
OUTLINE F 
SPECIFICATIONS 
Item 
Idle speed*1 *2 
Ignition timing*2 
Fuel pump 
Maximum outout Dressure Engine 
rpm B6 SOHC 
6O--80  BTDC 1 
kPa (ka/cm’. osi1 1 BP SOHC 
700-800 
4O---6O BP DOHC 
90-l 1 O 
441-637 (4.5-6.5. 64-92) I 
I Fuel filter I 
Type Low-pressure side Nylon element (in fuel pump) 
High-pressure side Paper element 
Pressure reaulator 
Regulating pressure kPa (kg/cm’, psi) 1 265-314 (2.7-3.2, 38-46) 
I lniector I 
Type Type of drive 
Resistance 
Idle speed control (ISC) valve 
TvDe , , 
t Resistance 
Purge control solenoid valve 
Resistance 
Water thermosensor n High-ohmic 
Electromechanical 
12-16 
Rotarv 
n I II-13 I 
n 1 23-27 
1 -20% I -4OFj 1 14.6-17.8 
Resistance k62 2ooc i 68OF) 2.21-2.69 
40°C (104OF) 1.0-l .3 
80°C (176OF) 0.29-0.35 
Airflow meter 
E2++Vs 
E2-Vc Fully closed 
Fully open 20-600 
20-l ,000 
200-400 
Capacity liters (US gal, Imp gal) 1 Hatchback 50 (13.2, ll.O), PROTEGE ,... 55 (14.5, 12.1) 
I Air cleaner I 
Element type 
Fuel 
Specification l 
l Wlth parking brake applied (Canada) 
‘2 TEN terminal of diagnosis connector grounded Oil permeated 
Unleaded regular (RON 91 or higher) 23UOFX-012 
F-l 5  

F OUTLINE 
COMPONENT DESCRIPTIONS 
Component 
Air cleaner 
Airflow meter 
Mr valve 
Atmospheric pressure 
Sensor 
Catalytic converter Function Remark 
Filters air entering throttle body 
Detects amount of intake air; sends signal to intake air thermosensor and fuel pump 
ECU switch included 
Supplies bypass air into dynamic chamber 
l Engine speed increased to shorten 
when engine is cold warm-up period 
l Thermowax type l Installed in dynamic chamber 
Detects atmospheric pressure; sends signal Built in ECU 
to ECU 
Reduces HC, CO, and NOx by chemical Monolith type 
reaction Charcoal canister 
Stores fuel tank fumes while engine stopped Check valve 
Controls pressure in fuel tank Two-way type Circuit opening relay 
Voltage for fuel pump while engine running Clutch switch (MTX) 
Detects clutch condition; sends signal to Switch OFF when clutch pedal released 
ECU Diagnosis connector 
Concentrated service connector 25pin (located near left suspension mount- 
Concentrated terminals: ing block) 
1. EGI self-diagnostic terminal 
2. EC-AT self-diagnostic terminal 
3. Test terminal 
4. Fuel pump check terminal 
5. Cooling fan check terminal 
6. Engine rpm output terminal Dynamic chamber 
Interconnects all cylinders Engine control unit (ECU) Detects the following: 
1. A/C operation 1. A/C switch 
2. Air/fuel ratio (Oxygen concentration) 2. Oxygen sensor 
3. ATF thermosensor 
4. Atmospheric pressure 4. Atmospheric pressure sensor 
5. Braking signal 5. Stoplight switch (MTX) 
6. Cranking signal 6. Ignition switch (START Position) 
7. DRL (Daytime Running Light) operation 7. DRL relay (Canada) 
8. E/L operation 8. Blower motor switch, cooling fan relay, 
headlight switch, and rear window 
defroster switch 
9. Engine coolant temperature 9. Water thermosensor 
10. Engine speed 10. Distributor (Ne-signal) 
11. Ignition ON signal 11. Ignition switch 
12. In-gear condition 12. Neutral and clutch switches (MTX) 
13. Inhibitor switch (ATX) 13. N range, D range, S range, L range 
switch 
14. Intake air amount 14. Airflow meter 
15. Intake air temperature 15. Intake air thermosensor 
(In airflow meter) 
16. No.1 piston TDC of compression 
17. P/S operation 
18. Shift solenoid (ATX) 
19. Test signal (Ignition timing, idle speed, 
Malfunction code No.) 
20. Throttle valve fully closed/fully open 
condition 16. Distributor (G-signal) DOHC) 
17. P/S pressure switch 
18. 1-2, 2-3, 3-4, Lockup solenoid 
19. Diagnosis connector 
(TEN terminal) 
20. Throttle sensor (MTX) 
21. Throttle valve opening angle 
22. Turbine sensor 21. Throttle sensor (ATX) .__r 
F-10  

OUTLINE 
Component Function Remark 
Engine control unit (ECU) Controls operation of the following: 
(Cont’d) 
1. A/C (Cut-off) 1. A/C relay 
2. Fail-safe function 2. Self-Diagnosis Checker and MIL 
3. Fuel injection system 3. Injector 
4. idle speed control 4. Idle speed control (ISC) valve 
5. Ignition timing control system 5. Igniter 
6. Monitor function 6. Monitor lamp (Self-Diagnosis Checker) 
7. Pressure regulator control system 7. Solenoid valve 
(Pressure regulator control) (BP) 
8. Purge control system 8. Purge control solenoid valve 
9. VICS 9. Solenoid valve (WCS) (DOHC) Fuel filter 
Filters particles from fuel Fuel pump 
Provides fuel to injectors l Operates while engine running l Installed in fuel tank Igniter 
Receives spark signal from ECU and gener- 
ates high voltage in ignition coil Ignition switch 
Engine cranking signal sent to ECU (START position) 
Inhibitor switch (ATX) 
Detects in-gear condition; sends signal to Switch ON in N or P range 
ECU Injector 
Intake air thermosensor 
Idle speed control (ISC) 
valve 
Main relay 
(FUEL INJ relay) 
MIL (Malfunction 
indicator lamp) 
Neutral switch (MTX) 
Oxygen sensor 
PCV valve 
P/S pressure switch 
Pressure regulator 
Resonance chamber 
Resonance duct 
Separator 
Stoplight switch 
Solenoid valve 
(Purge control) 
Shutter valve actuator 
(DOHC) 
Throttle body 
Throttle sensor 
Injects fuel into intake port l Controlled by signals from ECU 
l High-ohmic injector 
Detects intake air temperature; sends signal Installed on dynamic chamber 
to ECU 
Controls bypass air amount Controlled by duty signal from ECU 
Supplies electric current to injectors, ECU, 
etc. 
Lamp flashes to indicate malfunction code 
number of input and output devices 
Detects in-gear condition; sends signal to 
ECU 
Detects oxygen concentration; sends signal 
to ECU 
Controls blowby gas introduced into engine 
Detects P/S operation; sends signal to ECU 
Adjusts fuel pressure supplied to injectors 
Reduces intake air noise 
Reduces intake air noise 
Prevents fuel from flowing into charcoal 
canister 
Detects braking operation (deceleration), 
sends signal to ECU 
Controls evaporative fumes from canister to 
intake manifold 
Closes/opens shutter valve to improve 
torque characteristics 
Controls intake air quantity 
l Detects throttle valve fully closed/fully 
opened condition (MTX) TEN terminal grounded 
Switch ON in neutral 
Zirconia ceramic and platinum coating 
P/S: ON when steering wheel turned right or 
left 
Controlled by duty signal from ECU 
For Variable inertia charging system (VICS*) 
Integrated throttle sensor, dashpot, and ISC 
valve 
l Detects throttle valve opening angle 
(A-W 
l Sends signals to ECU 
F-l 7  

TROUBLESHOOTING GUIDE F 
REAR SEAT C 
03UOFX-01 
9MUOF2-1; 
PRECAUTION 
Fuel Pressure Release and Servicing Fuel System 
Fuel in the fuel system remains under high pressure even when 
the engine is not running. 
a) Before disconnecting any fuel line, release the fuel pres- 
sure from the fuel system to reduce the possibility of injury 
or fire. 
1. Start the engine. 
2. Push the rear seat cushion buttons and remove the 
cushion. 
3. Disconnect the fuel pump connector. 
4. After the engine stalls, turn off the ignition switch. 
5. Reconnect fuel pump connector and install the rear seat 
cushion. 
b) Use a rag as protection from fuel spray when disconnect- 
ing the hoses. 
Plug the hoses after removal. 
c) When inspecting the fuel system, use a suitable fuel pres- 
sure gauge. 
Caution 
l Install hose clamps to secure the fuel pressure 
gauge to the fuel filter and the fuel main hose to pre- 
vent fuel leakage. 
Pinching Hose 
When pinching an air hose or a fuel hose with pliers, wrap 
the hose with a rag to prevent damage. 
03UOFX-016 
F-29  

F TROUBLESHOOTING GUIDE 
TEP INSPECTION ACTION 
6 Check if throttle linkage is correctly installed and Yes Go to next step 
operates freely 
w page F-l 14 
No Correct, clean, or replace as required 
any binding or damaged linkage, and 
adjust cable deflection at throttle body CT page F-l 12 
7 Check for correct intake manifold vacuum at idle Yes Go to next step 
Vacuum: More than 450 mmHg (17.7 intig) - 
No 
Check for air leakage of intake air sys- 
tem components 
8 Check if air cleaner element is clean Yes Go to next step 
w page F-79 
No Replace air cleaner element 
9 Connect System Selector to diagnosis connector Yes Check if ignition timing advances when 
and set Test Switch to “SELF TEST” and check accelerating 
for correct ignition timing at idle after warm-up 
w page F-79 c3 If advances, go to next step 
c3 If not advance, replace ECU [II page F-149 
Ignition timing (BTDC) 
l BP DOHC : Q”-1 1 o l BP SOHC : 4O-6’ 
’ B6 : 6O-8O 
No Adjust CT+ page F-79 
10 Check for correct fuel line pressure at idle Yes Check if fuel line pressure decreases 
w page F-129 when accelerating quickly 
Fuel line pressure: c3 If decreases, check for fuel pump 
265-314 kPa (2.7-3.2 kg/cm*, 38-46 psi) maximum pressure w page F-126 
(Vacuum hose to pressure regulator dis- If OK, check fuel line and filter for 
connected) clogging CI,’ page F-122 
+ If no decrease, go to next step 
- 
No Low pressure 
Check fuel line pressure by pinching 
fuel return hose 
cti If fuel line pressure quickly In- 
creases, check pressure regulator CT page F-129 
ti If fuel line pressure gradually in- 
creases, check for clogging be- 
tween fuel pump and pressure 
regulator 
If not clogged, check fuel pump 
maximum pressure cr page F-126 
- 
High pressure 
Check if fuel return line is clogged 
Q If OK, replace pressure regulator C-Y- page F-130 
+ If not OK, replace 
--_I. 1”1-~~-~~ 
11 Check if exhaust system is restricted Yes Repair or replace 
C-T- page F-136 
No Go to next step 
12 Try known good ECU and check if condition 
improves 
CT page F-149 
23UOFX-034 
F-60  

F TROUBLESHOOTING GUIDE 
ITEP 
INSPECTION ACTION 
6 Check for correct intake manifold vacuum at idle Yes Go to next step 
Intake manifold vacuum: 
More than 450 mmHg (17.7 inHg) No Check for air leakage of intake air sys- 
tem components 
7 Check if air cleaner element is clean Yes Go to next step 
w page F-79 
No Replace air cleaner element 
8 Check for correct fuel line pressure at idle Yes Check if fuel line pressure decreases 
CT= page F-129 when accelerating quickly 
Fuel line pressure: c3 If decreases, check fuel pump 
265-314 kPa (2.7-3.2 kg/cm’, 38-46 psi) maximum pressure w page F-126 
(Vacuum hose to pressure regulator dis- If OK, check fuel line and filter for 
connected) clogging 
ti If not decrease, go to next step 
No Low pressure 
INSTALL CLAMPS Check fuel line pressure while pinching 
fuel return hose 
9 If fuel line pressure quickly in- 
creases, check pressure regulator w page F-129 
c3 If fuel line pressure gradually in- 
creases, check for clogging be- 
tween fuel pump and pressure 
regulator 
If not clogged, check fuel pump 
maximum pressure w page F-126 
High pressure 
Check if fuel return line is clogged 
c3 If OK, replace pressure regulator CT page F-130 
d If not OK, replace 
9 Check if airflow meter is OK 
Yes Go to next step 
w page F-188 
I. Check if measurin late moves smoothly 
II. Check resistance No Repair or replace 
F-62  

iTEP INSPECTION ACTION 
5 Connect System Selector to diagnosis connector Yes 
and set Test Switch to “SELF TEST” and check Check if ignition timing advances when 
for correct ignition timing at idle after warm-up accelerating w page F-79 
* If advances, go to next step 
r3 If not advance, check ECU terminal Ignition timing (BTDC) 
voltages l BP DOHC : go--ll” w page F-150 l BP SOHC : 4O-6O 
. B6 : 6O-6O 
No 
Adjust w page F-79 
6 
Check if ECU terminal voltages are OK 
Yes Go to next step w page F-150 
No 
Check for cause ~7 page F-151 
7 
Check for correct intake manifold vacuum at idle 
Yes Go to next step Intake manifold vacuum: 
More than 450 mmHg (17.7 inHg) No 
Check for air leakage of intake air sys- 
tem components 
8 Check for correct fuel line pressure at idle 
Yes Check if fuel line pressure decreases w page F-129 
when accelerating quickly Fuel line pressure: 
265-314 kPa (2.7-3.2 kg/cm’, 39-46 psi) 
(Vacuum hose to pressure regulator dls- 
connected) 
d If decreases, check fuel pump 
maximum pressure (3‘ page F-126 
If OK, check fuel line and filter for 
clogging 
* If not decrease, go to next step 
No Low pressure 
Check for fuel line pressure while pinch- 
ing fuel return hose 
c3 If fuel line pressure quickly in- 
creases, check pressure regulator w page F-129 
+ If fuel line pressure gradually in- 
creases, check for clogging be- 
tween fuel pump and pressure 
regulator 
If not clogged, check fuel pump 
maximum pressure w page F-126 
High pressure 
Check if fuel line is clogged 
* If OK, replace pressure regulator w page F-130 
c3 If not OK, replace 
F-66  

FUEL PUMP CONNECTOR 
/ 
REAR SEAT C 
FUEL SYSTEM F 
PRECAUTION 
Fuel Pressure Release and Servicing Fuel System 
Fuel in the fuel system remains under high pressure even when 
the engine is not running. 
a) Before disconnecting any fuel line, release the fuel pres- 
sure from the fuel system to reduce the possibility of injury 
or fire. 
1. Start the engine. 
2. Push the rear seat cushion buttons and remove the 
cushion. 
3. Disconnect the fuel pump connector. 
4. After the engine stalls, turn off the ignition switch. 
5. Reconnect the fuel pump connector and install the rear 
seat cushion. 
b) Use a rag as protection from fuel spray when disconnect- 
ing the hoses. 
Plug the hoses after removal. 
c) When inspecting the fuel system, use a suitable fuel pres- 
sure gauge. 
Caution 
l Install hose clamps to secure the fuel pressure 
gauge to the fuel filter and the fuel main hose to pre- 
vent fuel leakage. 
9MUOF2-122  OBUOFX-126 
DlAGNOS&O,NNECTOR 
03UOFX-12. 
- 
DISCONNECT CONNECTOR 
/ TO RELEASE FUEL PRESSURE 
03UOFX-12; 
Priming Fuel System 
After releasing the fuel pressure for repairs or inspection, the 
system must be primed to avoid excessive cranking when first 
starting the engine. Follow the steps below. 
1. Connect the diagnosis connector terminals 
F/P and GND 
with a jumper wire. 
2. Turn the ignition switch 
ON for approx. 10 sec. and check 
for fuel leaks. 
3. Turn the ignition switch OFF and remove the jumper wire. 
SYSTEM OPERATION 
Fuel Pressure Hold Inspection 
Warning 
l Before performing the following operation, release 
the fuel pressure from the fuel system to reduce the 
possibility of injury or fire. (Refer to above.) 
F-121