1998 HONDA CIVIC fuel lines

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

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Fuel Tank Pro3sure sensor 196 D16Y8 engine (coupe).'97 D15Y7 engine {coupe: KL model, sedan: KL (LX) modeu,'97
D16Y8 engine (coupe: all models, sedan: KL model, '98-all models) '99 - 00 D16Y5 engine with M/Tl:
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PTANK
{LT GRNI
vcc2(YEL/BLU}
Wire side oI female terminals
FUEL TANKPRESSURE SENSOR3P CONNECTOR (C7921
sG2IGRN/8LK)
Foc2l::il":"toolindicatesDiagnosticTroublecode(DTc)P0452:A|owvo|tageprob|emintheFue|TankPressure
The fuel tank pressure sensor converts fuel tank absolute pressure into electrical signals and inputs the EcM/PCM.
OUTPUTVOLTAGEtvt4.5
-? kPa(-50 mmHg,-2 in.Hg)
ECM/PCM CONNECTOR O I16P)
Wire side of female terminals
+7 kPs150 mmHg,2 in.Hg)
PRESSURE
(cont'd)
11-275
- The MIL has been reported on- DTC P0452 is stored.
Check the vacuum lines:
Check the vacuum lines of the
fuel tank pressure sensor for mis-
routing, leakage, breakage and
cloggrng.
Are the vacuum lines OK?
Problem v€ritication:1. Do the ECM/PCM Reset Proce
dure.2. Remove the luel fill caP.
3. Turn the ignition switch ON lll)4. Monitor the FTP Sensor volt_
age with the Honda PGM
Tester, or measure voltage
between bodY ground and
ECM/PCM terminal Dl5.lntermittent tailuro, sYstem i5 OK
dt this timo. Chock for Poot con-
neciion3 or loose wir* at C131
llocatod under right side ot dashl,
C4O1 (located .bove under'da3htuso/ielay box), C574 1C568)*
{located under acc€ss Panell.C792 lfuel tank pressule sen3or)
and EcM/PCM.
ls there approx. 2.5 V?
Check tol an op€n in wite (VCC2
line):1. Turn the ignition switch OFF
2. Reinstallthe fuel fill caP.3. Disconnect the fuel tank Pres'sure sensor 3P connector-4. Turn the ignition switch ON (ll)
5, Measure voltage between the
fuel tank pressure sensor 3P
connector No. l terminal and
No. 2 terminal.
Repair open in the wite betweenthe fuel tank Pr€s3ure a€n3or andth6 EcM/PcM (D1ol.ls there approx. 5 V?
(To page 11'276)

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'99 - 00 models excepi Dl6Y5 engine with M/T:
The scan tool indicates Diagnostic Trouble Code (DTC) P0452: A low voltage problem in the Fuel Tank Pressure
sensor.
The fuel tank pressure sensor converts fuel tank absolute pressure into electrical signals and inputs the ECM/PCM
OUTPUTVOLTAGE(vlt.5
0.5-7 kP.(-g) mmHg,-2 in.Hgl
+7 kP.
150 mmHg,2 in.Hgl
PRESSURE
I
Wire side of lemale terminals
FUEL TANKPRESSURE SENSORSUB.HARNESS6P CONNECTOR (C574 (C568)rl
vcc2(YEL/BLUIsG2{GRN/BLK}
Wire side o{ temale terminals
The MIL has been .eported on.
DTC P0452 is stored
Check the vacuum lines:
Check the vacuum lines of the
fuel tank pressure sensor lor mis-
routing, leakage, breakage and
cloggrng.
Are the vacuum hnes OK?
Problem veritication:1. Do the ECM/PCM Reset Proce-
du re,2. Bemove the fuel fill caP.
3. Turn the ignition switch ON {ll)
4. Monitorthe FTP Sensor voltage
with the Honda PGM Tester' or
measure voltage between body
groLrnd and ECM/PCM connec_
tor terminalA29.
lntermitlent tailure, 3Ystem b OK
at this time. Check for Poor con'
nections or loose wire3 at C131
{located under right side of dash},
C401 {located above under'dash
tuse/relay box), C574 (C568)*
llocdted under access Panel),C792 (tuel rank Prcssure sensorl
and ECM/PCM.
ls there approx.2 5 V?
Check for an open in wire {VCC2
line):1. Turn the ignition switch OFF.
2. Reinstall the ltrel fill caP
3, Remove the access Panel from
the floor.4. Disconnect the fuel tank Pres'sure sensor sub-harness 6P
5. Turn the ignition switch ON (ll).
6. At the access Panel side, mea_
sure voltage between the fuel
tank Pressure sensor sub-nar-
ness 6P connector No 5termi
nal and No. 6 termlnal.
Repair open in tho wire between
th6 fu€l tank Prossuro sen3oa and
the ECM/PCM lc28).ls there approx 5 V?
ECM/PCM CONNECTOR A (32P)
PTANK {LT BLUI
I
ll
(To page '11-278)
(cont'd)

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Fue| Tank Pr€ssure sensor 196 Dr6Y8 engine (coupe},,97 D16Y7 angino (coupo: KL mode|' 3edan: KL (Lxl modg||',97
Dl6Y8 engine (coupe: all modeb, sedan: Ki model.'98'all modols) 39 - 0O Dl6Y5 ongins with M/Tl:
rFoG'l::;Jl"too|indicatesDiagnosticTroub|ecode(oTc)P0453;Ahighvo|tageprob|emintheFue|TankPressure
ECM/PCM CONNECTOR D Il6PI
PTANKILT GRNI
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Wire side of tgmale torminals
FUEL TANKPRESSURE SENSOR3P CONNECTOR (C792)
vcc2(YEL/BLU}
sG2(GRN/BLKI
Wire sid€ of female terminals
I
sG2IGRN/BLKI
PTANKIGBN/RED}
(cont'd)
11-279
The MIL has beon reponed on
DTC P0453 b stored.
Check the vacuum lines:
Check the vacuum lines oI the
fueltank pressure sensor for mis-
routing, leakage, breakage and
clogging.
Are the vacuum lines OK?
Problem verification:1. Do the ECM/PCM Reset Proce-
dure.2. Femove the fuel fill cap
3. Turn the ignition switch oN (ll).
4. Monitor the FTP Sensor volt-
age with the Honda PGM
Tester, or measure voltage
between bodY ground and
ECM/PCM connector termrnal
D15.
lntormittont t iluro, 3Ystem is OK
at this time. Check lot Poor con_
noctiona or loo3e wirat at C131
{loc.ted undor right 3id6 of d8hl,
CaOl llocatod rbov. under-dalh
fus6/relay boxl, C574 (C568lr
llocatod und6l accoss Pan6ll,C792 lfuel tank Preasulo aonlorl
end ECM/PCM.
ls there approx. 2 5 V?
Check for an oPen in the wire(SG2line):1. Turn the ignition switch OFF.
2. Reinstall the fuellill cap
3. Disconnect the fuel tank Pres-sure sensor 3P connector.
4. Turn the ignition switch ON (ll)
5. Measure voltage between the
fuel tank Pressure sensor 3P
connector terminals No. 1 and
No.2.
Ropair opon in the wira b€tw€sn
the fuel tank prasure sonlor and
ECM/PCM (Dl1).ls there aPProx. 5 V?
Check for an open in the wire(PTANK line):Measure voltage between the
fueltank Pressure sensor 3P con-
nector No. 3 terminal and No. 2
termrnal,
ls there approx. 5 V?
*: coupe
{To page 11-280)

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'99 - 0O modols except Dl5Y5 engine with M/T:
rFo45'::n":"tooIindicatesDiagnosticTroub|ecode(DTc)P0453:Ahighvo|tageprob|emintheFUelTankPressure
Wire side of temale terminals
FUEL TANKPRESSUNE SENSOR
SUB.HARNESS6P CONNECTOR {C574 (C568)}}
vcc2{YEL/BLUI
sG2IGRN/BLK)
Wire side of female terminals
PTANK{LT GRNI
(cont'd)
11-281
ECM/PCM CONNECTOR A {32P)
PTANK {LT GRN)
The MIL has been reported on.
DTC P0453 is stored.
Check the vacuum lines:
Check the vacuum lines ot the
fuel tank pressure sensor for mis-
routing, leakage, breakage and
clogging.
Are the vacuum lines OK?
Problem verilication:1. Do the ECM/PCM Reset Proce-
du re,2. Remove the fuel fill caP
3. Turn the ignition switch ON (ll).
4. Monitor the FTP Sensor volt'
age with the Honda PGM
Tester, or measure voltage
between body ground and
ECM/PCM connector terminalA.29.
lntermittent failuro. svstem b OK
at this time. Check for Poor con_
noctions or loo3€ wire3 at C131
{located under tight side of dash),
C4Ol {located above underdash
fuse/relay boxl, C57{ (C5681'
llocaled unde. access Panell,C792 {fuel tank Pressure sensorl
aod ECM/PCM.
ls there approx.2.5 V?
Ch€ck for an open in the wira
{SG2line):1. Turn the ignition switch OFF.
2. Reinstall the fuel fill caP
3. Remove the access Panellrom the floor.
4. Disconnect the fuel tank Pres-sure sensor sub-harness 6P
5. Turn the ignition switch ON (ll)
6, At the access Panelside, mea-
sure voltage between the fuel
tank pressure sensor sub_har-
ness 6P connector termlnals
No.5 and No.6.
Repair open in the wire between
the fueliank Pres3ure 3ensor and
ECM/PCM {Cl8).ls there approx.5 V?
Check lor an oPen in the wire
{PTANK linel:At the access Panel side, mea
sure voltage between the fuel
tank pressure sensor suo_harness
6P connector No. 2 terminal and
No. 6 terminal.
ls there approx. 5 V?
(To page 11.282)

Heater Unit
Replacement
SRS components are located in this area. Review the
SRS component locations, precautions, and procedures
in the SRS section {24} before performing repairs or ser-
L Disconnect the negative cable from the battery.
2. Frcm under the hood, open the clamp, then discon-
nect the heater valve cable from the heater valve
arm. Turn the heater valve arm to the fully opened
position as shown.
When the engine is cool. drain the engine coolant
from the radiator (see section 10).
!@ Do not remove the radiator cap when
the engine is hot; the ongine coolant is under pres'
surg and could severely scald you.
CLAMP
HEATER VALVC CABLE
4. Disconnect the heater hoses from the heater unit.
CAUTION: Engine coolant will damage p8int.
Ouickly rinse any spilled engins coolant from painted
su aces,
NOTE: Engine coolant will run out when the hoses
are disconnected; drain it into a clean drip pan.
5. Remove the mounting nut from the heater unit.
NOTE: When removing the mounting nut, take care
not to damage or bend the fuel lines, the brake
lines, etc.
I x 1 .25 mm22 N.m {2.2 kgl.m, 16lblftl
21-39