Yamaha F75F - Checking the Fuel Injector; Checking the High-Pressure Fuel Pump

Fuel control unit and component
5-23
Checking the fuel injector
1. Check:
• Fuel injector operation
(using the YDIS
“Stationary test”)
No operating sound  Check the fuel in-
jector input voltage.
2. Measure:
• Fuel injector input voltage
Out of specification  Check the wire har-
ness for continuity.
a. Disconnect the fuel injector couplers
“a”.
b. Turn the engine start switch to ON,
and then
measure the input voltage
between the fuel injector coupler ter-
minal and ground.
c. Turn the engine start switch to OFF.
d. Connect the fuel injector couplers.
3. Measure:
• Fuel injector resistance
Out of specification  Replace.
a. Disconnect the fuel injector couplers.
b. Measure the fuel injector resistance.
c. Connect the fuel injector couplers.
Checking the high-pressure fuel
pump
1. Check:
• High-pressure fuel pump operation (usin
g
the YDIS “Stationary test”)
No operating sound  Check the high-
pressure fuel pump input voltage.
2. Measure:
• High-pressure fuel pump input voltage
Out of specification  Check the
wire har-
ness for continuity.
a. Disconnect the high-pressure fuel
pump coupler “a”.
b. Connect the tester probes to the termi-
nals of the high-pressure fuel pump
coupler, and
then measure the input
voltage within 5 seconds after turning
the engine start switch to ON.
Input voltage
12 V
Red/Yellow (R/Y)–Ground
Resistance (reference data)
12.20 
a
R/Y
Input voltage
12 V
Red/Yellow (R/Y)–Black (B)
(F75FEHT
, F100GEHT)
Red/Yellow (R/Y)–Blue (L)
(F75FET, F100GET)
a
R/Y
B
A