ECU TOYOTA CELICA 1987 Service Repair Manual

IN-4 Identification Information,
INTRODUCTION - General Repair Instructions
IDENTIFICATION INFORMATION
ENGINE SERIAL NUMBER
The engine serial number is stamped on the right side of the
cylinder block.
Seal Lock Adhesive
GENERAL REPAIR INSTRUCTIONS
1. Use fender, seat and floor covers to keep the vehicle clean
and prevent damage.
2.
3. During disassembly, keep parts in order to facilitate
reassembly.
Observe the following:
(a)
(b) Before performing electrical work, disconnect ‘the
negative (-1 cable from the battery terminal.
If it is necessary to disconnect the battery for inspec-
tion or repair, always disconnect the cable from the
negative (-) terminal which is grounded to the vehi-
cle body.
(c) To prevent damage to the battery terminal post,
loosen the terminal nut and raise the cable straight up
without twisting or prying it.
(d) Clean the battery terminal posts and cable terminals
with a shop rag. Do not scrape them with a file or
other abrasive object.
(e)
(f) Install the cable terminal to the battery post with the
nut loose, and tighten the nut after installation. Do
not use a hammer to tap the terminal onto the post.
Be sure the cover for the positive (+I terminal is pro-
perly in place.
4.
5. Check hose and wiring connectors to make sure that they
are secure and correct.
Non-reusable parts
(a)’ Always replace cotter pins gaskets, O-rings, oil seals,
etc. with new ones.
(b) Non-reusable parts are indicated in the component
illustrations by the “+” symbol.
6. Precoated Parts
Precoated parts are the bolts, nuts, etc. which are coated
with a seal lock adhesive at the factory.
(a) If a precoated part is retightened, loosened or caused
to move in any way, it must be recoated with the
specified adhesive.

INTRODUCTION - General Repair Instructions
IN-S
(b) Recoating of Precoated Parts
(1) Clean off the old adhesive from the part’s
threads.
(2) Dry with compressed air.
(3) Apply the specified seal lock adhesive to the
part’s threads.
(c) Precoated parts are indicated in the component
illustrations by the “*” symbol.
7. When necessary, use a sealer or gaskets to prevent leaks.
8. Carefully observe all specifications for bolt torques.
Always use a torque wrench.
9. Use of special service tools (SST) and special service
materials (SSM) may be required, depending on the nature
of the repair. Be sure to use SST and SSM where specified
and follow the proper work procedure. A list of SST and
SSM can be found at the back of this manual.
10. When replacing fuses, be sure the new fuse is the correct
amperage. DO NOT exceed the fuse amp rating or use one
of a lower rating.
11. Care must be taken when jacking up and supporting the
vehicle. Be sure to lift and support the vehicle at the
proper locations.
(a) If the vehicle is to be jacked up only at the front or
rear end, be sure to block the wheels in order to
ensure safety.
(b) After the vehicle is jacked up, be sure to support it on
stands. It is extremely dangerous to do any work on
the vehicle raised on a jack alone, even for a small job
that can be finished quickly.
WRONG
CORRECT 12. Observe the following precautions to avoid damaging the
parts:
(a) Do not open the cover or the case of the ECU unless
absolutely necessary. (If the IC terminals are touched,
the IC may be destroyed by static electricity.)
(b) Be careful not to drop electrical components, such as
sensors or relays. If they are dropped on a hard floor,
they should be replaced and not reused.
(c) When disconnecting vacuum hoses, pull on the end
of the hose, not the middle.
(d) When separating electrical connectors, pull on the
connector itself, not the wires.

FI-1
i’.. ;
-EFI SYSTEM
i
‘x
. .
Page
SYSTEM DESCRIPTION
....................... Fl-i.&.
PRECAUTIONS
;;:“, F,-, ;a”“- .............................. . ....
INSPECTION PRECAUTIONS
FI-7 . ....................
TROUBLESHOOTING
.......................... FI-12
DIAGNOSIS SYSTEM
.................... .
.... FI-25
TROUBLESHOOTING WITH
VOLT/OHMMETER (MA)
.................... FI-34
m
.:
TROUBLESHOOTING WITH
VOLT/OHMMETER (MS)
.................... FI-57
FUEL SYSTEM
................................ FI-73,
Fuel Pump ..................................
FI-73
Cold Start Injector ...........................
Fl-80
Pressure Regulator
.......................... FI’i84 ..
Injectors
.............................. ..i ..
FI-86
AIR INDUCTION SYSTEM
..................... FI-96
Air Flow Meter (7M-GE)
..................... FI-96
Air Flow Meter (7M-GTE)
................... FI-98
Throttle Body
.............................. FI-102
Idle Speed Control (ISC) Valve
............... FI-108
ELECTRONIC CONTROL SYSTEM .............. FI-110
Location of Electronic Control Parts .......... FI-110
l EFI Main Relay
............................. Fl-112
. Circuit Opening Relay ....................... FI-113
Solenoid Resistor
........................... Fl-114
Cold Start Injector Time Switch ...............
FI-115
Water Temperature Sensor ..................
FI-116
Fuel Pump Relay and Resistor ............... FI-117
High Temperature Line Pressure -
Up System ............................... FIi119
High Altitude Compensation (HACK
System (7M-GTE)
........................ FI-121
Oxygen Sensor .............................
FI-122
Electronic Controlled Unit (ECU) .............
FI-125
Fuel Cut RPM
.............................. FI-128

Circuit
Opening
Fuel Pump Relay
I
Warning 1
I :..I-, -7-I ECU
P 1
L-
VSV (FPU)
Electronic
Load
di!=
Check C&tnector
A/C Compressc
I-=-
Szeed Sensor
IIIII:IIlI Igniter w/coil
l---it-
Start‘lnjector Time Switch
Water Te&p. Sensor
TWC
Neutral Start
Switch (A/T)

Circuit
Opening
Relay Fuel Pump Relay
“CHECK 1 f-- 1 ] : :
llll II :
: :
ENGINE”
Warning
Light ECU
I iIll
+-,llllllllllll
Electronic
Load Air Temp. Sensor
Check Connector 1 1 1 / 1 1 1 1 1 1 1 1
:uator
Igniter w/r-:’ ’
A/C Compressor
& 1 wTwy 1 To Charcoal Canister
Neutral Start
Switch (A/T)

1-6 EFI SYSTEM - System Description
‘he .EFI system is composed of 3 basic sub
;ystems; Fuel Induction, Air Induction and
Ziectronic Control.
FUEL SYSTEM
An electric fuel pump supplies sufficient fuel,
under a constant pressure, to the injectors. These
injectors inject a metered quantity of fuel into the
intake manifold in accordance with signals from
the ECU (Electronic Control Unit).
AIR INDUCTION SYSTEM
The air induction system provides sufficient air for
engine operation.
[3: ‘I
i&TRONIC CONTROL SYSTEM
The 7M-GE, 7M-GTE engines are equipped wifh a
Toyota Computer Control System (TCCS) which
centrally controls the EFI, ESA, Diagnosis systems,
etc. by means of an Electronic Control Unit (ECU -
for-merly EFI computer) employing a microcom-
puter.
By means of the ECU, the TCCS controls the
following functions:
1. Electronic Fuel injection (EFI)
The ECU receivers signals from,various sen-
sors indicating changing engine operating
conditions such as:
Exhaust oxygen content (w/ TWC)
Intake air volume
i Intake air temperature
Coolant temperature
Engine rpm
Vehicle speed
Acceleration/deceleration etc.
These signals are utilized by the ECU to
determine the injection duration necessary for
an optimum air-fuel ratio.
2. Electronic Spark Advance (ESA)
The ECU is programmed with data for
optimum ignition timing under any and all
operating conditions. Using data provided by
sensors which monitor various engine func-
tions (rpm, A/C signal, coolant temperature,
etc.), the microcomputer (ECU) triggers the
spark at precisely the right instant. (See IG
section) 3. Idle Speed Control (IX)
The ECU is programmed with, target idling
speed values to respond to different engine
conditions (coolant temperature, air condi-
tioner on/off, etc.). Sensors transmit signals
to the ECU which control the flow of air
through the bypass of the throttle valve and
adjust idle speed to the target value.
(See pages FI-53, 7 1, 108) ’
4. Diagnosis
The ECU detects any malfunctions or abnor-
malities in the sensor network and tights the
“CHECK ENGINE” warning light on the instru-
ment panel. At the same time, the trouble is
identified and a diagnostic code is recorded
by the ECU.
5. Fail-Safe Function ’
In the event of computer malfunction, a back-
up circuit will take over to provide minimal
drivability. Simultaneously, the “CHECK
ENGINE” warning light will come on.

EFI SYSTEM
- Precautions, Inspection Precautions
FI-7
PRECAUTIONS
._
1. Before working on the fuel system, disconnect the
negative terminal from the battery.
NOTE: Any diagnosis code retained by the computer will
be erased when the battery terminal is removed.
Therefore, if necessary, read the diagnosis before
removimg the battery terminal.
2. Do not smoke or work near an open flame when work-
ing on the fuel system.
3. Keep gasoline off rubber or leather parts.
INSPECTION PRECAUTl.ONS
MAINTENANCE PRECAUTIONS
1. INSURE CORRECT ENGINE TUNE-UP
2. PRECAUTIONS WHEN CONNECTING GAUGE
(a) Connect the tachometer test probe to the terminal
IGO of check connector.
CHECK CONNECTOR LOCATION:
See pages FI-110, 111
(b) Use the battery as the power source for the timing
light, tachometer, etc.
3. IN EVENT OF ENGINE MISFIRE FOLLOWING
PRECAUTIONS SHOULD BE TAKEN
(a) Insure proper connection of battery terminals, etc.
(b) Handle high tension cords carefully.
(c) After repair work, insure that the ignition coil ter-
minals and all other ignition system lines are recon-
nected securely.
(d) When cleaning the engine compartment, be especial-
ly careful to protect the electrical system from water.
4. PRECAUTIONS WHEN HANDLING OXYGEN SENSOR
(w/ TWCI
(a) Do not allow oxygen sensor to drop or hit against an
object.
(b) Do not allow water to come into contact with the
sensor or attempt to cool it.

-8 EFI SYSTEM -.- Inspection Precautions
IF VEHICLE IS EQUIPPED WITH MOBILE
RADIO SYSTEM (HAM, CB, ETC)
The ECU has been designed so that it will not be affected by
outside interference.
However, if your vehicle is equipped with a CB radio
transceiver, etc. (even one with about 10 W output), it may, at
times, have an affect upon ECU operation, especially if the
antenna and feeder are installed nearby.
Therefore, observe the following precautions:
1. Install the antenna as far as possible from the ECU. The
ECU is located behind the glove box (MA) or passenger’s
kick panel (MS), so the antenna should be installed in the
rear of the vehicle.
2. Keep the antenna feeder as far .away as possible from the
ECU wires at least 20 cm (7.87 in.), and especially, do not
wind them together.
3. Insure that the feeder and antenna are properly adjusted.
4. Do not equip your vehicle with a powerful mobile radio
system.
Do not open the cover or the case of the ECU unless
absolutely necessary. (If the IC terminals are touched, the
. . .
IC may be destroyed by static electricity.1
AIR INDUCTION SYSTEM
1.
2. Separation the engine oil dipstick, oil filler cap, PCV hose,
etc., may cause the engine to run out of tune.
Disconnection, looseness or cracks in the parts of the air
induction system between the air flow meter and cylinder
head will allow air suction and cause the engine to run out
of tune.
TM-GE (MS)
7M-GTE

EFI SYSTEM - inspection Precautions
FI-9
FM066
FlOO95 FlOO91
ELECTRONIC CONTROL SYSTEM
1.
2.
3. Before removing EFI wiring connectors, terminals, etc.,
first disconnect-the power-by either turning the ignition
switch OFF or disconnecting the battery terminals.
When installing a battery, be especially careful not to
incorrectly connect the positive and negative cables.
Do not permit parts to receive a severe impact during
removal or installation. Handle all EEI parts carefully.
especially the ECU.
4. Do not be careless during troubleshooting as there are
numerous transistor circuits and even slight terminal con-
tact can cause further troubles.
5.
6. Do not open the ECU cover.
When inspecting during rainy weather, take care to pre-
vent entry of water. Also, when washing the engine com-
.partment, prevent water from getting on the EFI parts and
wiring connectors.
7. Parts should be replaced as an assembly.
8. Care is required when pulling out the inserting wiring con-
nectors.
(a) Release the lock and pull out the connector, pulling
on the connectors. .
(b) Fully insert the connector and insure that it is locked.
9. When inspecting a connector with a circuit tester.
(a) Carefully take out the water-proofing rubber if it is a
water-proof type connector.

FI-10 EFI SYSTEM - inspection Precautions
L Fco97 FlOO91
I
. FI159
i. 4 Gasket
New
‘Gasket
I / FM067 FHOE
Fulcrum Length
19
54
-.
(b) insert the tester probe into the connector from the
wiring side when-checking the continuity,,amperage
L
or voltage.
(c) Do not apply unnecessary force to the terminal.
(d) After checking, install the water-proofing rubber on
the connector securely.
10. Use SST for inspection or test of the injector, cold start
injector or its wiring connector.
SST 09842-30050 and 09842-30060
FUEL SYSTEM
1.
2. When disconnecting the high fuel pressure line, a large
amount of gasoline will spill out, so observe the following
procedure.
(a) Put a container under the connection.
(b) Slowly loosen the connection.
(c) Disconnect the connection.
(d) Plug the connection with a rubber plug.
When connecting the flare nut or union bolt on the high
pressure pipe union, observe the following procedure:
(Union bolt type)
(a) Always use a new gasket.
(b) Hand tighten the union bolt.
(c) Tighten the bolt to the specified torque.
Torque: 300 kg-cm (22 it-lb, 29 N*m)
(Flare nut type)
(a) Apply a thin coat of oil to the flare and tighten the
flare nut.
(b) Then using SST, tighten the nut to the specified tor-
que.
SST 09631-22020
Torque: 310 kg-cm (22 ft-lb, 30 N*m)
NOTE: Use a torque wrench with a fulcrum length of 30
cm (11.81 in.).