engine ground HONDA INTEGRA 1994 4.G User Guide

PGM-FI System
System Description
ENGINE CONTROL MODULE (ECMIOUTPUTS
PGM-Fl System
The PGM-Fl system on this model is a sequential multipon fuel injection system,
Fuol Iniector Timing and Duration
The ECM contains memories tor the basic discharge durations at various engine speeds and manifold pressures. Thebasic discharge duration, after being read out from the memory, is turther modilied by signals sent from vanous sensofsto obtain the final discharge duration.
ldle Air Control
ldle Air Control Valve (lAC Vatve)
When the engine is cold, the A/C compressor is on, the transmission is in gear (A/T only) the brake pedal is depressed,the P/S load is high, or the alternalor is charging, the ECM controls current to the IAC Valve to maintain correct idle soeed.
lgnition Timing Controla The ECM contains mamories for basic ignition timing at various engine speeds and manifold pressures. lgnition timingis also adjusted for engine coolant temperature.a A Knock Control System is also used. when detonation is detected by the knock sensof. the ignition timing is retarded(B18Cl engine).
Other Control Functions
1. Starting Control
When the engine is started. the ECM provides a rich mixture by increasing fuel injector duration.2. Fuel Pump Control
a When the ignition switch is initially turned on, the ECM supplies ground to the PGM-Fl main relay that suppliescurrent to the fuel pump tor two seconds to pressurize the tuel system.a When the engine is running, the ECM supplies gfound to the PGM-Fl main relay that supplies current to the fuel pump.a When the engine is not running and the ignition is on, the ECM cuts ground to the PGM-FI main relav which cutscurrent to the fuel pump.
TDC/CKP/CYP Sensor
MAP Senso.
ECT Sensor
IAT Sensor
TP Sensor
HO2S
vss
BARO Sensor
ELD
Starter Signal
ALT FR Signal
Air Conditioning Signal
A/T Gear Position Signal
Battery Voltage {lcN. 1)
Brake Switch Signal
PSP Switch Signal
Knock Sensor'
VTEC Pressure Switchr
Fuel-lnjectors
PGM-FI Main Relay (Fuel Pump)
MIL
IAC Valve
A/C Compressor Clutch Relay
Radiator Fan Relav
Condenser Fan Relav
ALT
rcM
EVAP Purge Control Solenoid
HO2S Heater
VTEC Solenoid Valve'
IAB Control Solenoid Valve*
lFuet tnjector Timing and Duration]
I Electr..l"ldle Contr;il
Fit'e' contr; Funcrfit
l6tio; Ttntrlg c..trol
tEcM aack-,rp Functiorlsl
': 818C 1 €ngine
11-40

3. Fuel Cut-oft Control
a During deceleration with the throttle valve closed, current to the {uel injectors is cut otJ to improve fuel economy
at speeds over tollowing rpm:
. 8188l engine: 91O tpm (Canada model: 1,O50 rpm)
. 818C1 engine: 95O tpm (Canada model: l,O5O rpm)
a Fuel cut-olf action also takes place when engine speed exceeds, 7,O0O rpm {81 8B1 engine), 8,1O0 rpm (B 18Cl
engine), regardless oI the position of the throttle valve, to protect the engine from ovet-revving.
A/C Compressor Clutch Relay
When the ECM receives a domand for cooling trom the air conditioning system, it del8ys the compressor from being
enetgized, and enriches the mixture to assure smooth transition to the A/C mode.
Evaporative Emission (EVAP) Purge Control Solenoid Valve
When the engine coolant tempersture is below 163oF {73"C), the ECM supplies a ground to the EVAP pu.ge control
solenoid valve which cuts vacuum to the EVAP purge control diaphragm valve.
Intake Air Bypsss (lAB) Control Sol€noid Valve
When the engine rpm is below 5,750 rpm, the IAB control solenoid valve is activated by a signal from the ECM,
intske air flows through the long intake path, then high torque is delivered. At spaeds highe. than 5,750 rpm, the
solenoid valve is deactivated by the ECM, and intake air flows through the short intake path in order to reduce the
resistance in airflow.
ECM fail-safe/bEck-up Functions
1. Fail-sate Function
When an abnormality occurs in a signal from a sensor, the ECM ignores that signal and assumes a pre-progtammed
value tor that sensor that allows the engine to continue to run.
Back-uD Function
When an abnormalitv occurs in the ECM itself, the fuel iniectors are controlled by a back-up citcuit independent of
the system in order to permit minimal driving.
Self-diagnosis Function IMaltunction Indicator Lamp {MlL)1
Wh6n an abnormality occurs in a signal from a sensor, the ECM supplies ground for the MIL and stores the code
in erasable memory. When the ignition is initially turned on, the ECM supplies ground tor the MIL tor two seconds
to check the MIL bulb condition.
Two Trio Detection Method
To prevent tals€ indications, th€ Two Trip Dstection Method is used for the HO2S and fuel metering-related self-
diagnostic tunctions. When an abnormslity occurs, the ECM stores it in its memo.y. Wh€n the ssme sbnormality
recurs alter the ignition switch is turned OFF and ON ag8in, the ECM informs the driver by lighting the MlL.
However, to ease troubleshooting, this function is canc€ll€d when you short the service check connector. The MIL
will then blink immedistelv when an abnormality occurs.
4.
6.
2
4.
11-41

Th. ll.lfunction Indicltor Lamp
lMlll at!y3 on o. cornaa on alt6ltwo aacond!.
Connect the SCS short connectorto th6 sorvice check connector(see page 11-34).
Turn the ignition switch ON.
Go to iolfdiagnostic Proceduros(se€ pago 11-34).Does the MIL indicate anv Oi-agnostic Trouble Code (DTC)?
Romove th€ SCS shon connectorlrom the service ch€ck connector.
Turn the ignition switch OFF.
Try to start the engine.
Connect the test harness betweenthe ECM and connectors (see
page 11-37).
Turn the ignition switch ON.
Measure voltage botween D4 (+ )terminal and D22 { - ) terminal.
connect the SCS shonconnector to servlcecheck connector.ls there approx. 5 V?
Ropair shon to body g.ound inBRN/WHT wire betwoon th6 ECMlD4) end sorvlco chock connocto?.Measure voltage be_tween D4 {+} terminaland body ground.
- R6pair open in BRN/WHT witobotwoon EcM lD4) and s6rv-ice chock connactor.- Repoir opon in BLK wiro bo-twoon 36rvi@ chock connectoaand G4Ol.
ls there approx. 5 V?
InsDoct ECU {ECM) 115 A) tuse inth6 undeFhood luse/relav box.
- Rsolaco ECU {ECM} (15 Allus€.- R6pair shon in YEL/WHT wilobotw6on ECU lEcMl 115 A)fuso and PGM-FI main rolay.
Remove the scs shortConnector from theservice check con-nector.
ls the luss OK?
NOTE:
a When there is no code stored, the MIL willstay on if the service check con-
nector is shorted.
a tf this svmotom is intermittent, check for:
- A loose ECM fuse (15A) in the under-hood tuse/relay box
- A loose No. 24 fuse (ACG) (ALT) ( 1 5A: B1 8B 1 engine, 2OA: B18C 1 en-
gine) in the under-dash fuse/relay box- An intermittent short in the BRN/WHT wire between the ECM (D4) and
the service check connector- An intermittent oDen in the BLK wire between the service check con-
nector and G4O1- An intermittent shon in the GRN/ORN wire between the ECM (A 13) and
the gauge assembly.- An intermittent short in the YELMHT wire between the ECM (D19) and
the MAP sensor- An intermittent short in the YEL/BLU wire between the ECM (D20) and
the TP sensor
o ooooo ooo ooo o loooooooo liii:$A$.Ps,l o oo ooo ooooo
o oooo ooo o o ooo I oooooooooooooooooo
D4 (+)
l"oo,o'.
D22 t-l
uu,l
'NOTE: After repair, disconnect the SCS ShortConnsctor, test drive the car, and recheckthe MIL
lor a code.
(cont'd)
(To page 1 'l -44)lTo page 1 1-44)
11-43

(From page 1 1-43)
Inspect the No. 24ACG {ALT) (lG)(15 A: 81881 engine, 2OA:818C1 enginel fuse in the under-dash fuse/relav box.
- R.pllr .hon in BLK|rEL wlr6batr.v€qr undariair luro/Fbybox lnd FGM-FI m.in .obv.- noebco lto. 24 ACG {lG) nLT)(15 A: 81881 ongin., 2OA:Bl8Cl onein.l tu!6.
ls the fuse OK?
Turn the ignition switch ON.
Disconnect the 3P connector oteach sensor one al a time:. MAP sensor. TP sensor
Rcplaoo thg lgnlor that caur6dth. llght to Oo out.Does the MIL remain ON?
Turn the ignition switch OFF.
connect the test harness.Disconnect the "D" connectorfrom th€ ECM only, not the mainwire harness (see page 11-37).
Check tor continuity betweenbody ground and D19, O2O ter-minals,
- Bapai? rhod ro body g.ound inYEL/WHT wi.e boiwoon ECM(Dl9) .nd MAP ..n3or.- R.p!k shon to body ground inYEL/BLU wire b.lwo6n ECM(O2Ol .nd TP 3on!or.
Reconnect all tho sensor con-necrors,Reconnect the "D" connector torhe ECM.
Turn the ignition switch ON.
{To page 11-45}
System
Control Module (ECMI (cont'dl
PGM-FI
Engine
Dt9I
I oooooooooo ooo I oooooooo I omoool o oooooooooo | |I ooooooooooooo I oooooooo 1o('oe(lo I ooooooooooo | |-lD2O I
\-.J
Continuity?
(From page 11-43)
Disconnect "A" con-nector from the ECM.
Subrtltute r knowngood ECM.nd rochock. ll lymptom/indics-tlon g@a rw!y, rephco tho origi-n.l ECM.
ls the MIL ON?
Ropair short to bodygiound in GRN/ORNwir6 botwoon tho ECMlA131 6nd MlL.
11-44

Measure voltage between YEL/WHT {818C1 engine), YEL/RED(B188'1 engine) {+ ) terminal andbodv ground.
Measure voltage between YEL/WHT (818C1 engine), YEL/RED{B1881 engine) (+ } terminal andGRN/WHT (- ) terminal.
ls there approx. 5 V?
Repair opon in GRN/WHT wir6 botweonECM lD2l l and thoMAP sonsor,
Turn the ionition switch OFF.
ls there approi. 5 V?
Connect the test harness "D"
connector to the ECM only, nottothe main wire harness {see page11,37).
Turn the ignition switch ON.
Measure voltage betweon wHT/YEL (+ ) terminal and GRN/WHT{- } terminal.Measure voltage between D19{+} terminal and D21 {-}termrnat,
ls there approx. 5 V?
Bepair open in YEL/WHT wi.e be-tw€6n ECM lD19) and tho MAPaon30t.
ls there approx. 5 V?
Substitule s known-good ECMand rechock. ll symptom/indica'tion goes away, replac€ tho oiigi'nal ECM.Turn the ignition switch OFF.
Reconnecl the 3P connector tothe MAP sensor.
Connect the test harness betweenthe ECM and connector (see page1 1-371.
Turn the ignition switch ON.
11,52)
{To page 11-54}lTo page I l-54)
(cont'd)

PGM-FI System
Electrical Load Detector (ELDI
tft;-]/ The Maltunction Indicaror Lamp (MlL) indicatss Diagnostic Trouble Code IDTC) 20: A probtem in-Li!- tne Electrical Load Detecror {ELD} circuit.
With lho SCS lhon connectolconnoctod {ree pago 11-34}, cod.20 is indicatod.
Do the ECM B6set Procedurs {seepage 1 'l-35).
Start engine and keep engin€speed at idle.Turn on headlights.
lntennlna tlllure, lyrtom lt Ol(!t irl. dm. (lgtt driv. mly bona@raaryl.Chrck for Door connactlona oaloota wiro. rt C218 IELD, lndEctrt.
Ooes the MIL indicato code 20?
Romove the undgr-hood fusg/relay box and remove the tus6/relav box lowet cover.
Turn lhe ignition switch ON.
Measure voltage betw€on BLK/YEL (+l terminal and BLK (-)terminal.
Msasuro voltag€ b€tweon BLK/Y€L {+) terminal snd bodvground.ls there bartory voltagel
Rcpir oo.n in BLK wir.batwaan lha 3P connrc-tor lnd G2Ol {loc.t.dtroit ot angh|. comprn-m.r dghl .ld.l,
B.p.lr op.n in BLKrYEL wlrr b.-tw..n o.24ACG (ALn flcl115A: Bl88l .ngln!, 20 A:818C1cnginol fu!. In thr und.r{..htu.o/r.lly bor lnd tho 3P con-rcclo?.
View tromwire side
BLK (-)
(To page 11-7'l)
GRn/iED I - |
BLK/YEL I + I
11-70

PGM-FI System
Knock Sensor (KS) tB18C1 enginel
ml- nl: The Malfunction Indicator Lamp (MlL) indicates Diagnostic Troubte Code (DTC) 23: A probtem inthe Knock Sensor (KS) circuit.
a6l--fzt.i--1/.---r+\
ware sido
o ooooo ooo ooo o looooooooo oooo ooo oo ooo I oooo oooo
11-74
- The MIL h6s boon r6port6don.- With th6 SCS ahort connec-tor connoctod (soe pago11-341, codo 23 is in-dicrtod.
Oo the ECM Reset Proceduro (seepage 11-35).
Start the engine. Hold the engineg!-3,Opq rpm with no load {A/T in
Lryl orlPlposirion, M/T in neurra until the radiator fan comes on,then let it idle.
Hold the engine at 3,0O0-4,000rpm for 10 seconds.Intomittor failure, ay5-t.m is OK at this tim6(teat drivo mav bonec€saary,.Chock tor Door connec-tion3 or loo3o wlaos etC222 {locatod 6r ghrshock tow6r), Cl33(KSl and ECM.Turn the ignition swirch OFF.
Connect the test harness to themain wire harness only, not to theECM (see page 1 1-37).
Check for continuity between D3terminal and body ground.
Ropdr short in RED/BLUwiro b€tweon ECM {D3land ths Ks.
(To page 11-75)

PGM-Fl Main Relay
Doscription
The PGM-Fl main relav actuallv contains two individual
rerays.
This relay is located at the lett side of the cowl.
One relay is energized whenever the ignition is on which
supplies the battery voltage to the ECM, power to the
fuel injectors, and power for the second relay.
The second relay is energized for 2 seconds when the
ignition is switched on, and when the engine is running,
to supply power to the fuel pump.
PGM-FIMAIN RELAY
FUEL PUMP
Relay Testing
NOTE: lf the car stans and continues to r
Fl main relay is OK.
1. Remove the PGM-Fl main relay.
2. Attach the battery positive terminalto
minal and the battery negative termir
1 terminal of the PGM-FI main relay. T
continuity between the No. 5 terminal
minal of the PGM-FI main relay.
a lf there is continuity, go on 10 ste
a lt there is no continuity, replace the
relay and retest.
To lGN. I
To GROUND
To ST. SWITCH
To ECM {47}
Attach the battery positive terminalto
minal and the battery negative termil
3 terminal of rhe PGM-Fl main .elav. Tl
there is continuity between the No. ;
No.6 terminal of the PGM-Fl main re
a lf there is continuity, go on to st€
a lf there is no continuity, replace th€
relay and retest.
Anach the battery positive terminalto
minal and the battery negative termil
1 terminalof the PGM-Fl main relay, Tl
there is continuity between the No. :
No. 4 te.minal of the PGM-Fl main r
a It there is continuitv, the PGM-FI mi
a lf there is no continuity, replace th(
relav and retest.
No.2
run, the PGM-
nalto the No. 2 ter-
terminal to the No.
lay. Then check for
minal and No. 4 ter-
to step 3.
ce the PGM-Fl main
8Ar C)
ECM {425, 81)
J To FUEL PUMP
inalto the No. 5 ter-
terminsl to the No.
ay. Then check that
No. 7 terminal and
ain relay.
to step 4.
ce the PGM-Fl main
inal to the No. 6 ter-
terminal to the No.
ay, Then check that
No. 5 terminal and
nain relay.
-Flmain relay is OK.
ce the PGM-Fl main
(cont'd)
11-111

Intake
Intake
Air
Air
System
Bypass (lAB) ControlSystem tBl8C1 enginel (cont'dl
Troublcahooting
VACUUII PUMP/GAUG€A973X-041-XXXXX
fromwiro haanasid€
PI{K/BLU I-I
YEI/aLK l+l
tA8 COI{TROLDIAPHRAGM
Insp€ction of IAB Conltol Sytt.m
Start engino and allow to idle.
R€move # 13 vacuum hose tromthe IAB control diaph.agm andconnect vacuum gauge to thehose.
R€move # 12 vacuum hose fromth€ IAB vacuum tank, then checktor vaccum at the IAB vacuumtank.
Rcplir lh. block.g. otvacuufi laak boiwaaotha IAB vacuum tanklnd th. intlk m!ni-fold.
Disconnect the 2P conn€ctor lromthe IAB control solenoid valve.
Measure voltage betweenYEL/BLK (+l torminal andPNK/8LU l-) terminsl.
ls thoro battery voltage?
Measure voltage b€twee nBLK^|/EL (+) torminal and bodyground.
IAB CONTBOLSOLENOID VALVE

(From page 1 1-124)
Raise engine speed to above6,000 rpm.
Disconnect the 2P connector tromthe IAB control solenoid valve.
Turn the ignition switch OFF.
Check for continuity to ground onthe PNK/BLU wire.
Ropair short to g.ound
at PNK/BLU wiro bo-two6n ECM {A17) andtho 2P connector.
ls there continuity to ground?
Substituto a known-good ECMand racheck. It symptom goos
swsy, roplace tho original ECM.
{From pago 1 1-124}
Repsir op6n in YEL/BLKwiro botwoon tho 2Pconnector and FGM-FImain relaY.
ls there battery voltage?
Turn the ignition swirch OFF.
Connect lhe test harness betweenthe ECM and connectors lseepage 11-37).
Turn the ignition switch ON andconnect a lumper wke betweenECM (A17) terminal and ECM
{A26) terminal.
Ropaiiopon inP K/BLUwiao botwoen ECM
lAl7l and tho 2P con-nectot.
Ooes the solenoid valve clickwhen the jumper is con-nected?
Sub3titute a known-good ECMand rechock. lf symptom/indica-tion goos away, r6place tho origi-nal ECM.
Check lor vacuum at #'l3 vacu-um hose.
IAB control syst6m is OK.
11-125