valve stem HONDA CIVIC 1998 6.G Repair Manual

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
Misfire Detected in One Cylinder
P0301 | The scan tool indicates Diagnostic Trouble Code (DTC) P0301: Cylinder 1 misfire detected.
[F03O2l 16"""untool indicates Diagnostic Trouble code (DTc) P0302: Cylinder2 misfire detected.
[FO3Ofl 16" ".un toot indicates Diagnostic Troubte Code (DTC) P0303; Cylinder 3 misfire detected.
I P0304 I ths..rr tool indicates Diagnostic Trouble Code (DTC) PO3O4: Cylinder 4 misfire detected.
D€scription
lMisfire detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluctuation (CKF) sensor
which 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 DTC
PO3O1, P0302, PO3O3 or P0304 will be stored. Then, after the misfire has ceased, the MIL will come on.
lf misfiring that increases emissions is detected during two consecutive driving cyclss, the MIL will come on, and DTC
P0301, P0302, P0303 or 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, then
recheck for the misfire DTC.
PO106*1, P0107, P0108. P1128*3'*5, P1129*3'*5: MAP sensor
P0131, P0132: HO2S
P0171, P0172iFuel suppiy system
P0335, P0336: CKF sensor
P0401. P1491, P1498: EGR system
P0441: EVAP system Insufficient purge flow*6
Pl359. P1361. Pl362: TDC sensor
P1381. Pl382: CYP sensor*o: '96 models*6: '96 D16Y5 engine,'96 D16Y/ engine,'96 D16Y8 engine {sedan),'97 D16Y5 engine,'97 D16\4, engine (coupe: KA,
KC models, sedan KA. KC, KL (DX) models, hatchback:all models),'97 D16Y8 engine (sedan: KA, KC models)
Possible Cause
. Fuel injector clogging, fuel leakage, air leakage
. Fuel injector circuit open or shorted
. Spark plug carbon deposits, fouling, malfunction
. lgnition wires open. leaking
. Distributor malfunction
. ComDression low
. Valve clearance out of spec
. VTEC system malfunction (D16Y5, D16Y8. 81642 engine)
. HO2S
. HO2S circuit
(cont'd)
11-167
r'a

ldle Control System
System Description
The idle speed ot the engine is controlled by the ldle Air Control (lAC) Valve.The valve changes the amount of air bypassing into the intake manifold in response to electric current controlled bv theECM/PCM. When the IAC Valve is activated, the valve opens lo maintain the proper idle speed.
D16Y5, D16Y8, Br6A2 engine (M/T):
(ROTARYItac vat-vEEI{GINEcooLAI{T
VARIOUSsEI{SORS
VARIOUSSENSORS
INTAKE MANIFOTDDl6Ys {CVTl, D16Y8 engine lA/T):
D16Y7 engine:
{ROTABY)
;iy--, - --- INTAKEMANIFOLD
11-190

ldle Control System
ldle ControlSystem
lF0505 l Th" """n tool indicates Diagnostic Trouble Code (DTC) PO5O5: tdte controt system malfunction.
NOTE: lf DTC P1508 or P1509 is stored at the same time as DTC P0505, troubleshoot DTC p1508 or p1bog first. thenrecheck for DTC P0505.
Possible Cause
. IAC valve mechanical malfunction
. Throttle body clogged pon, improper adjustment. Intake manifold gasket leakage
. Intake air hose loose leakage
. Vacu um leak
. ECT sensor incorrect output
. Throttle Position sensor incorrect output*r
Troubleshooting Flowchart
The MIL has been reoorted on.DTC P0505 is stored.
Problem verification:1. Start the engine. Hold theeng;ne at 3,000 rpm with noload (jn Park or neutral) untilthe radiator fan comes on, then*r let it idle.t2. with rhe scan toot, ct'eit Ge l
Throttle position should beapprox. 10% with the throttle fully closed.E ngine coolant tempera-ture should be 194 205'F(90 96.Ci.lf they are not within thespec., repair the faulty sen
L._ _9oI9[cr]41 l3. Chec& the engine speed atidle with no-load cond;tionsiheadlights, blower fan, reardefogger, radiator fan, and airconditioner are not operating\see page l1-22O - 223).
Intermittent tailure, system is OKat this time.ls the idle speed OK?
ls it 550 rpm or less?
(To page 11,193)
*1r'96 models only
11-192
(To page ll-193)

ldle Control System
ldle Air Control (lACl Vatve ('96 - 98 Dl6ys, Dl6yB engine with M/Tl
The scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem in the ldle Air Controt flAC) varvecircuit.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM inorder to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR ICl3A)
,flrcerh-:J iYEL/BLKI
!.__-,/ -lt(v)
-T-=
Wire side of female terminals
tAcv(BLK/
ELUI
ECM CONNECTOR A I32PI
Wire side oI lemal€ terminals
VALVE
6a10ll12t3r5t6l7t8t920232a
t*25&a2A3o
The MIL hss b€on repo.ted on.DTC P'l508 i. itorod.
Problem vorification:1. Do the ECM/PCM Reset Pro-cedure,Start the engine, and warm ituP to normal operating tem-perature.
Intormittont t!llur., sy.tcm b OKat thb tim6. Chsck fol poor con-ncctionr or loo3e wirot at C138(lAC valv.l.nd ECM.
ls DTC P1508 indicated?
Check for an opcn in the wiro(lGPl line):1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector.3. Turn the ignition switch ON (ll).
4. Measure vohage between bodyground and the IAC valve 2Pconnectorterminal No. 2.
R.prir opan in the wiro botwa.nIAC valv..nd PGM-FI main r.l.y.
Chock for an opon or sho in thewire (IACV linal:1. Turn the ignition switch OFFand reconnect the IAC valveconnector.2. Disconnect the ECM connectorA (32P).
3. Turn the ignit;on switch ON (ll).4. Measure voltage betweenbody ground and ECM con-nector terminal A12.
(To page 1l-195)
11-194

ldle Gontrol System
ldle Air Control (lAG) Valve ('99 - 00 Dl6Y8 engine with M/T, Bt6A2 enginel
[Fl50g l ]h" scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem in the ldle Air Controt AC) vatve- CtrCUtt.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM inorder to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR IC138'
la rcprI - {YEL/8LKI 2t--d,
Y-=
Wire side ot female terminals
Wire side of lemale terminals
VALVE
The MIL has boon r€oorted on.DTC P1508 is srored.
Probl6m verification:1. Do the ECM/PCM Reset Pro-cedure.2. Start the engine, and warm itup to normal operating lem-perature.
Intermittent tailure, system is OKat this timg. Check to. poor con-noctions or loose wires at C138{lAC valvel and ECM.
ls DTC P1508 indicated?
Ch6ck for an open in the wir€{lGPl lino}:1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector.3. Turn the ignition switch ON (ll).
4. Measure voltage between bodyground and the IAC valve 2Pconneclor termina I No.2,
Repair opon in the wire bgtwoenIAC valve and PGM-Fl main relay.
Check tof an open or short in thewire {IACV line}l1. Turn the ignition switch OFFand reconnect the IAC valve
2. Disconnect the ECM connectorB {25P).3. Turn the ignition switch ON (ll).
4. Measure voltage betweenbody ground and ECM conn€ctor terminal 823.
(To page 11-197)
1 1-1 96

ldle Control System
ldle Air Control (lAC) Valve ('96 - 98 A/T and Dl6Y7 enginel
The (Rotary) IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from theECM/PCM in order to maintain the proper idle speed,
BIMETAL
VALVESTOPPER
1P1509 Thescantool indicates Diagnostic Trouble Code (DTC) P1509: A problem in the idle Air Control (tAC)valve circuit.
ECM/PCM CONNECTOR A I32PIPGl IBLKI
IAC VALVE 3P CONNECIOR
IACV NIACV P
IGP
Terminal side of maleterminals
*: IACV N line
1 1-198
The MIL has b€€n roported on.DTC P1509 is stored.
Problem verification:1. Do the ECM/PCM Reset Proce-oure.2. Turn the ignition switch ON (ll).
Intermittent failura, systom ia OKat this time. Check tor poo. con-noctions or loose wires at C109llAC valve) and ECM/PCM.
ls DTC P1509 indicated?
Check for an opon in the wirer{PG lines):Measure voltage between bodvground and ECM/PCII connectorterminals A10 and A23 individu
Repair op€n in the wires betwoenECM/PCM and G101 llocated attho thermostat housing).
ls there more than 1.0 V?
Chock th€ ECM/PCM inpui volt-agel1. Turn the ignition switch OFF.2. Disconnect ECM/PCM connec-tor A (32P)from the ECM/PCM.3. Turn the ignition switch ON (ll).4. Measu re voltage betweenbody ground and ECM/PCMconnector terminals A14 andA13* individually.
Ch6ck th6 IAC valve:1. Turn the ignition switch OFF.2. Disconnect the IAC valve 3Pconnector,3, Measure resistance betweenIAC valve 3P connector termi-nal No.2 and terminals No. 1and 3 individually.
ls there 16 - 28 g?
Substitute a known-good ECM/PCM and recheck. lf symptom/indication goos away, replaceth€ origin.l ECM/PCM.
SHAFT
rAcv N loRNl*
(To page 11-199)
Wire side of lemale terminals
123a56El011
121314r5161718t9202:22321
272AA30
IACV P {BLK/BLUI

ldle Gontrol System
The (Rotary) IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the
ECM/PCM in order to maintain the proper idle speed.BIMETALHOLDER
BIMETAL
SHAFTVALVESTOPPER
ECM/PCM CONNECTOR B {25P}
(To page 11-201)
IAC VALVE 3P CONNECTOR
IACV NIACV P
ldle Air Control {lACl Valve ('99 - 00 A/T and Dl6Y7 enginel
YES
1P1509 lThescantool indicates Diagnostic Trouble Code (DTC) P1509:A problem inthe idleAirControl (lAC)valve circuit.
IGP
Terminal side of maleterminals
Sub3titute e known-good ECM/PCM .nd recheck. lf 3vmptom/indicalion goos away, replac6thc original ECM/PCM.
*: IACV N line
11-200
Tho MIL has b€en reported on.OTC P1509 is sto.ed.
Problem verilicationr1. Do the ECM/PCM Reset Proce-dure.2. Turn the ignition switch ON (ll).
Intermittont tailure, sy3tem i3 OKat thb time. Check for poor con'noctions or loose wiros at C109(lAC velvel and ECM/PCM.
ls DTC P1509 indicated?
Check for an oDen in the wilosIPG linesl:Measure voltage between bodyground and ECM/PCM connectorterminals 82 and 810 individually.
Ropail open in the wires be'tw€enECM/PCM .nd G101 llocated .tthe the.mostat housingl.ls there more than 1.0 V?
Check tho ECM/PCM input volt-age:1. Turn the ignition switch OFF.2. Disconnect ECM/PCM connec-tor A (32P)trom the ECM/PCM.3. Turn the ignition switch ON (ll).
4, Measure voltage betweenbody ground and ECM/PCMconnector terminals 86 and815* individually.
Chock the IAC v.lve:1. Turn the ignition sw;tch OFF.2. Disconnect the IAC valve 3Pconnoctor.3. Measure resistance betweenIAC valve 3P connector termi'nal No. 2 and terminals No. 1and 3 individually.
ls there 16 - 28 O?
Wire side of female terminals

ldle Control System
ldle Speed Setting
Inspection/Adiustmenl
'96, '97 Dl6Y5. '96 - 00 Dl5Y8 sngine with M/T
NOTE:
. Before setting the idle speed, check the following
items:- The MIL has not been reported on.- lgnition timing- Spark plugs- Air cleaner- PCV system
o (Canada) Pull the parking brake lever up. Start the
engine, then check that the headlights are off.
1. Start the engine. Hold the engine at 3.000 rpm withno load (taansmission in neutral) until the radiatorfan comes on, then let it idle.
2. Connect a tachometer.
3. Disconnect the IAC valve connector.
4.lf the engine stalls, restart the engine with the accel-
erator pedal slightly depressed. Stabilize the rpm at1,000, then slowly release the pedal until the engineidles.
Check idling in no-load conditionsr headlights. blowerfan. rear defogger, radiator fan, and air conditioner
are not operating.
ldle spsed should be:
450 1 50 rpm
11-220
Adjust the idle speed, if necessary, by removing thecap and turning the idle adjusting screw.
NOTE; After adjusting the idle speed in this step,recheck the ignition timing (see section 23).
lf it is out of spec, go back to step 4.
IDLE
6. Turn the ignition switch OFF.
7. Reconnect the 2P connector on the IAC valve, then
do the ECM reset procedure.
8. Restart and idle the engine with no-load conditionsfor one minute, then check the idle speed.
NOTE: (Canada) Pull the parking brake lever up.Start the engine, then check that the headlights areoff.
ldle sp€sd should b€:
670 i 50 rpm IUSA)750 t 50 rpm {Canada}
9. ldle the engine tor one minute with headlights {Low)ON. and check the idle speed.
ldle speed should be:
750 :r 50 rpm
10. Turn the headlights off. ldle the engine for oneminute with heater fan switch at Hl and air conditioneron, then check the idle speed.
ldle speed should be:
810150 rpm
NOTE: lf the idle speed is not within specification,see Symptom Chan on page 11-84.

t
t
I
'96.'97 D16Y5 engine with CVT,'96 - 00 D16Y8 ongins
with A/T and'96 - 00 Dl6Y7 €ngine
Adiust the idle speed using a Honda PGM Tester if pos-
sible. lf not, use the following procedure:
NOTEI
. Leave the IAC valve connected
. Betore setting the idle speed. check the following
items:- The MIL has not been reported on'
- lgnition timing
- Spark Plugs- Air cleaner- PCV system
1. Connect a tachometer.
2. Start the engine. Hold the engine at 3,000 rpm wirh
no load (in Park or neutral) until the radiator fan
comes on, then let it idle.
3. Check the idle speed with no-load conditions: head-
iights, blower fan, rear defogger, radiator fan, and
air conditioner are not operatlng
ldl€ spoed should be:
USA:
D16Y5 engine with CVT, D16Y7 engine with A/T'
Dl6YB engine with A/T:
700 :r 50 rpm (in E or El Positionl
D16Y7 engine with M/T:
670 i 50 rpm
Canada:
Dl6Y8 sngin€, Dl6Y7 engins:
M/T750 t 50 rpm
NT750 1 50 rpm (in E or El Position)
Adjust the idle speed, if necessary, by removing the
cap and turning the idle adiusting screw 1/2-turn
clockwise or counterclockwise
D16Y5, D16Y8 engine:
IDLEADJUSTING
Dl6f, ongine:
NOTE: When you remove the ACL housing, do not
disconnect the IAT sensor connector
After turning the idle adjusting scrow 1/2-turn'
check the idle speed again. lf it is out of spec, turn
the idle adjusting screw 1/2-turn agaan'
NOTE: Do not turn the idle adjusting screw more
than 1/2-turn without checking the idle speed'
ldle the engine for one minute with heater fan
switch at Hl and air conditioner on, then check the
idle speed.
ldle speed should be:
M/T810150 rpm
A/T. CvT810 t 50 rpm (in El or E Position)
NOTE:
. Do not turn the idle adjusting screw when the air
conditioner is on.
. lf the idle speed is not within specification. see
Symptom Chart on page 11-84 (cont'd)
11-221