Valtra VALMET 6000, Workshop Manual

Page: 404 / 1361

363
Model Code Page
34. Autocontrol---III
8. 11. 1990
6600E, 8100E 341 1
15. 6. 1992
Trouble shooting and repairs
(Computer---aided trouble shooting, see
Code 342
)
1. Checking and fitting sensors
A. Fitting speed sensors
--- Clean the sensor threads on the tractor.
--- Seek with a dial gauge the shortest distance between the
sensor and the impulse disc through the sensor hole (not
necessary for engine speed sensor. Pull the 4WD output shaft
outwards before measurement).
--- Apply Loctite 572 onto the threads and screw the sensor by
hand until the sensor touches the impulse disc or gear (do not
screw too hard because the impulse disc can be springy).
--- Then unscrew the sensors as follows:
Gengine speed sensor 1/3 of a turn
Grear axle sensor 1/4 of a turn
GPTO speed sensor 1/3 of a turn
Ggearbox speed sensor 1/10 of a turn
Gfront axle sensor 1/10 of a turn
--- Lock the sensor with a locking nut and connect wires.
--- Calibrate and check the speed sensors (see instr. B).
Check the engine rotation speed sensor (see instr. C ) and
check the PTO speed sensor (see instr. D )
N.B . The sensors should be checked with an oscilloscope if
necessary. The resistance of every speed sensors (not a
radar) is 1,0---1,10 k
Ω
--- When the sensor functions, fit a plastic tube onto the sen-
sor leads. Connect cable shoes to the sensors and protect
shoes with grease. Put the plastic tube onto the sensor and
warm it up until it is pressed tightly round the sensor
.
See fig-
ure M on page 340/4.
B. Calibrating the speed sensors
1. Drive the tractor onto the hard ground (free driving distance
about 50 m)
2. Select gear M2 , disengage diff. lock and 4WD (in M---posi-
tion). Select HARE---range for the quick shift gear and adjust
the engine revs to 1800 RPM with a hand throttle lever.
3. Press the distance---key two times and the display shows
text
CAL DIST
.
4. Drive the tractor straight ahead with the hand throttle lever.
5. Press SET ---key (display shows text DRIVE ). Continue
driving until the display is switched off and then started again
(=successful calibration).
6. If the display shows text
NO CALIB
(=signal from the radar
too weak), carry out a new test---driving. If the calibration fails
again, check the radar and its wiring.
7. If the display shows:
--- ERROR GB =gearbox speed sensor damaged
--- ERROR FA = front axle speed sensor damaged
--- ERROR RW = rear wheel speed sensor damaged
In this case, check the sensor in question and also its mount-
ing and wiring.
8. After successful calibration, change display to the calibrat-
ing mode for the hidden functions (see page 340/6 ) and
continue driving straight ahead.
9. Press once the SPEED---key, and the display shows the
radar speed
.
10. Press then twice the SPEED---key and the display will
show the gearbox speed which should be the same as the
radar speed (±0,1 km/h).
11. Press once again the SPEED ---key and the display will
show the
rear axle speed
which should be the same as the
previous speeds (±0,1 km/h).
12. Press once again the SPEED---key and the front axle
speed can be seen. It must be the same as the previous
speeds (±0,1 km/h).
13. Press the menu scanning key four times = radar speed.
Note! The calibrating mode can be left by switching off the
current.
C. Sensor for engine revs
The engine RPM sensor can be checked by pressing the
RPM---key until the display shows the engine revs. The dis-
play reading must be about the same as the rev counter read-
ing (± 50 RPM) in the instrument panel.
Checking can be carried out more accurately by adjusting the
engine revs in the display to 1874 r/min at which time the PTO
shaft rotating speed must be 540 r/min which can be seen in
the display by pressing the RPM---key.
If the display does not show the engine RPM, check the sen-
sor and its wiring. The resistance of the sensor must be
between 1,0---1,10 k
Ω
(pins A1C/31, 12). If the sensor is OK,
the possible fault can be a faulty ECS or the display unit is
defective. Also the impulse disc can be damaged.
D. PTO speed sensor
Engage the 540 r/min PTO. Press the RPM---key until the dis-
play shows the PTO shaft speed. Adjust the engine revs so
that the rev counter indicator in the instrument panel is at the
540 mark. Now the AC---III display should also show 540 RPM
(± 50 RPM). In the same way, check the 1000 r/min PTO.
More accurately the display reading for the PTO speed can be
checked by measuring the PTO shaft speed with a separate
tachometer. Then compare the tachometer reading with the
reading in the the AC---III display.
If the display does not show the PTO RPM, check the sensor
and its wiring. The resistance of the sensor must be between
1,0---1,10 k
Ω
(pins A1C/28, 11). If the sensor is OK, the poss-
ible fault can be a faulty ECS or the display unit is defective.
Also the impulse disc can be damaged. N.B. Check that the
emergency plug is fitted in the rear socket.