fuel pressure HONDA CIVIC 1996 6.G Service Manual

PGM-FI System
Fuel Supply System
D017-il Th""""ntool indicates Diagnostic Troubte Code {DTC) p0171;Thefuet system istoo lean.
1P0172 | fne scan tool indicates Dlagnostic Trouble Code (DTC) P0172:Thefuel system istoo rich.
Description
By monitoring the Long Term Fuel Trim, long term malfunctions in the fuel system will be detected.lf a malfunction has been detected during two consecutive trips, the MIL will come on and DTC P0171 and/or P0172 will bestored.
NOTE: lf some of the DTCS listed below are stored at the same time as DTC P0171 andlot P0172, ltouhleshoot those DTCSfirst. then recheck for DTC P0l7l andlot P0172.
P0106-8, P1128*3. *5, P1129*3 *5 MAP Sensor
P0135; Primary HO2S Heater
P0137. P0138: Secondary HO2S
P0'141: Secondary HO2S Heater
P0401: EGR Flow Insufficient*1
P0441: EVAP System Insufficient Purge Flow*6
P1259: VTEC System*,
P1491:EGR Valve Lift Insufficient*r
P1498: EGR Valve Lift Sensor Hjgh Voltage*r
*r: D16Y5 engines*': Dl6Y5, D16Y8, 81642 engine*3: '97 models*a:'96 modelsf 5: '98 - 00 models*6: '96 D16Y5 engine,'96 D16Y7 engine,'96 D16Y8 engine (sedan),'97 D16y5 engine,,97 D16y7 engine (coupe: KA, KC mo+els, sedan KA. KC, KL (DX) models. hatchback; all models),'97 D16Y8 engine (sedan: KA, KC models)
Possible Cause
DTC P0'171
loo lean
DTC P0172
too rach
Fuel Pump insuff icient f lovpressure
Fuel Feed Line clogged, leaking
Fuel Pressure Regulator stuck open
Fuel Filter clogged
Fuel Injector clogged, air inclusion
Gasoline doesn't meet Owner's Manual spec.
Primary HO2S (Sensor 1) deteriorated
MAP Sensor range/performance*.
EGR System malfunction (too much flow)*1
Valve Clearance
Exhaust leak
Fuel Pressure Regulator clogged, stuck closed
Fuel Return Pipe clogged
Fuel Injector leaking
Gasoline doesn't meet Owner's Manual spec.Primary HO2S (Sensor 1) deteriorated
MAP Sensor range/performance*a
EGR System insufficient flow*1
EVAP Purge Control Solenoid Valve leaking, stuck opened
Valve Clearance
11-164

t
Troubleshooting Flowchart
'l
NO
a-,-:- -
YES
- The MIL ha3 b€on rePorled on.- DTC P0171 a^dlot P0172 arc
stored,
is the fuel pressure OK?
Check the fuel pt€ssure regulator
and fusl re{urn pipe.ls the fuel pressure too high
ortoo low?
Check the Primary HO2S:
1. Start the engine. Hold the
engine at 3,000 rpm with no
Ioad (in Park or neutral) until
the radiator Ian comes on
2. Check the Primary HO2S(Sensor 1) output with the
scan tool,
Check the tu6l pump. fuel leedpipe, fu€l fiher, and Iuel Pressureregulator.
Does it stay at less than 0.3 V
or more than 0.6 V?
Check lor a sticking or leaking
EVAP purge control solenoid
With a vacuum PumP, aPPIY vacu-
um to the EVAP purge control
solenoid valve from the intake
manifold side.
Does it hold vacuum?
Check the MAP sensor outputr
1. Turn the ignition switch ON (ll)
2. Check the MAP with the scan
tool.
Check th6 response of the MAP
sensoa:1. Start the engine.2. Check the MAP with the scan
tool.
ls a MAP of 40.0 kPa 1300 mmHg,12.0 inHg) or less indicated within
one second after starting the
engine?
- Check th€ valve cloarance.- Check the EGR rystem lD16Y5enginel.- lf they are OK, r€place the tueliniocto]3.
1 1-165

PGM-FI System
Random Misfire
lFoioo l*u o, [FTioo l*' *' and
The scan tool indicates Diagnostic Trouble Code (DTC)
P0300*5 or P1300*3 *1 and some of P0301 - P0304:Random misfire.Description
Misfire detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluctuation (CKF) sensorwhich is attached to the crankshaft.
lf misfiring strong enough to damage the catalyst is detected. the MIL will blink during the time of its occurrence, and DTCP0300*5 or P1300*3'*' and some of DTCs P0301 through P0304 will be stored. Then, after misfire has ceased, the MIL willcome on.
lf misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTCP0300*5 or P1300*3 *a and some of DTCS P0301 through P0304 will be stored.NOTE: lf some of the DTCS listed below are stored at the same time as a misfire DTC. troubleshoot those DTCS first, thenrecheck for the misfire DTC.
P0106*4. P0107. P0108, P1128*3 *5, Pl129*3 *5; MAP sensorP0131. P0132: HO2S
P0171, P0112i Fuel metering
P0401, P 1491, P1498: EGR svstem*1P0505: ldle Control SystemP1253: VTEC System*,P1361, P1362: TDC sensorP1381, Pl382: CYP sensorP1508: IAC valve
Possible Cause. Fuel pump insufficient fuel pressure, amount of flow. Fuel line clogging, blockage, leakage. Fuel filter clogging. Fuel pressure regulator stuck open. EGR system malfunction*1. Distributormalfunction. lgnition coil wire open. leakage *l: D16Y5 engine. lgnition control module malfunction *2: D16Y5, D16Y8, Bt6A2 engine. MAP sensor range/performance, poor response*r *3: '97 models. Valves carbon deposit *4;'96 models. Compression low *5: '98 - 00 models. IAC valve malfunctionr.. VTEC system malfunction*,. Fuel does not meet Owner's Manual spec., lackoffuel. HO2S. HO2S circuit
Troubleshooting
By test-driving, determine the conditions during which misfire occurs, Depending on these conditions, test in the orderdescribed in the table below.
Possible
- --^ ---
rage
causeEGR*1
system
Crankshaft
position (CKP)
sensor
Fuel
pressure
Distributor and
lgnition wirestcMClearance
tAc
ValveMAP
sensor
section 611-230,
231section 23section 23section 611-19411
Only low rpm and
loado@@oo
Only accelerating@o@@
Only high rpm and
toaooo@
Not specificoo@
NOTE: lf misfire doesn't recur, some possible causes are fuel that doesn't meet owne/s manualspec, lack of fuel, carbon deposits on spark plug, etc.
1 1-1 66
I
P0304

I'96 - 98 models:
NOTE: Check all hose clamps and retighten if necessarY.
M
/vFUELFILTER
PRESSUREREGULATOR
IFUELTANKFUELGAUGESENDINGUNITBASE GASKETReplace.
Clamp In rhe middle
@
Clamp in the middle
10-14mm(0.39 - 0.55 inl
(cont'd)
11-225

Fuel Supply System
Fuel Lines (cont'dl
.99 - 00 models:
NOTE: Check all hose clamps and retighten if necessary.
: Do not disconnect the hose from the pipe.
ONBOARD REFUELING VAPORBECOVERY IORVRIVENT SHUT VALVE
B
FUELGAUGElt N.rn l1.a kgt.m,r0 lbt ftl
ftr, n'fo'PRESSUREREGULATOR
Clamp in the middle
Clamp in the middle
11-226

I
Fuel Tube/Ouick-Gonnect Fittings
Precautions
!@ Do not smoke while working on the fuel
system, Keep open flames away from your work a.ea'
The fuel tube/quick-connect fittings assembly connects
the in tank fuel pump with the fuel feed pipe. For remov-
ing or installing the fuel pump and fuel tank, it is neces-
sary to disconnect or connect the quick-connect fittings.
Pay attention to lollowing:
. The fuel tube/quick-connect fittings assembly is not
heat-resistant; be careful not to damage it during
welding or other heat-generating procedures
. The fuel tube/quick-connect fittings assembly is not
acid-proof; do not touch it with a shop towel which
was used for wiping battery electrolyte. Replace the
fuel tube/quick-connect fitlings assembly if it came
into contact with electrolyte or something similar.
. When connecting or disconnecting the fuel tube/
quick connect liltings assembly, be careful not to
bend or twist it excessively. Replace it if damaged
A disconnected quick-connect fitting can be reconnecled,
but the retainer on the mating pipe cannot be reused
once it has been removed from the pipe. Replace the
retatner wnen
. Replacing the fuel pump.
. Replacing the fuel leed pipe.
. lt has been removed lrom the PiPe.. lt is damaged.
ACCESS PANEL
I
Disconnestion
!@ Do not smoke while working on the luel
system. Keep open llames away lrom youl work area.
1. Relieve fuel pressure (see pages 11'230,2311.
2. Check the tuel quick-connect tittings for dirt, and
clean if necessary.
3. Hold the connector with one hand and press down
the retainer tabs with the other hand, then pull the
connector off.
NOTE:
o Be carelul not to damage the pipe or other pans
Do not use tools.
. lf the connector does not move, keep the retainer
tabs pressed down, and alternately pull and push
the connector until it comes off easily.
. Do not remove the retainer from the pape; once
removed, the retainer must be replaced with a
new one.
LOCKING PAWL
BETAINER TAB
CONNECTOR
Check the contact area o{ the pipe for dirt and dam-
age.
. lf the surface ls dirty, clean it.
. lf the surface is rusty or damaged, replace the
fuel pump or fuel feed piPe.
4.
(cont'd)
11-227
PIPE

t
Belore connecting a new fuel tube/quick-connect fining
assembly, remove the old retainer from the mating pipe
with thetabs pulled
apan, removeand discard the
I
retarner
New FUEL TUBE/OUICK.CONNECTFITTING ASSEMELY
3. Align the quick-connect fiftings with the pipe, and
align the retainer locking pawls with the connector
grooves. Then press the quick-connect fittings onto
the pipe until both retainer pawls lock with a click-
ing sound.
NOTE: lf it is hard to connect, put a small amount
of new engine oil on the pipe end.
Connection with new retainer:
4. Make sure the connection is secure and the pawls
are firmly locked into place; check visually and by
pulling the connector.
RCTAINER
Reconnect the battery negative cable, and turn the
ignition switch ON (ll). The fuel pump will run for
about two seconds, and fuel pressure will rise.
Repeat two or three times, and check that there is
no leakage in the fuel supplv system
11-229

Fuel Supply System
System Description
The fuel supply system consists of a fuel tank, in-tank
high pressure fuel pump, PGM-FI main relay, fuelfilter,
fuel pressure regulator, fuel injectors. and fuel delivery
and return lines. This system delivers pressure-regu-
lated fuel to the fuel injectors and cuts the fuel delivery
when the engine is not running.
Fuel Pressure l'96 Modelsl
Relieving
Before disconnecting fuel pipes or hoses, release pres-
sure from the system by loosening the 6 mm service
bolt on top of the fuel filter.
. Do not smoke whil6 working on the fuel system.
Kgsp opon flames or sparks away from youl work
area.
. Be sure to relieve fuel pressure while the ignition
switch is off.
1. Write down the frequencies for the radio's preset
buttons.
2. Disconnect the battery negative cable from the bat-
tery negative terminal.
3. Remove the fuelfill cap,
4. Use a box end wrench on the 6 mm service bolt at
the fuel filter while holding the special banjo bolt
with another wrench,
5. Place a rag or shop towel over the 6 mm service bolt.
6, Slowly loosen the 6 mm service bolt one complete
rurn.
. A fuel pressure gauge can be attached at the 6 mm
service bolt hole.
. Always reDlace the washer between the service
bolt and the special banjo bolt whenever the ser-
vice bolt is loosened.
. Replace all washers whenever the bolts are
removeo.
11-230
Inspoction
1. Relieve fuel pressure.
2. Remove the service bolt on the fuel filter while hold-
ing the banjo bolt with another wrench. Attach the
special tool.
FUELPRESSUREGAUGE07406 - 00ir0(x)1
Start the engine. Measure the fuel pressure with the
engine idling and the vacuum hose of the fuel pres-
sure regulator disconnected from the fuel pressure
regulator and pinched. lf the engine will not start,
turn the ignition switch ON (ll), wait for two sec-
onds, turn it off, then back on again and read the
fuel pressure.
Pr€3sure should bo:
260 - 310 kPa (2.7 - 3.2 kgt/cmr, 38 - 46 psi)
Reconnect vacuum hose to the fuel pressure regulator,
Pressure should bo:
200 - 25O kPa l2.O - 2.5 kgf/cm', 28 - 36 psil
lf the fuel pressure is not as specified, first check the
fuel pump {see page 11-2361. lf the fuel pump is OK,
check the following:
. lf the fuel pressure is higher than specified,
inspect for;- Pinched or clogged fuel return hose or line.- Faulty fuel pressure regulator (see page 11-234).. lf the fuel pressure is lower than specified, inspect
for:- Clogged fuelfilter.- Faulty fuel pressure regulator {see page 11-234).- Fuel line leakage.
REGULATOB

tJFuel Pressure {'97 and later Models)
ReliGving
Before disconnecting tuel pipes or hoses, release pres-
sure from the system by loosening the 12 mm banjo
bolt on top of the fuel filter.
@o Do not smoke whilo working on the fuel sy3lom.
Ksgp op€n flames or sparks away tlom Your work
arga.
. Be sure to relieve fuel pressule while the ignition
swhch is off.
1. Write down the frequencies for the radio's preset
buttons,
2. Disconnect the battery negative cable from the bat-
tery negative terminal.
3. Remove the fuel fill cap.
Use a box end wrench on the 12 mm banjo bolt at
the fuel filter while holding the fuel filter with anoth-
er wrench.
Place a rag or shop towel over the 12 mm banio bolt.
Slowly loosen the 12 mm banjo bolt one complete
turn.
4.
I
12 mm BAtt OBOLT33 N.m (3.i1 kgf m,25 tbf.f0
NOTE: Replace all the washers whenever the 12
mm banio bolt is loosened or removed.
Inspaqtion
1. Relieve fuel pressure.
2. Remove the 12 mm banjo bolt from the fuel filter
while holding the fuel Jilter with another wrench
Attach the special tools.
3. Start the enginethe fuel Pressure with the
engine idling and the vacuum hose of the fuel pres-
sure regulator disconnected from the fuel pressure
regulator and pinched lfthe engine will not start, turn
the ignition switch ON {ll), wait for two seconds, turn
it off, then back on again and read the fuel pressure'
Pr$3uro ehould be:
excepi 816A2 sngine:
260 - 310 kPa {2'7 - 3.2 kgf/cm" 38 - {6 Fi}
B16A2 engine:
27O -32O kPa P.8 - 3'3 kgf/cm', '10 - 47 psi)
4. Reconnect vacuum hoso to the fuel pressure regulator'
Pre33ure 3hould be:
except B16A2 engin€:
2OO - 250 kPa {2.0 - 2'5 kgf/cm', 28 - 36 psi)
B16A2 engino:
210 - 260 kPa 121 - 2.6 ksf/cm', 30 - 37 psi)
lf the fuel pressure is not as specified, first check the
fuel pump (see page 11-236) lfthetuel pumpisoK,
check tho following:
. lf the fuel pressure is higher than specified,
inspect for:- Pinched or clogged fuel return hose or line.
- Faulty fuel pressure regulator (see page 11-
2341.
. lf the fuel pressure is lower than specified, inspect
for:- Clogged fuel filter.
- Faulty fuel pressure regulator (see page l1-
2341.- Fuel line leakage.
FUEL PRESSUREADAPTER BOLT, 12 mm
tguxt8-PD6-0101
CLAMP
REGULATOR
11-231

Fuel Supply System
Fuel Injectors
Replacement
@ Do not smoke when working on the tuel systgm, Keep gp6n flames away from your work area
'f. Relieve the fuel pressure (see pages 11-230,231J.
2. Disconnect the connectors from thefuel injectors (D16Y7 engine: Remove the air cleaner).
3. Disconnect the vacuum hoses from thefuel pressure regulator. Placeashoptowel overthefuel return hose, then dis-connect it from the fuel pressure regulator. Disconnect the vacuum hoses and 2P connector from the EVAp purgecontrol solenoid valve.
4. Remove the retainer nuts on the fuel rail.
5. Disconnect the fuel rail.
6. Removethefuel injectors from the intake manifold.
D16Y5, D16Y8 engine:
NOTE: lllustration shows D16Y8 engine.
D16Y5 engine is similar.
12 N.m11.2 kgl.m,8.7 rbt.ft)
12 N.m11.2 lgl.m,8.7 rbt.ftl
.q
wE4
Y
Ve
ffi}Yg
E
O.RINGReplace.
CUSHIONRINGReplace.
O.RINGReplace.
cusl{toNRINGReplace.
SEALRINGReplace.
ffi
E
EV
R
w
t
YEVAPPURGE CONTNOLSOLENOID VALVE
FUEL
11-232