YAMAHA YZF-R7 1999 Owners Manual

6 - 6
EFI

ELECTRONIC FUEL INJECTION
Order Job/Part Q’ty Remarks
13 Gasket 4
14 Spacer 16
For installation, reverse the removal
procedure.

6 - 7
EFI

ELECTRONIC FUEL INJECTION
Order Job/Part Q’ty Remarks
Removing the injector 1 and throttle
body
Remove the parts in the order listed.
1 Negative pressure hose 1
2 Pressure regulator 1
3 Union bolt 1
4 Washer 2
5 Injector fuel pipe 1 1
6 Injector fuel pipe 2 1
7 Washer 1
8 Fuel distributor 1
9 Injector 1 4
10 O-ring 4
11 Seal 4
12 Seal 4
13 Rear connecting plate 1

6 - 8
EFI

ELECTRONIC FUEL INJECTION
Order Job/Part Q’ty Remarks
14 Throttle position sensor 1
15 Throttle cable holder 1
16 Starter link lever screw 4
17 Starter link 1
18 Starter link lever 4
19 Front connecting plate 1
20 Throttle body 4
21 Starter plunger 4
22 Air screw 4
For installation, reverse the removal
procedure.

6 - 9
EFI

ELECTRONIC FUEL INJECTION
ACHTUNG:CAUTION:

The throttle bodies should not be disas-
sembled unnecessarily.
CHECKING THE INJECTOR
1. Check:
• injector 1
• injector 2
Damage
®
Replace.
CHECKING THE THROTTLE BODY
1. Check:
• throttle body
Cracks/damage
®
Replace the throttle
body assembly.
2. Check:
• fuel passages
Obstruction
®
Clean.
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a. Wash the throttle body in a petro-
leum-based solvent.
Do not use any caustic carburetor
cleaning solution.
b. Blow out all of passages with com-
pressed air.
s s s s s s s s s s s s s s s s s s s s s s s s s s s

6 - 10
EFI

ELECTRONIC FUEL INJECTION
CHECKING THE PRESSURE REGULATOR
1. Check:
• pressure regulator
Damage
®
Replace.
EAS00502
CHECKING AND ADJUSTING THE
THROTTLE POSITION SENSOR
NOTE:

Before adjusting the throttle position
sensor, the engine idling speed should
be properly adjusted.
1. Check:
• throttle position sensor
(installed on the throttle body)
t t t t t t t t t t t t t t t t t t t t t t t t t t t
a. Disconnect the throttle position sen-
sor coupler from the throttle position
sensor.
b. Connect the pocket tester (
W

´
1k) to
the throttle position sensor.
c. Measure the maximum throttle posi-
tion sensor resistance.
Out of specification
®
Replace the
throttle position sensor.
Positive tester probe
®

blue terminal
1
Negative tester probe
®

black/blue terminal
2
Maximum throttle position
sensor resistance
4.0 ~ 6.0 k
W
at 20 ˚C (68 ˚F)
(blue — black/blue)
B/LYL
231

6 - 11
EFI

ELECTRONIC FUEL INJECTION
d. Connect the pocket tester (
W

´
1k) to
the throttle position sensor.
e. While slowly opening the throttle,
check that the throttle position sensor
resistance is within the specified
range.
NOTE:

Check mainly that the resistance
changes gradually when turning the
throttle, since the readings (from closed
to wide-open throttle) may differ slightly
from those specified.
Out of specification or the resistance
changes abruptly
®
Go to step 2
below.
s s s s s s s s s s s s s s s s s s s s s s s s s s s
Positive tester probe
®

yellow terminal
3
Negative tester probe
®

black/blue terminal
2
Throttle position sensor resis-
tance
(520 ~ 900
W
) ~ (4.0 ~ 6.0 k
W
)
at 20 ˚C (68 ˚F)
(yellow — black/blue)
2. Check:
• throttle position sensor
(removed from the throttle body)
t t t t t t t t t t t t t t t t t t t t t t t t t t t
a. Disconnect the throttle position sen-
sor coupler from the throttle position
sensor.
b. Remove the throttle position sensor
from the throttle body.
c. Connect the pocket tester (
W

´
1k) to
the throttle position sensor.
Positive tester probe
®

blue terminal
1
Negative tester probe
®

black/blue terminal
2
B/LYL
231

6 - 12
EFI

ELECTRONIC FUEL INJECTION
d. Measure the maximum throttle posi-
tion sensor resistance.
Out of specification
®
Replace the
throttle position sensor.
e. Connect the pocket tester (
W

´
1k) to
the throttle position sensor.
f. While slowly opening the throttle,
check that the throttle position sensor
resistance is within the specified
range.
The resistance does not change or it
changes abruptly
®
Replace the
throttle position sensor.
The slot is worn or broken
®
Replace
the throttle position sensor.
NOTE:

Check mainly that the resistance
changes gradually when turning the
throttle, since the readings (from closed
to wide-open throttle) may differ slightly
from those specified.
s s s s s s s s s s s s s s s s s s s s s s s s s s s
Maximum throttle position
sensor resistance
4.0 ~ 6.0 k
W
at 20 ˚C (68 ˚F)
(blue — black/blue)
Positive tester probe
®

yellow terminal
3
Negative tester probe ®
black/blue terminal 2
Throttle position sensor resis-
tance
0 ~ 5 ± 1.0 kW at 20 ˚C (68 ˚F)
(yellow — black/blue)

6 - 13
EFIELECTRONIC FUEL INJECTION
3. Adjust:
• throttle position sensor angle
t t t t t t t t t t t t t t t t t t t t t t t t t t t
a. Disconnect the throttle position sen-
sor coupler from the throttle position
sensor.
b. Connect the pocket tester (W ´ 1k) to
the throttle position sensor.
c. Measure the throttle position sensor
maximum resistance.
d. Calculate the throttle position sensor
maximum resistance when the throt-
tle is fully closed.
Example:
If the maximum resistance = 5 kW, then
the throttle position sensor’s maximum
resistance when the throttle is fully
closed should be:
5 kW ´ (0.13 ~ 0.15) = 650 ~ 750 W
Lift the throttle body assembly slightly
out of the intake manifolds.
Loosen the throttle position sensor
screws 4.
Connect the pocket tester (W ´ 100) to
the throttle position sensor.
e. Adjust the throttle position sensor
angle so that the measured resistance
is within the specified range.
After adjusting the throttle position sen-
sor angle, tighten the throttle position
sensor screws.
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Positive tester probe ®
blue terminal 1
Negative tester probe ®
black/blue terminal 2
Throttle position sensor maximum
resistance (throttle is fully closed) =
Maximum resistance ´ (0.13 ~ 0.15)
Positive tester probe ®
yellow terminal 3
Negative tester probe ®
black/blue terminal 2
Throttle position sensor resis-
tance
650 ~ 750 W
(yellow — black/blue)
B/LYL
231
4

4

6 - 14
EFIELECTRONIC FUEL INJECTION
CHECKING THE FUEL PUMP AND
PRESSURE REGULATOR OPERATION
1. Check:
• pressure regulator operation
t t t t t t t t t t t t t t t t t t t t t t t t t t t
a. Remove the fuel tank and air filter
case cover.
Refer to “FUEL TANK AND AIR FIL-
TER” in chapter 3.
b. Disconnect the nagative pressure
hose 1 from the pressure regulator
at the joint.
c. Disconnect the injector fuel pipe 3 2
from the fuel distributor.
d. Connect the mity vac 3 onto the neg-
ative pressure hose from the pressure
regulator.
e. Install the pressure gauge 4 and
adapter 5 with the washers and
injector fuel pipe 3 onto the fuel dis-
tributor.
f. Install the fuel tank.
Refer to “FUEL TANK AND AIR FIL-
TER” in chapter 3.
g. Start the engine.
h. Measure the fuel pressure.
Mity vac
90890-06756
Pressure gauge
90890-03153
Adapter
90890-03151
T R..
Adapter
30 Nm (3.0 m • kg, 22 ft • lb)
Fuel pressure
250 ~ 260 kPa
(2.5 ~ 2.6 kgf/cm
2,
35.6 ~ 37.0 psi)

6 - 15
EFIELECTRONIC FUEL INJECTION
i. Use the mity vac to adjust the fuel
pressure in relation to the vacuum
pressure as described below.
NOTE:
The vacuum pressure should not exceed
100 kPa (1 mmHg, 0.04 in. Hg).
Faulty ® Replace the pressure regula-
tor.
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Increase the vacuum pressure. ®
Fuel pressure is decreased.
Decrease the vacuum pressure. ®
Fuel pressure is increased.