3-37
3
735-476B
COMPONENTS
The main components of the APV system are the following.
A. Lighting Coil
B. Voltage Regulator/Rectifier
C. ECU
D. Servomotor
E. Power Valve Cables
F. Power Valves
Lighting Coil
The AC current generated by the lighting coil flowing to
the regulator/rectifier is the power source for the APV
system.
Voltage Regulator/Rectifier
The AC current from the power coil first enters the regulator/
rectifier changing from AC current to DC current. Since the
APV circuit cannot use pulsating DC current, it must be con-
verted (by the condenser) to straight DC current. AC current
enters the ECU from the lighting coil and is changed from
AC to DC current by a rectifier located within the ECU.
ECU
The computer within the ECU has been programmed to
raise and lower the power valves at 4500 RPM. When
this RPM is reached, DC current is routed to the servo-
motor by the ECU.
Servomotor
The servomotor consists of two circuits. One circuit is a
DC circuit operating the DC motor within the servomo-
tor, and the other is a potentiometer measuring the pulley
position based on voltage.
The computer within the ECU has been programmed to
operate the servomotor between a low and high voltage
range. If voltage is not within the range, the computer
will shut down the APV circuit. The computer will then
make a total of three more attempts to cycle the power
valves. If the correct voltage or pulley position isn’t seen,
the APV circuit is shut down and no more attempts will
be made until the engine is shut down and restarted.
Exhaust Valve Cables
The exhaust valves are connected to the actuating cables
and, along with the return springs, are contained inside the
APV housing on the exhaust side of each cylinder. The
other end of the actuating cable is connected to the servo-
motor.
OPERATION
At idle and low speed operation, the exhaust valves are held
in the “low port” position by the return spring. When
engine RPM reaches a predetermined point, the ECU will
send a signal to the servo which cycles and pulls the
exhaust valves into the up or “high port” position.
If the servomotor cycles the exhaust valves as explained
above, the exhaust valve circuit is operating satisfacto-
rily. If the servomotor makes no attempt to open the
valves or if the servomotor attempts to cycle the valves
three times (then stops working), a problem exists and it
must be corrected.
Servomotor Cycles Three Times
In this situation the ECU computer has been programmed
with a voltage range (low and high) that the servomotor
must operate within. If the servomotor is put under too
much load, its resistance goes up and may exceed the
range upper limit. It will then stop and attempt two more
times. If the resistance still is too high, it shuts down.
If the servo is commanded to move but the potentiometer
output voltage does not change, an error occurs and the
check engine light will flash a trouble code.
Improper servomotor position sensing is normally caused
by one or more of the following:
A. Incorrect exhaust valve cable length (too long or
too short).
B. Exhaust valve cable(s) sticking, broken, or dis-
connected at pulley.
C. Exhaust valves sticking.
D. Exhaust valve spring(s) weak or broken.
Check each of the above probable causes in the order
given to locate the problem of the servomotor cycling
three times in succession; then shutting down.
Check for correct exhaust valve cable length specifica-
tions for model being worked on in this section.
Servomotor Makes No Attempt To
Cycle
If when running the engine the servomotor makes no
attempt to operate, this is caused by one or more of the
following:
A. Bad connection from the wiring harness and con-
nector from the lighting coil to the ECU, or from
the ECU to servomotor.
B. ECU output to servomotor is too low.
C. Servomotor failure.
D. Blown fuse.
Summary of Contents for Sno Pro 120
Page 20: ...1 18 NOTES ...
Page 29: ...2 9 2 570ENG12 ...
Page 39: ...2 19 2 500CC2A_12 ...
Page 45: ...2 25 2 NOTES ...
Page 47: ...2 27 2 800_12_2 ...
Page 61: ...2 41 2 Engine Torque Patterns 1100 cc 1100TorquePattern12 ...
Page 63: ...2 43 2 1100ccZ1RV10 ...
Page 81: ...2 61 2 1100ccZ1RV10 ...
Page 82: ...2 62 Engine Torque Patterns 1100 cc 1100TorquePattern12 ...
Page 141: ...2 121 2 SNO2152 ...
Page 142: ...2 122 SNO2153 ...
Page 180: ...3 18 0742 314 0746 520 F5 LXR 800 cc ...
Page 204: ...3 42 NOTES ...
Page 260: ...5 26 Troubleshooting Servomotor SERVO1A12 ...
Page 261: ...5 5 27 SERVO2rv ...
Page 264: ...Magneto 0746 255 1 ...
Page 266: ...Main Harness p n 1686 603 F5 LXR 0746 249 3 ...
Page 269: ...Main Harness p n 1686 588 F 800 M 800 XF 800 0746 242 6 ...
Page 270: ...Main Harness p n 1686 611 TZ1 Turbo LXR LTD 0746 253 7 ...
Page 271: ...Main Harness p n 1686 610 TZ1 TZ1 LXR 0746 252 8 ...
Page 272: ...Main Harness p n 1686 613 Bearcat Z1 XT GS p n 1686 615 Bearcat Z1 XT LTD 0746 511 9 ...
Page 273: ...Main Harness p n 1686 578 Sno Pro 120 10 0744 204 ...
Page 274: ...Ignition Main Harness p n 1686 628 Sno Pro 500 11 0745 605 ...
Page 275: ...Ignition Main Harness p n 1686 657 Sno Pro 600 12 0746 250 ...
Page 276: ...0745 601 13 Console Harness p n 1686 631 TZ1 LXR TZ1 Turbo LXR LTD ...
Page 277: ...Hood Harness p n 1686 638 F 800 M 800 XF 800 0746 243 14 ...
Page 278: ...Console Harness p n 1686 633 Bearcat 570 F570 T570 0746 238 15 ...
Page 279: ...Console Harness p n 1686 634 F5 LXR 0746 240 16 ...
Page 280: ...Hood Harness p n 1686 639 F 1100 Turbo M 1100 Turbo HCR XF 1100 Turbo 0746 246 17 ...
Page 282: ...0746 254 19 Console Harness p n 1686 547 Bearcat Z1 XT GS p n 1686 549 Bearcat Z1 XT LTD TZ1 ...
Page 283: ...Hood Harness p n 1686 587 Sno Pro 500 20 0744 201 ...
Page 285: ...Passenger Seat Harness p n 1686 570 22 0744 197 ...
Page 286: ...Handlebar Harness p n 1686 636 F 800 M 800 XF 800 p n 1686 654 M 800 HCR 0746 244 23 ...
Page 287: ...Handlebar Harness p n 1686 537 Bearcat 570 F570 T570 0746 239 24 ...
Page 288: ...Handlebar Harness p n 1686 574 F5 LXR 0744 189 25 ...
Page 289: ...Handlebar Harness p n 1686 637 F 1100 Turbo M 1100 Turbo XF 1100 Turbo 0746 247 26 ...
Page 290: ...Handlebar Harness p n 1686 590 Sno Pro 500 27 0744 200 ...
Page 291: ...Handlebar Harness p n 1686 656 M 1100 Turbo Sno Pro HCR 28 0746 510 ...
Page 292: ...Misc Groomer Special p n 1686 645 p n 1686 646 p n 1686 647 p n 1686 648 29 0746 241 ...
Page 460: ...8 26 0744 930 ...