolts and rotate them to the side. Remove the 2x 10mm nuts holding the fuel injector clamps. The injector is now loose. The sevice manual says you have to use a slide hammer where the fuel injector lines were attached but mine just came out with a gentle tug. (The engine was almost new)
If you're removing all the injectors, just remove them as a unit. If you wish to disconnect the fuel return line or a single injector, release the return line by pulling the center part up to release a tab while counterholding the side tabs down.
Note the copper o-ring at the botom. Make sure the old one is out before replacing them! If the copper o-ring is stuck, gently clamp it while twisting the injector body.
Before installing the injectors, use a plastic brush lubed with motor oil to clean the copper o-ring seat. VW has a special plastic guide sleeve T10377 to help slide the new o-ring over the tip of the injector, shown below. You can buy it from snap-on. When installing injectors, lightly lube the rubber o-ring with oil and gently twist the injector once it's in place to help seat the copper o-ring. The injector bracket should curve down like this.
The service manual says that you can't reuse injectors but this is incorrect. However, you must put them back in the original position or adapt each injector to their new slot if you switch them around. Using VCDS, go to the engine module>long adaptation and then enter the code on each injector under channels 71-74. Channel 71=inj #1, channel 72=inj #2, etc. Save it and the injectors are adapted. You must do this with new injectors as well.
8 metal fuel line unions: 18-20 ft-lb (25-28 Nm) (number depends on source so just don't kill it and deform the unions) - NOTE: install the lines without any stress! Remember to replace the black rubber dampers if they were removed.
8x 10mm injector bracket nuts: 7.3 ft-lb (88 inch lbs) (10 Nm)
10x allen head bolts for injector surround covers: 3.5 ft-lb (44 inch lbs) (5 Nm)
If you have any questions about this procedure or comments on this article for on your Audi A3, VW Jetta, Golf, or Sportwagen, please post your question in the myturbodiesel.com forums or search the site below: