1998 HONDA CIVIC din

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

lntake Air System
Air Cleaner (ACLI
NOTE: Do not clean the ACL element it with com-pressed air {except dry type).
D16Y5, D16Y8, 816A2 engine:
ACL ELEMENTNormal conditions:Replace air cleaner element every30,000 miles (48,000 km) or 24months whichever comes first.S€voae conditions:(Use normal scheduleexcept in dusty conditions)Replace every 15,OOOmiles (24,000 km)or 12 monthswhichever comes first.
D16Y7 engine:
ACL ELEMENTNormal conditions:Replace air cleaner element every30,000 miles (48,000 km) or 24months whichever comes first,Seve.s conditions:(Use normal schedule exceptin dusty conditions)Replace every l5,000
whichever comes first.
11-244
Throttle Cable
Inspection/Adiustment
1. Start the engine. Hold the engine at 3,000 rpm withno load (in Park or neutral) until the radiator fancomes on, then let it idle.
2. Check that the throftle cable operates smoothly withno binding or sticking. Repair as necessary.
3. Check cable free play at the throttle linkage. Cabledeflection shoutd be 10- l2 mm (3/B - 112 in.l.
D16Y5, D16Y8 engine:
CABLEBRACKETLOCKNUT
DEFLECTION10-12mm
BIA- 112 inl
D16Y7 engine:
LOCKNUT
DEFLECTION10- 12 mml3lA - lninl

IThrottle BodY
Description
The throttle bodY is either a single-barrel side-draft type
(D16Y5, D16Y8, 816A2 engine) or a down-draft type
(D16Y/ engine). The lower portion ot the throttle valve is
heated by engine coolant from the cylinder head' The
idle adjusting screw which regulates the bypass air is
located on the top of the throttle body
THROTTLEPOS|T|ON lTPlSENSOR
IDLE AD.'USTINGSCREW
t
In3pection
1. Check that the throttle cable operates smoothly
without binding or sticking.
lf there are any abnormalities, check for:
. Excessive wear or play in the throttle valve shaft'
. StickY or binding throttle lever at the fully closed
Position.. Clearance between throttle stop screw and throt-
tle lever at the fully closed position'
D16Y5, Dl6Y8 engine:
THROTTLE STOP SCREW
{Do not adjust.)
Dl6Y7 ongine:
816A2 engins:
THROTTLE LINK
STOP SCREW
THROTTTE STOP SCREW(Do not adjust.)
Replace the throftle body if thsre is excessive play in the
throttle valve shaft or iJ the shaft is binding or sticking'
(cont'd)
11-247
{Do not adjust.)

\J
Fuol Iniection Air {FlA) Contlol Valve T$ting
1. Start the engine.
2. Remove the vacuum hose from the fitting on the
intake air duct, and connect a vacuum gauge to the
nose.
NOTE: Engine coolant temperature must be below
149"F (65"C).
VACUUM PUMP/GAUGE,
0-30 in.Hg.A973X - 041 -XXXXX
Raise and lower the engine speed, and make sure
the vacuum gauge reading changes as the engine
speed changes.
lf vacuum reading does not change check these
rtems:
. The vacuum lines of FIA system for misrouting,
leakage, breakage and clogging.
. The FIA controt valve for cracks or damage
. The cooling system (see section 10).
Hold the engine at 3,OOO rpm with no load (in Park
or neutral) until the radiator fan comes on, th€n let
it idle and recheck.
lf vacuum reading changes check these items:
a The FIA control valve for cracks or damage.
. The cooling system (see section 10).
11-251

Emission Gontrol System
System Description
The emission control system includes a Three Way Cata-lytic Convener (TWC), Exhaust Gas Recirculation (EGR)
system,. Positive Crankcase Ventilation (pCV) system andEvaporative Emission (EVAP) Control system. The emis-sion control system is designed to meet federal and stateemission standards.*: D16Y5 engine
Tailpipe Emission
Inspestion
@@ Do not smoke during ihis procedure. Keepany open flame away from your work area.
1. Start the engine. Hold the engine at 3,000 rpm withno load (in Park or neutral) until the radiator fancomes on. then let it idle.
2. Connect a tachometer.
Check and, if necessary, adjust the idle speed (see
page 11-220 - 223).
Warm up and calibrate the CO meter according to themeter manufacturer's instructions.
Check idle CO with the headlights, heater blower,rear window defogger, cooling fan, and air condition-er off.
NOTE: (Canada) Pull the parking brake lever up.Start the engine, then check that the headlights areoff.
CO mete. should indicate 0.1% maximum.
NOTE: '98 Dl6Y5 engine - lf the idle speed incress-es to 8101 50 rpm, this means the EVAp system ispurging the canister. To stop the purging temporari-ly. raise the engine speed above 1,000 rpm with theaccelerator pedal, then slowly release the pedal.
11-252
eFORWARD -
Three Way Catalytic Converter
(TWCI
Doscription
The Three Way Catalytic Converter (TWC) is used toconven hydrocarbons (HC), carbon monoxide (CO), andoxides of nitrogen (NOx) in the exhaust gas to carbondioxide (COr), dinitrogen (N,) and water vapor.
D15Y5, D16
, engine:
'99 - 00 D16Y8, 81642 engine:
ENGINE SIDE
t

\
lTo420l Th" """n toot indicates Diagnostic Troubte code (DTc) p0420: catatyst sysrem efficiency below threshold.
Description
This system evaluates the catalyst's capacity by means of the Ho2s {Primary and secondary) output during stable driving
conditions. ll deterioration has been detected during two consecutive driving cycles. the MIL comes on and DTC P0420 will
be stored.
NOTE: lf some of the DTCS tisted below are stored at the same time as DTC P0420, troubleshoot those DTCS first. then
recheck for DTC P0420
P0137, P0138: Secondary HO2S (Sensor 2)
Po14'1:Secondary H02S {Sensor 2) Heater
Possibl€ Cause
. TWC Deterioration
. Exhaust system leakage
Troubleshooting Flowchart
I
The MIL has been reported on.
DTC P0420 is stored
Problem verilication:1. Do the ECM/PCM Reset Proce
dure.2. Start the engine Hold the
engine at 3,000 rpm wath no
load {in Park or neutral) until
the radiator fan comes on.
3. Connect the SCS service con
4. Test drive 40 - 55 mph for
approx, two minutes Then
decelerate for at least 3 sec_
onds with the throttle com'pletely closed- Then reduce
the vehicle speed to 35 mph,
and try to hold it until the
readiness code comes on
Intermittent Iailure, system is OK
at this time.ls DTC P0420 indicated?
Check the TWC {see section 9l
lf necessary, replace the TwC

Emission Control System
Evaporative Emission (EVAP) Gontrols (cont'd)
'99 - 0O models only:
The scan tool indicates Diagnostic Trouble Code (DTC) P0451: The Fuel Tank Pressure sensor circuit range/oerformance Droblem.
ECM/PCM CONNECTORS
wire side ot femare terminars sG2 IGRN/BLK)
FUEL TANKPRESSURESENSOR
VACUUMPUMP/GAUGE,0 - 30 in.Hg
FUEL TANKPRESSURE SENSORASSEMBLY
EVAP TWOWAY VALVE
IJ
tl'
Ths MIL has been reDortgd on.DTC m/$1 i3 stored.
Check the tuel tank pros3ure ser|-sor:1. Do the ECM/PCM Reset Proce-dure.2. Remove the tuellill cap.3. Turn the ignition switch ON (ll).4. N4onitor the FTP Sensor volt-age with the Honda PGMTester, or measure voltagebetween body ground andECN4/PCM connector terminalsA29 and C18.
ls there approx. 2.5 V7
Check tho tuel tank pressure !on-soa:1. Remove the fuel tank (seepage 11 2421.2. Remove the fuel tank pres-sure sensor assembly fromthe fueltank.3. Connect the fuel tank PressureSensor sub-harness 6P con-nector to the access panelside connector,4. Disconnect the hose betweenthe EVAP two way valvg andthe fuel tank pressure sensor atthe EVAP two way valve end.5. Connect a vacuum pump tothe open end ofthat hose.6. Turn the ignition switch ON (ll).7. Monitor the FTP Sensor volt,age with the Honda PGMTester, or measure voltagebetween ECM/PCM connectorterminals A29 and C18, andcarefully pump vacuum on thehose one stroke at a time.8. The voltage sho!ld smoothlydrop from the stading approx.2.5 V down to approx. '1.5 V.STOP applying vacuum whenthe voltage drops to approx. 1.5V or damage to the fuel tankpressure sensor may occur.
Does the voltage drop toapprox. 1.5 V and hold?
Sub3titute a known-good ECM/PCM and r6check. It symptom/indicltion 90e3 aw.y, replac\. th€original ECM/PCM.
A (32P)
A973X - 041 -
xxxxx
11-274