1998 ACURA INTEGRA firing

PGM-FI System
Random Misfire
1T0-500 1 a nd Fo-30ittrrousFF0304-lThB scan tool indicates Diagnostic Trouble Code {DTC) P0300 and some of
P0301 - P0304: Random misfire.
Doscription
Misfir; detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluciuation sensor which
is attached to the crankshsft.
lf misfiring strong enough to damage the catalyst is detected, the MIL will blink during iho time of its occurrence, and DTC
p0300 and some of DTCS p0301 through P0304 will be stor€d. Then, after misfire has ceased, the MIL will come on.
lf misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTC
PO3O0 and some ot DTCS P0301 through P0304 will be stored
NOTE: lJ some of the DTCS listed below are stored at the same time as a misfire DTC, troubleshoot those DTCS first. then
troubleshoot the misfire DTC.
P0171, P0172: Fuel metering
P0505: ldle Control SYstem
P1361, P1362: TDC sensor
P1381. P1382: CYP sensor
P1508: IAC valve
Possible Cause
. Fuel pump insufficient fuel pressure. amount of flow
. Fuel line clogging, blockage, leakage
. Fuel {ilter clogging
a Fuel pressure regulator stuck open
. Distributormallunction
o lgnition coil wire open, leakage
. lgnition control module malfunction
. Valves carbon deposit
a Compression low
. IAC valve malfunction
. Fast idle thermo valve malfunction
o Fuel does not meet Owner's Manual spec., lackotfu€l
. VTEC system malfunction
Troubleshooting
By test-driving, determine the conditions during which misfire occurs. Depending on these conditions, test in the order
described in the table below.
Fuel
pressure
Distributor
and lgnition
wires
tcMIAC ValveValve
Clearance
wEc
System
11118section 23section 231 1- 100section 6section 6
Only low rpm and
loao@o@@
Only acceleratingo@o
Only high rpm and
loado@@@o
Not specificationo@@@@
NOTE: lf misfire doesn't recur, some possible causes arefuel that doesn't meet owner's manual spec, lackoffuel, carbon
deposits on spark plug, etc.
11-78

Misfire Detected in One Cylinder
I P0301 The scan tool indicates Diagnostic Trouble Code (DTC) PO3O1:Cylinder 1 misfire detected.
[F03021 1;," """n tool indicares Diagnostic Troubte Code (DTC) pO3O2: Cylinder2 misfire detected.
P0303 | ths sssn tool indicates Diagnostic Trouble Code (DTC) PO3O3: Cylinder3 misfire detected.
i P0304 | tne scan tool indicates Diagnostic Trouble code {DTC} PO3O4: Cylinder 4 misfire detected.
Doscription
Misfire detection is accomplished by monitoring the crsnkshaft speed with the crankshaft speed fluctuation sensor whichis 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 DTCP0301, P0302, P0303 or P0304 will be stored. Then, after the m;sfire has ceased, the MIL witt come on.lf misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTCP0301, 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, thentroubleshoot the misfi.e DTC.
P0107, P108, P1128,P'1129: MAP sensor
PO171, PO172t Fuel metering
P0505; ldle control system
P1259: WEC System
P1361, P1362: TDC sensor
P138'1, P1382: CYP sensor
P1519: IAC valve
Possibls Caus6
. Fuel injector clogging, fuel leakage, air leakage
. Fuel injector circuit open or shoned. Spark plug carbon deposits, fouling, malfunction. lgnition wires open, leaking
. Distributor malfunction
. Compression low
a Valve clearance out of spec.
(cont'd)
11-79

PGM.FI
Misfire
System
Detected in One Cylinder (cont'd)
)
Troubleshooting Flowchart
ff
i
)
NOTE:.lf there is no freeze data of misliring,just clear the DTC.'lf there is no freeze data of misfiring,test drives under various conditions
The MIL has b6€n reported on.DTC P0301, P0302, P0303 0rP0304 is indicated.
Check the fuel iniector function:Stan the engine, and listen for aclicking sound at the fuel injectorin the problem cylinder.
Check for an open or shon in theharness between ECM and thefUel injector.
Repair open or short in the wiro.
- Replace tho luel inisctor.- Sub3titute a known-goodECM and rach€ck. It symptom/indicrtion 90e3 away, replacethe original ECM.
Problem ve.ification:1. After checking the freeze data,do the ECM Reset Procedure.2. Exchange the spark plug fromthe problem cylinder with oneof another cylinder.3. Connect the SCS service connector.4. Test-drive the car several timesin the range of the treeze data.
(To page 11-81)

(From page l1-80)
Iniermittenl misfire due lo sparkplug fouling, otc. Iti.ing is OK atthis timo).
Does the misfire occur in theother cylinder whose spark plugwas exchanged?Replace the faultv spark plug.
Check for tuel ini€ctor maltunc-taon:1. Exchange the fuel injectorfrom the problem cylinderwith one from another cylin'der.2. Let the engine idle lortwo min-uteS.3. Test-drive the car sevoraltimesin the range ofthe treeze data.
Int€rmitt€nt mislire due to badcontact in tho tuel iniector con-nector lfiring is OK at thb time).
Does the misfire occur in theother cylinder whose tuel injectorwas exchanged?Replace the laultv tuel iniector.
Check the following items- Cylinde. lerk-down- Compaession- Crankshafl Position (GKPI son-
NOTE: lf there is no freeze data of misfirang, test drives under various condi-trons are necessary.
1 1-81