Volkswagen Workshop Service and Repair Manuals

Removing and installing unit injector

Special tools and workshop equipment required

t	Universal dial gauge bracket -VW 387-

t	Allen key, long reach -T10054-

t	Puller -T10055-

t	Torque wrench -V.A.G 1331-

t	Dial gauge

t	G 000 100 grease

Note

For introduction of extended service interval, adjusting screw -1- and ball head pin -2- of unit injector have been modified. On older engines with no extended service interval, a mixture of both types of unit injector may be installed. Removing –  Remove the upper toothed belt guard and the cylinder head cover. –  Turn crankshaft until the cam pair point evenly upwards for the unit injector which is to be removed.

–  Loosen lock nut of adjuster screws -1- and screw adjuster screws out until the relevant rocker arm lies against the plunger spring of the unit injector. –  Remove rocker arm securing bolts -2- (from outwards to inwards) with socket 3410 and take rocker arm shaft off. –  Remove tensioning block securing bolt -3- with special wrench, long reach -T10054- and remove the block. –  Lever connector off unit injector with a screwdriver. To avoid canting, support opposite side of connector with light finger pressure.

–  Seat the puller into the slot on the side of the unit injector instead of the tensioning block. –  Pull unit injector out of cylinder head seat with gentle taps. Installing   Note t  If a new unit injector is installed, the appropriate adjustment screw in the rocker arm must also be renewed. t  Each time work is performed which requires the unit injector to be adjusted, the adjustment screw in the rocker arm and also the unit injector ball pin must be cleaned and checked for signs of wear. If wear is evident the ball pin and the adjustment screw must be replaced. t  On older version of unit injector, lubricate contact surface between ball pin and adjusting screw with G 000 100 grease. t  New unit injectors are supplied with O-rings and heat shield seal. –  Heat insulating seal and O-rings must be renewed if old unit injector is reused → Chapter. –  Before installing the unit injector, check that the three O-rings, the heat shield seal and securing clip are seated correctly.   Note The O-rings must not be twisted. –  Oil the O-rings and fit the unit injector into the cylinder head extremely carefully. –  Push the unit injector evenly into the cylinder head onto its limit stop. –  Fit the tensioning block into the slot on the side of the unit injector.   Note If the unit injector is not at right angles to the tensioning block the securing bolt may loosen and this can damage the unit injector or the cylinder head. –  Therefore align the unit injector as follows. –  Screw new securing bolt into clamping block, but do not tighten (it must still be possible to turn the unit injector slightly). –  Now align unit injector perpendicular to camshaft bearing pedestals. –  Check dimension “a” from outer edge of cylinder head to rounded edge of unit injector with a vernier gauge (measuring range at least 400 mm).   Note Gradual introduction of unit injector with new solenoid valve nut. A mixture of both types is permissible providing dimension “a” is reached.

Unit injector with old solenoid valve nut

Cylinder		Dimension “a”
1		332.2 ± 0.8 mm
2		244.2 ± 0.8 mm
3		152.8 ± 0.8 mm
4		64.8 ± 0.8 mm

Unit injector with new solenoid valve nut

Cylinder		Dimension “a”
1		333.0 ± 0.8 mm
2		245.0 ± 0.8 mm
3		153.6 ± 0.8 mm
4		65.6 ± 0.8 mm

Continuation for all unit injectors –  Align unit injector if necessary and tighten securing bolt as follows: –  Tighten securing bolt to 12 Nm and turn 270° (3/4 turn) further (turning further can be done in several stages).

–  Fit rocker arm shaft and tighten new securing bolts as follows: –  First tighten inner bolts -2- then outer bolts -1- by hand. Then using same sequence, tighten to 20 Nm and turn 90° (1/4 turn) further.

–  Fit the dial gauge onto the adjustment screw of the unit injector as shown. –  Turn crankshaft in direction of engine rotation until roller of rocker arm is located at tip of drive cam. Roller side -arrow A- positioned at highest point, dial gauge -arrow B- positioned at lowest point. –  Remove dial gauge. –  Now turn the adjuster screw into rocker arm until significant resistance can be felt (unit injector is at limit stop).

–  Turn adjuster screw 180° back off stop. –  Hold adjustment screw in this position and tighten the lock nut to 30 Nm. –  Push on unit injector connector and install cylinder head cover and toothed belt guard.