Arctic Cat M 8000, Service Manual

Page: 139 / 210

138
Throttle Position Sensor

NOTE: Two-stroke engines equipped with a throttle
position sensor have a protective feature called
“fail-safe” ignition timing preventing engine damage
should the TPS fail. If the TPS does fail, the engine
may run normally at low RPM but will run poorly at
high RPM allowing the operator to get the snowmo-
bile to safety with no engine damage. The engine will
continue to operate this way until the TPS is adjusted
or replaced.
CHECKING TPS

NOTE: If the snowmobile is in warranty, breaking
the seal on the idle screw jam nut or the Phillips-head
screws on the TPS will void warranty. If the TPS is
tested out of specification, the throttle body must be
replaced. If the snowmobile is out of warranty, pro-
ceed to Adjusting TPS.
6000
 NOTE: On the 6000, the TPS should only be
checked using the CATT II Tool. Instructions will be
included with the tool.
4000/8000
On the 4000/8000 before using the TPS adjustment tool,
verify its battery condition. The battery used in the tool is
a 9-volt battery. To check battery condition, use a digital
volt/ohmmeter set on DC volt scale. Test between the
adjustment tool black and red jacks. Insert the red lead of
the digital voltmeter into the red jack of the adjustment
tool and the black lead of the digital voltmeter into the
black jack of the adjustment tool. The green power light
of the analyzer should now be illuminated. If voltage is
found below 4.9 volts, replace the battery.

NOTE: The Test Harness must be plugged into the
analyzer for testing voltage. Always verify battery
voltage is at least 4.9 DC volts before testing TPS.
1. Using Throttle Position Sensor (TPS) Adjustment
Tool Kit, connect its wiring harness to the TPS.
2. Connect the red and black digital voltmeter leads to
the white and black jacks of the TPS adjustment tool.
3. Ensure that the throttle cable/control rod has the
proper amount of free-play.
4. With the throttle in the idle position, compare the
reading on the voltmeter to the chart. If the reading is
within prescribed specification, proceed to step 6.
5. Compress the throttle lever slowly to the full-open
position. The meter reading should show a smooth
rise in voltage all the way to the full-open position. If
the voltage seems to be erratic or doesn’t meet the
prescribed specification, repeat this procedure sev-
eral times to confirm results.

NOTE: If at any point throughout the throttle range
the meter reads no voltage (open), hold the throttle
lever in that position. If the voltage does not return,
the throttle body must be replaced.
6. If the full-open throttle voltage remains erratic or out
of specification, proceed to the appropriate Adjusting
TPS.
7. If the TPS is within the prescribed specification, dis-
connect the adjustment tool harness from the TPS.
Connect the snowmobile TPS harness to the TPS.

NOTE: Before installing the TPS harness connector,
apply dielectric grease to the connector pins.
ADJUSTING TPS

NOTE: Adjusting the TPS is for out of warranty
snowmobiles only.
6000

NOTE: On the 6000, the TPS should only be
adjusted using the CATT II Tool. Instructions are
included with the tool.
4000/8000
 NOTE: It is important that the throttle shaft is in
the completely closed position for this procedure.
1. Disconnect the throttle cable/control arm from the
throttle shaft.
2. Rotate the idle screw counterclockwise until it no
longer contacts the throttle shaft stop. The throttle
shaft should now be completely closed. Open the
throttle shaft by hand and release it, allowing the
shaft to gently snap closed several times.
3. Disconnect the TPS wiring harness from the TPS;
then using Throttle Position Sensor (TPS) Adjust-
ment Tool, connect the appropriate wiring harness to
the TPS. Connect the red and black digital voltmeter
leads to the white and black jacks of the TPS adjust-
ment tool.
4. While observing the digital voltmeter, slowly rotate
the sensor until the Full-Closed specification is
observed on the LCD of the multimeter. While hold-
ing the sensor in this position, tighten the two screws
which secure the sensor to the throttle body securely.
5. Gently snap the throttle open and closed several
times to check the TPS voltage. If it has changed
from the Full-Closed specification, loosen the two
screws which secure the sensor and make necessary
adjustments.
6. With the full-closed position set to specification,
rotate the idle screw clockwise until it contacts the
throttle shaft stop. Using the digital multimeter and
test harness, rotate the idle screw inward until the
Idle specification is observed.

NOTE: Rotate the idle screw past the recommended
voltage specification by two or three volts; then rotate
the idle screw counterclockwise to the correct idle
position voltage.
Model Idle Full-Open
8000 0.710-0.818 3.472-4.048
4000 0.646-0.754 3.472-4.485
Idle Full-Open
1.12v ± 0.075v 4.416v ± 0.15v