Fail-Safe Function - Suzuki VZ800 Service Manual

5-20 FI SYSTEM

FAIL-SAFE FUNCTION

FI system is provided with fail-safe function to allow the engine to start and the motorcycle to run in a mini-
mum performance necessary even under malfunction condition.
ITEM
IAP sensor
TP sensor
ECT sensor
IAT sensor
Ignition signal
Injection signal
Secondary throttle valve
actuator
STP sensor
Gear position signal
Heated oxygen sensor
(E-02, 19, 24)
PAIR control solenoid valve
The engine can start and can run even if the above signal is not received from each sensor. But, the engine
running condition is not complete, providing only emergency help (by fail-safe circuit). In this case, it is nec-
essary to bring the motorcycle to the workshop for complete repair.
When two ignition signals or two injector signals are not received by ECM, the fail-safe circuit can not work
and ignition or injection is stopped.
FAIL-SAFE MODE
Intake air pressure is fixed to 760
mmHg.
The throttle opening is fixed to full
open position.
Ignition timing is also fixed.
Engine coolant temperature value is
fixed to 80 °C (176 °F).
Intake air temperature value is fixed
to 40 °C (104 °F).
#1 Ignition-off and #1 Fuel-cut
#2 Ignition-off and #2 Fuel-cut
#1 Fuel-cut
#2 Fuel-cut
Secondary throttle valve is fixed to
full close position. When motor dis-
connection or lock occurs, power
from ECM is shut off.
Secondary throttle valve is fixed to
full close position.
Gear position signal is fixed to 5th
gear.
Fuel-air compensation ratio is fixed
to normal condition.
ECM stops controlling PAIR control
solenoid valve.
STARTING RUNNING
ABILITY ABILITY
"YES" "YES"
"YES" "YES"
"YES" "YES"
"YES" "YES"
"YES" "YES"
#2 cylinder can run.
"YES" "YES"
#1 cylinder can run.
"YES" "YES"
#2 cylinder can run.
"YES" "YES"
#1 cylinder can run.
"YES" "YES"
"YES" "YES"
"YES" "YES"
"YES" "YES"
"YES" "YES"