INFORMATION SENSORS
1. MAP sensor
2. TP sensor
3. IAT sensor
4. ECT sensor
5. Heated oxygen sensor-1
6. VSS
7. Ignition coil
8. Battery
9. Distributor (CMP sensor)
10. A / C controller (if equipped)
11. CKP sensor
12. CTP switch (in ISC actuator)
13. Heated oxygen sensor-2CONTROLLED DEVICES
a : Fuel injector
b : EVAP canister purge valve
c : Fuel pump relay
d : Malfunction indicator lamp
e : ISC actuator
f : Radiator fan control relay
g : Ignitor
h : EFE heater relay
i : ISC actuator relayOTHERS
A : ECM (PCM)
B : Main relay
C : EVAP canister
D : Injector resistor
E : EFE heater
F : Electric load diode
G : Data link connector
ENGINE AND EMISSION CONTROL SYSTEM (TBI FOR G10) 6E1-5
The electronic control system consists of 1) various
sensors which detect the state of engine and driving
conditions, 2) ECM which controls various devices
according to the signals from the sensors and 3) vari-
ous controlled devices.
Functionally, it is divided into following sub systems:
Fuel injection control system
Idle speed control systemFuel pump control system
A/C control system (if equipped)
Radiator fan control system
Evaporative emission control system
EFE heater control system
Oxygen sensor heater control system
Ignition control system
A / T control system
ELECTRONIC CONTROL SYSTEM
ENGINE AND EMISSION CONTROL SYSTEM (TBI FOR G10) 6E1-7
CON-
NECTOR
C02TERMI-
NAL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26ECM ground
Power source (from main relay)
Blank
Blank
Blank
Blank
EVAP canister purge valve
Shift solenoid-B (A / T)
Shift solenoid-A (A / T)
Igniter
Idle speed control actuator
Fuel injector
Injector ground
Power source (from battery)
Power source (from main relay)
Idle speed control actuator relay
Malfunction indicator lamp
Immobilizer indicator lamp
Heater of HO2S-2
Radiator fan relay
Fuel pump relay
Main relay
Blank
Idle speed control actuator
EFE heater relay
Injector groundC031
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22Data link connector
Vehicle speed sensor (+) (A / T)
Vehicle speed sensor (M / T)
Transmission range sensor (switch)“2”
Transmission range sensor (switch)“N”
Transmission range sensor (switch)“P”
Blank
Blank
Heated oxygen sensor-2
Blank
Fuel level sensor (gauge)
Blank
Data link connector
Vehicle speed sensor (–) (A / T)
Transmission range sensor (switch)“L”
Transmission range sensor (switch)“D”
Transmission range sensor (switch)“R”
A / C ON (output) signal for A / C control module
(if equipped)
Electric load signal
A / C (input) signal from A / C control module
(if equipped)
Ignition switch
Blank
Blank CIRCUITCON-
NECTORTERMI-
NALCIRCUIT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16Power source for sensors
Camshaft position sensor (+)
Crankshaft position sensor (+)
Closed throttle position switch
Manifold absolute pressure sensor
Throttle position sensor
Engine coolant temp. sensor
Heater of HO2S-1
Sensor ground
Camshaft position sensor (–)
Crankshaft position sensor (–)
EFE heater (monitor)
Heated oxygen sensor-1
Intake air temp sensor
Power steering pressure switch (if equipped)
Engine start signal circuit
C01
1. CMP sensor (in Distributor)
2. CKP sensor
3. TP sensor
4. MAP sensor
5. ECT sensor
6. IAT sensor
7. HO2S-1
8. HO2S-2
9. Transmission range switch (A / T)
10. VSS (A / T)
11. A / C control module (if equipped)
12. Heater blower switch
13. Fuel level sensor
14. Speedometer
15. P.SP switch
16. Rear defogger switch
17. Light switch
18. DLC
19. Fuel injector20. Injector resistor
21. Conister purge valve
22. Fuel pump relay
23. Rediator fan relay
24. EFE heater relay
25. ISC actuator relay
26. ISC actuator
27. Ignition coil
28. Igniter
29. Immobilizer indicator lamp
30. MIL
31. Main relay
32. Shift solenoid A (A / T)
33. Shift solenoid B (A / T)
34. Starter motor
35. Ignition switch
6E1-12 ENGINE AND EMISSION CONTROL SYSTEM (TBI FOR G10)
1. Fuel injector wire
2. Fuel injector
3. Upper O-ring
4. Lower O-ring
5. Throttle upper body
6. Gasket
7. Throttle lower body
8. ISC actuator
9. TP sensor
10. Injector sub wire coupler
11. O-ring
12. Injector wire cover
CAUTION:
As throttle stop screw and throttle lever screw are fac-
tory adjusted precisely, don’t remove or adjust them.
Throttle
stop
screw
Throttle lever
screwPositive
terminal Negative
terminal
Viewed from “A”
1. Throttle body
2. Vacuum nozzle
1. Injector coupler
2. TP sensor
3. Water hose
4. Vacuum hose
5. ISC actuator
6. Fuel return hose
7. Fuel feed hose
THROTTLE BODY
ON-VEHICLE INSPECTION
Check that throttle valve lever moves smoothly.
Vacuum passage inspection.
With fingers placed against vacuum nozzle, increase engine
speed a little and check that vacuum is applied.
REMOVAL
1) Relieve fuel pressure, referring to Section 6.
2) Disconnect battery negative cable at battery.
3) Remove air cleaner assembly referring to Section 6A.
4) Drain cooling system.
5) Disconnect following wire harness couplers:
TP sensor
Fuel injector
ISC actuator
6) Disconnect following hoses from throttle body.
Fuel feed and return hoses
Engine cooling water hoses
Vacuum hoses
7) Disconnect accelerator cable from throttle valve lever and cable
bracket.
8) Remove throttle body from intake manifold.
ENGINE AND EMISSION CONTROL SYSTEM (TBI FOR G10) 6E1-13
1. Fuel injector wire
2. Fuel pressure regulator
3. TP sensor
4. Screws
5. ISC actuator
1. Injector chamber
2. Fuel return passage
3. Fuel feed passage
4. Vacuum passage for fuel pressure regulator
5. Vacuum passage for MAP sensor
6. Air induction passage
7. Vacuum passage
8. Fresh air passage
DISASSEMBLY
NOTE:
Be sure not to remove either fuel pressure regulator or idle
speed control actuator from throttle body. They are factory
adjusted precisely.
Be sure to replace gaskets and O-rings as well as worn or
damaged parts.
While disassembling and assembling throttle body, use spe-
cial care not to deform levers on throttle valve shaft or cause
damage to any other parts.
1) Remove fuel injector from throttle body according to procedure
described in FUEL INJECTOR REMOVAL.
2) Remove TP sensor.
3) After removing screws, separate upper and lower bodies.
CLEANING
Clean passages and fuel injector chamber by blowing compressed
air.
NOTE:
TP sensor, fuel pressure regulator, fuel injector, ISC actua-
tor, other components containing rubber (resin) or throttle
valve shaft seal must not be placed in a solvent or cleaner
bath. Chemical reaction will cause these parts to swell, hard-
en or get distorted.
Don’t put drills or wires into passages for cleaning. It causes
damage in passages.
ENGINE AND EMISSION CONTROL SYSTEM (TBI FOR G10) 6E1-15
1. Injector coupler
2. TP sensor
3. Water hose
4. Vacuum hose
5. ISC actuator
6. Fuel return hose
7. Fuel feed hose
1. Injector coupler
Good No good
2) Install throttle body to EFE heater and tighten bolts to specified
torque.
Tightening Torque
(a): 23 N
.m (2.3 kg-m, 17.0 lb-ft)
3) Install accelerator cable to throttle valve lever and cable brack-
et.
4) Connect fuel, cooling water and vacuum hoses to throttle body,
and clamp securely.
5) Connect TP sensor and injector couplers securely.
6) Refill cooling system referring to Section 6B.
7) Connect negative cable at battery.
8) With engine “OFF” and ignition switch “ON”, check for fuel
leaks around fuel line connection.
9) Install air cleaner assembly referring to Section 6A.
10) Upon completion of installation, start engine and check for fuel
leaks and engine coolant leaks.
Adjust cable play to specification according to procedure de-
scribed in ACCELERATOR CABLE ADJUSTMENT.
FUEL INJECTOR
ON-VEHICLE INSPECTION
1) With battery negative cable disconnected, disconnect injector
coupler.
2) Connect ohmmeter to each injector terminal and measure resis-
tance.
Resistance of injector: 0.5 – 1.5 Ω at 20C (68F)
If resistance is out of specification, replace fuel injector.
3) Connect injector coupler.
4) Remove air cleaner assembly without disconnecting IAT sensor
coupler.
5) Check that fuel is injected out in conical shape from fuel injector
when cranking or running engine.
If no fuel is injected, check wiring harness for continuity and cou-
plers for proper connection referring to “DIAGNOSTIC FLOW
TABLE B-1”.
If fuel is not injected out in conical shape, replace injector.
6) Check injector for fuel leakage after injection is stopped (i.e., af-
ter cranking or engine stop).
Replace if leakage exists.
Fuel leakage: Less than 1 drop/min.
7) Install air cleaner assembly.
6E1-26 ENGINE AND EMISSION CONTROL SYSTEM (TBI FOR G10)
1. Throttle body
FUEL PUMP RELAY
INSPECTION
1) Disconnect negative cable at battery.
2) Remove fuel pump relay (1) from relay box (2).
3) Structure of fuel pump relay is the same as that of main relay.
Check its resistance and operation using the same procedure as
that for main relay.
If found defective, replace.
FUEL INJECTOR RESISTOR
INSPECTION
1) With ignition switch OFF, disconnect resistor coupler.
2) Check resistor (1) for resistance.
Resistance: 1.9 – 2.1 Ω at 20C, 68F
If check result is not satisfied, replace.
FUEL CUT OPERATION
INSPECTION
NOTE:
Before inspection, check to make sure that gear shift lever is in
neutral position (with A/T model, selector lever in “P” range), A/C
is OFF and that parking brake lever is pulled all the way up.
1) Warm up engine to normal operating temperature.
2) While listening to sound of injector by using sound scope (2) or
such, increase engine speed to higher than 3,000 r / min.
3) Check to make sure that sound to indicate operation of injector
stops when throttle valve operation of injector stops when
throttle valve is closed instantly and it is heard again when en-
gine speed is reduced to less than about 2,000 r / min.
IDLE SPEED CONTROL SYSTEM
SYSTEM INSPECTION
NOTE:
Before inspection, check to make sure that:
–Gear shift lever is in neutral position (with A / T vehicle, selec-
tor lever in “P” range) and that parking brake lever is pulled
all the way up.
–Battery voltage is higher than 11 V.
–Throttle valve moves smoothly.
–Ambient temperature is higher than 0C (32F)
6E1-32 ENGINE AND EMISSION CONTROL SYSTEM (TBI FOR G10)
RH
LH
EMISSION CONTROL SYSTEM
EVAPORATIVE EMISSION CONTROL SYSTEM
EVAP CANISTER PURGE INSPECTION
NOTE:
Before inspection, check to make sure that gear shift lever is
in neutral position (with A / T model, selector lever in “P” range)
and that parking brake lever is pulled all the way up.
1) Disconnect purge hose from EVAP canister.
2) Place finger against the end of disconnected hose and check
that vacuum is not felt there when engine is cool and running at
idle speed.
3) Connect purge hose to EVAP canister and warm up engine to
normal operating temperature.
4) Disconnect purge hose from EVAP canister.
5) Also check that vacuum is felt when engine is running at idle
speed.
NOTE:
The EVAP canister purge system does not perform purging
(vacuum is not detected at the purge hose) unless the en-
gine is sufficiently warmed up and the heated oxygen sen-
sor is activated fully. Also, when the purge hose is discon-
nected in Step 4), the air is drawn into the purge line. As a
result, ECM detects a change in the purge gas concentra-
tion and sometimes stops purging but this indicates noth-
ing abnormal.
If check result is not satisfactory, check vacuum passage, hoses,
EVAP canister purge valve, wire harness and ECM.
VACUUM PASSAGE INSPECTION
Start engine end run it at idle speed. Disconnect vacuum hose from
EVAP canister purge valve. With finger placed against hose discon-
nected, check that vacuum is applied.
If it is not applied, clean vacuum passage by blowing compressed
air.
VACUUM HOSE INSPECTION
Check hoses for connection, leakage, clog and deterioration. Re-
place as necessary.
ENGINE AND EMISSION CONTROL SYSTEM (TBI FOR G10) 6E1-33
EVAP CANISTER PURGE VALVE INSPECTION
WARNING:
Do not suck the air through valve. Fuel vapor inside valve
is harmful.
1) With the ignition switch OFF position, disconnect coupler from
EVAP canister purge valve.
2) Check resistance between two terminals of EVAP canister
purge valve.
Resistance of EVAP canister purge valve:
33 – 39 Ω at 20C (68F)
If resistance is as specified, proceed to next operation check.
If not, replace.
3) Disconnect vacuum hoses from intake manifold and its pipe.
4) With coupler disconnected, blow into pipe “A”. Air should not
come out of pipe “B”.
5) Connect 12 V-battery to EVAP canister purge valve terminals.
In this state, blow pipe “A”.
Air should come out of pipe “B”.
If check result is not as described, replace canister purge valve.
6) Connect vacuum hoses.
7) Connect EVAP canister purge valve coupler securely.