fuel cap NISSAN 300ZX 1984 Z31 Engine Fuel And Emission Control System Workshop Manual

PRECAUTIONS
Always use 12 volt batteries as * Do not disassemble E C C S When installing large capacity wire-
Do not attempt to disconnect Do not turn diagnosis mode sure to obsetve the following as it power source
battery cables while engine
IS
control unit
selector less equipment or a vehicle phone, be
may adversely affect electronic con-

operating
Do not apply battery power
directly to injectors
Do not remove the fuel tem-
perature sensor from
the T

pressure regulator
Replace as an assembly
trol systems depending on its installa-
tion location
1) Keep the antenna as far as possible
away from the electronic control
units
2) Also keep the antenna feeder line
more than
20 cm (7 9 in) away from
the harness of electronic controls
Do not let them run parallel for a
long distance
3) Adjust the antenna and feeder line so
that the standing-wave ratio can be
keot smaller
J
Handle air flow meter care-
fully to avoid damage * Do not disassemble auxiliary
Do not disassemble air flow air control valve (VG30ET
meter engine)
Do not clean air flow meter
with any type of detergent
0 Even a slight leak in the air in- /
&&%$$?&
take system can cause serious
problems
Do not depress accelerator Do not shock or jar the crank
angle sensor
Immediately after starting, do
pedal when starting
not rev
up engine unneces-
sarily
Do not rev up engine just prioi
to shutdown
Do not operate fuel pump when
there is no fuel in lines Do not use anti-freeze agents in fuel
0 Do not reuse fuel hose clamps
0 Tighten fuel hose clamps sufficiently
Securely connect E C C S harness
connectors
A poor connection can cause an ex-
tremely
high (surge) voltage to
develop in coil and condenser, thus
resulting in damage to IC circuit
Keep
E C C S harness at least 10 cm
(3 9 in) away from adjacent
harnesses, to prevent an
E C C S
system malfunction due to reception
of external noise, degraded operation
of
IC circuit. etc
Keep E C C S parts and harnesses
Before removing parts, turn off igni-
tion switch and then disconnect
battery ground cable dry
SEF6008
EF & EC-2

FUEL SYSTEM INSPECTION
Fuel Pressure Check (Cont'd)
6 Stop engine and disconnect fuel pressure re-
gulator vacuum hose from intake collector
7
Plug intake collector with a rubber cap
8 Connect variable vacuum source (J-23738 or
equivalent) to fuel pressure regulator.
9 Disconnect fuel pump connector and apply
battery voltage
as follows
SEF717B
10 Start engine and read the indication of fuel
pressure gauge as vacuum is changed
Vacuum Fuel prerrure
SEF718B
Vacuum Fuel pressure
kPa (mmHg, inHg) kPa (kg/cm2, psi1
0 (0.01 248 1 .255 0
(2 53
- 2 60.36 0.37 01
227 5.241 3
(2 32.2 46,330.35
01 16 9 (127, 5 00)
213 8.220 7
(2 18.2 25,31 0 - 32 01 33 9 (254. 10 001
200 1 - 206 9
(2 04
- 2 11.29 0- 30 01 50 8 (381,15 00)
179 5. 193 2
(1 83-197.260-280) 67 7 (508.20 00)
Fuel pressure should decrease as vacuum increases.
If results are unsatisfactory, replace fuel pressure
regulator.
EF 8t EC-64

EVAPORATIVE EMISSION CONTROL SYSTEM
VAPOR VENT LINE
AN
Fuel check valve
SEC306A
1 Check hoses and fuel tank filler cap
2 Disconnect the vapor vent line connecting
carbon canister to fuel tank
3 Connect a 3-way connector, a manometer and
a cock (or an equivalent 3-way charge cock) to
the end of the vent line
4 Supply fresh air into the vapor vent line
through the cock
little by little untll pressure
becomes
3923 kPa (400 mmH,O, 1575
inH,
0)
5 Shut the cock completely and leave it un-
attended
6 After 25 minutes, measure the height of the
liquid
in the manometer
7. Variation in height should remain
at 0.245 kPa
(25 mmH,
0.0 98 inHl 0)
8 When filler cap does not close completely, the
height should drop to zero in
a short time
9 If the height does not drop to zero in a short
time when filler cap is removed, the cause IS a
stuffy hose.
In case the vent line is stuffy the breathing in fuel
tank
is not thoroughly made thus causing insuffi-
cient deliver of fuel to engine or vapor lock. It
must, therefore, be repaired or replaced.
tion.
CARBON CANISTER
Check carbon canister as follows
I-
UL
@ @)
inhale air and ensure that there IS no leakage inhale air and ensure that there 81 leakage
SEC307A
If malfunctioning, replace faulty part
FUEL TANK VACUUM RELIEF VALVE
1 Wipe clean valve housing and have it in your
mouth
2. Inhale air A slight resistance accompanied by
valve indicates that valve is in good mechanical
condition Note also that, by further inhaling
air, the resistance should be disappeared with
valve clicks
3. If valve is clogged, or if no resistance is felt,
replace cap
as an assembled unit
SEC308A
EF & EC-77