coolant temperature TOYOTA CELICA 1987 Service Repair Manual

. COOLING SYSTEM - Description
co;3
RESERVOIR TANK
The reservoir tank is used to catch coolant
which overflows the cooling systein as a result of
volumetric expansion when the coolant is heated.
The coolant in the reservoir tank returns to the
radiator when the coolant temperature drops, thus
keeping the radiator full at all times and avoiding
needless coolant loss. Check the reservoir tank
level to learn if the coolant needs to be rep-
lenished.
WATER PUMP
The water pump is used for forced circulation of
coolant through the cooling system. It is mounted
on the front of the cylinder block and driven by a
V-ribbed belt,
THERMOSTAT I The cooling system is composed of the water
jacket (inside the cylinder block and cylinder head),
radiator, water pump, thermostat, cooling fan,
hoses and other components.
Coolant which is heated in the water
jacket is
pumped to the radiator, through which a cooling
fan blows air to cool the coolant as it passes
through. Coolant which has been cooled is then
sent back to the engine by the water pump, where
it cools the engine.
The water jacket is a network of channels in the
shell of the cylinder block and cylinder head
through which coolant passes. It is designed to
provide adequate cooling of the cylinders are com-
bustion chambers which become the hottest dur-
ing engine operation.
F(/ “ IATOR
The radiator performs the function of cooling
the coolant which has passed through the water
jacket and become hot, and is mounted in the front
of the vehicle. The radiator consists of an upper
tank and ‘lower tank, and a core which connects
the two tanks. The upper tank contains the inlet for
coolant from the water jacket and the filter inlet. It
also has a hose attached through which excess
coolant or steam can flow. The lower tank contains
the outlet for coolant and the drain cock. The core
contains many tubes through which coolant flows
from the upper tank to the lower tank as well as
cooling fins which radiate heat away from the coo-
lant in the tubes. The air sucked through the radia-
tor by cooling fan, as well as the wind generated
by the vehicle’s travel, passes through the radia-
tor, cooling it. Models with automatic transmission
incrl*-le an automatic transmission fluid cooler built
in:.
.le lower tank of the radiator.
RADIATOR CAP
The radiator cap is a pressure type can which
seals the radiator, resulting in pressurization of the
radiator as the coolant expands. The pressuriza-
tion prevents the coolant from boiling even when
the coolant temperature exceeds 100°C. A relief
valve (pressurization valve) and a vacuum valve
(negative pressure valve) are built into the radiator
zap. The relief valve opens and lets steam escape
:hrough the overflow pipe when the pressure
3enerated inside the cooling system exceeds the
imit (coolant temperature:
110 - 1 20°C, (230
- 248”F), pressure; 0.3 - 1 .O kg/cmz, (4.3 - 14.2
)si, 29.4 - 98.1 kPa). The vacuum valve opens to
3ljeviate the vacuum which develops in the coolant
system after the engine is stopped and the coolant
emperature drops. The valve’s opening allows the
)ressure in the cooling system to return to the
Qclant in the reservoir tank. The thermostat has a wax type and is mounted
in the. water outlet housing. The thermostat
includes a type of automatic valve operated by
fluctuations in the coolant temperature. This valve
closes when the coolant temperature drops, pre-
venting the circulation of coolant through the
engine and thus permitting the engine to warm up
rapidly. The valve opens when the coolant tem-
perature has risen, allowing the circulation of coo-
lant. Wax inside the thermostat expands when
heated and contracts when cooled. Heating the
wax thus generates pressure which overpowers
the force of the spring which keeps the valve
closed, thus opening the valve. When the wax
cools, its contraction causes the force of the
spring to take effect once more, closing the valve.
The thermostat in this engine operates at a tem-
perature of 88”C(19O”F).
I
I

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 - Troubleshooting with’ Volt/Ohmmeter (MA) FI-37
Voltage at EClJ Wiring .Connectors (TIM-GE)
IO. Terminals
Condition STD Voltage
See page
BATT - El
10 - 14 FI-39
IG S/W - El
1 FI-40
M-REL - El
Ignition S/W ON 10 - 14
+B (+Bl) - El FI-41
IDL - E2 Throttle valve open 10 - 14 FI-42
vc - E2 -
4-6
2 Ignition S/W ON -
Throttle valve fully ‘closed 0.1
- 1.0 FI-43
VTA - E2
Throttle valve fully open 4-5
VC - E2 4-6
Ignition S/W ON
Measuring plate fully closed 4-5
3 Measuring plate fully open 0.02 - 0.08 FI-44
VS - E2
Idling 2-4
3,000 rpm 0.3 - 1.0
No. 10 EOI
5 No. 20 - Ignition S/W ON 9 - 14 FI-47
No. 30 E02
6 THA - E2 Ignition S/W ON Intake air temperature 20°C (68°F) 1 -3 FI-48
7 THW - E2 Ignition S/W ON Coolant temperature 80°C II 76’F) 0.1 - 1 .O
FI-49
8 STA - El Cranking
6 - 14 FI-50
9 IGF, IGT - El Idling
0.7 - 1.0 FI-5 1
11 ISCI
I&4 - El Ignition S/W ON 9-14 Fl-53
12 W - El No trouble (“CHECK ENGINE” warning light off) and
engine running 8 - 14 FI-54
13 A/C - El Air conditioning ON IO - 14 FI-55
ECU Terminals
‘~,~] E2 4
/UC W:G up +S :,:I
N:y Is’ Is’ GO Gl G2 NE IGT IGF THW OX “s, “;“riL EGR SPD FPR THA VS VC BATT IG
F1057

EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MA)
. .
Voltage at ECU Wiring Connectors (7M-GTE)
No. Terminals
Condition STD Voltage Sea page
BATT - El 10 - 14
FI-39
IG S/W - El
1
FI-40
M-REL - El Ignition S/W ON 10 - 14
+B (+Bl) - El
FI-41
*
IDL - E2 Throttle valve open 10 - 14 FI-42
VC - E2 4-6.
2 . Ignition S/W ON
Throttle valve fully closed 0.1 - 1.0 FI-43
VTA - E2
Throttle valve fully open 4-5
i
KS - Body Ignition S/W ON 4-6
FI-45
gnMid
4 Cranking or running 2-4
vc - Body
Ignition S/W ON 4-6
groulld Fl-46.
No. 10 EOl
5 No. 20 - Ignition S;W CN 9 - 14 Fl-47
No. 30 E02
6 THA - E2 Ignition S/W ON Intake air temperature 20°C (68°F) 1 -3 FI-48
7 THW - E2 Ignition S/W ON Coolant temperature 80°C (176°F) 0.1 - 1 .O FI-49
8 STA - El Cranking 6-14 FI-50
9 IGF, IGT - El Idling 0.7 - 1.0 FI-5 1
10 IGdA, IGdB - El Idling 1-3 FI-52
11 I Cl
7 9 - 14 FI-53
ISC4 - El Ignition S/W ON
12 W - El No trouble (“CHECK ENGINE” warning light off) and
engine running 8 - 14 FI-54
13 A/C - El
14 HAC - E2 Air conditioning ON 10 - 14
FI-55
540 mmHg (21.26 in.Hg. 72.0 kPa) Approx. 2.8
Ignition S/W ON FI-56
750 mmHg (29.53 in.Hg, 100.0 kPa) Approx. 3.6
ECU Terminals
I U 1 I -
I
1
‘yc ‘;c GQ Gl G2 NE IGT IGF ~Hln, OX “;’ HT r;,
EGR SPD FPR THA HAC VC ‘JAn& 0 DF
‘;’ ‘sd: VF T VTA IDL
WA ““1” K;K E2 Ll L2 L3 NC W OIL ECT FC KS +B +Bl m
TIL LP

EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MA) Fl-49
-.
No.
Terminals Trouble
Condition
STD Voltage
7 THW - E2 No voltage ignition switch
Coolant temperature 80°C
ON (1780~) o-q - l-0 V
ECU
Water Temp. Sensor
. iB (+Bll
THW
E2
El
Jf /
Voltmeter
n F1031:
1
0 There is no voltage between ECU terminals THW and E2.
(IO S/W ON)
1 i
CD Check that there is voltage between ECU terminal +B (+Bl) and
body ground. (IG S/W ON)
1
OK
NO
Refer to No. 1.
(See page FI-41)
Check wiring between ECU terminal El and body ground.
OK
, 1
0 Check water temp. sensor.
(See page FI-1 161
I I
Try another ECU. OK
Check wiring between ECU and water
temp. sensor.
OK BAD
Repair or replace.

EFI SYSTEM - Ttpbleshooting with Volt/Ohmmeter (MS)
FL59
IO.
I Terminals
BATT - El
IG S/W - El
M-REL - El
2P-
I UTA - E2
3
US - E2
THA - E2
THW - E2
.B / IGF, IGT - El
9 ISCI
lSC4 - El
10
I W - El
ECU Terminals
Voltage at ECU Wiring Connectors
Condition STD Voltage ’
10 - 14
ignition S/W ON
10 - 14
Throttle valve open 10 - 14
4-6
Ignition S/W ON .
Throttle valve fully closed 0.1 - 1.0
Throttle valve fully open
4-5
4-6
Ignition S/W ON Measuring plate fully closed
4-5
Measuring plate fully open
0.02 - 0.08
Idling 2-4
3,000 rpm 0.3 - 1 .o
Ignition S/W ON 9
- 14 FI-66
Ignition S/W ON Intake air temperature 20°C (68°F) 1
-3
Ignition S/W ON
Coolant temperature 80°C (176°F) 0.1 - 1.0
Cranking
6 - 14
Idling 0.7 - 1.0
Ignition S/W ON
9 - 14
No trouble (“CHECK-ENGINE” warning light off) and
engine running 8 - 14 See page
FI-60
FI-6 1
FI-62
FI-63
FI-64
Fl-65
Fl-6.7
FI-68
FI-69
Fl-70
FI-7 1
Fl;72

EFI SYSTEM
- Troubleshooting with Voltkhmmeter (MS)
-.
No. 1
Terminals
I Trouble
I Condition ._
I STD Voltage
6 THW - E2 .No voltage Ignition switch Coolant temperature 80°C
ON (, 760F) 0.1 - 1.0 v
Water Temp. Sensor
. ECU
5 031)
THW
E2
:1
ECU I terminals THW and E2.
I
0 There is no voltage between ECU
(IG S/W ON)
I-
:.
0 Check that there is voltage between ECU terminal B (61) and
body ground. (IG S/W ON) -
1
OK NO
I
I 8 1
I
Refer to No. 1.
(See page FL62)
I
I I . -
I
Check wiring between ECU terminal El and body ground.
I BAD
Check water temp. sensor.
Repair or replace.
BAD
Replace water
temp. sensor. OK
Check wiring between ECU and water
I temp. sensor.
OK BAD
Try another ECU. 1 Repair or replace. 1

I ECU
ul +B +B
r
MS
ECU
Electronic Controlled Unit (ECU)
._
INSPECTION OF ECU
NOTE:
The EFI circuit can be checked by measuring the
resistance and voltage at the wiring connectors of the
ECU. .
1.
(MS)
PREPARATION
(See page FI-58)
2. INSPECT VOLTAGE OF ECU
Check the voltage between each terminal of the wiring
connectors.
0 Turn the ignition switch ON.
0 Measure the voltage at each terminal.
NOTE:
0 Perform all voltage measurements with the connectors
connected.
0 Verify that the battery voltage is 11 V or more when the
ignition switch is ON.
Voltage at ECU Wiring Connectors
I I I Terminals STD Voltage t Condition
I
BATT - El
IG S/W - El
10 - 14
M-REL - El
Ignition S/W ON
.
IDL - E2
VC (VCC) -. E2
VIA - E2 4-6 Throttle valve open
4-6
Ignition S/W ON
0.1 - 1.0 Throttle valve fully closed
4-5 Throttle valve fully open
4-5
Measuring plate fully closed
Ignition S/W ON
0.02 - 0.08
“‘vs Measuring plate fully open
- E2
2-4 Idling
0.3 - 1 .o 3,000 rpm
4-6
*2KS Ignition S/W ON
- E2
2-4 Cranking or running
VC - E2-
THA - E2 4-6 Ignition S/W ON
1 -3 Ignition S/W ON Intake air temperature 20°C (68°F)
THW - E2 0.1 - 1.0 Ignition S/W ON Coolant temperature 80°C (I 76°F)

EFI SYSTEM - Electronic Control. System
FL127
ECU Wiring . .
3.
INSPECT RESISTANCE OF ECU
CAUTION: .-
l Do not touch the ECU terminals.
0 The tester probe should be inserted into the wiring
connector from the wiring side.
Check the resistance between each terminal of the wiring
connectors.
l Disconnect the wiring connectors from the ECU.
0 Measure th.e resistance each terminal.
I
Resistance of ECU Wiring Connectors
Terminals Condition
. I Resistance Ifi)
I
IDL : E2
VTA - E2
VC WCC) - E2 Throttle valve open
Throttle valve fully closed
Throttle valve fully open
Throttle valve fully closed cc
Less than 2,300
3,500 - 10,300
300 - 6,300
200 - 400
*‘VS - E2 Measuring plate fully closed
Measuring plate fully open 20 - 600
20 - 1,200
I *2KS -E2 co I I I
“2E2 +KS -
5,000 - 10,000 I
I
“2VC -E2
10,000 - 15,000
I “2E2 -+VC
I I 5,000 - 10,000 I
THA - E2
THW - E2
Gl,G2 - GO
NE-GO Intake air temperature 20°C (68’FI
. Coolant temperature 80°C (176°F) 2,000 - 3,000
200 - 400
140 - 180
Iscl, I%2 _ +a (8)
ISC3, ISC4 10-30
+2 HAC - E2 2,900 - 4,200
*I 7M-GE only
*2 7M-GTE only

ENGINE MECHANICAL -, Description
EM-3
The 7M-GE, 7M-GTE engines are an in-line 6-
cylinder engine with the cylinders numbered l-2-
3-4-5-6 from the front. The crankshaft is sup-
ported by 7 bearings specified by the inside of the
crankcase. These bearings are made of kelmet.
.The crankshaft is integrated with 8 weights
which are cast along with it for balancing. Oil holes
‘are built into the crankshaft for supplying oil to the
connecting rods, pistons and other components.
These engine’s ignition order is l-5-3-6-2-4 .
The cylinder head is made of aluminum alloy, with
a cross flow type intake and exhaust layout and
with pent roof type combustion chambers. The
spark plugs are located in the center of the com-
bustion chambers.
Exhaust and intake valves are equipped with
irregular pitch springs with symmetrical ends
made of oil tempered silicon chrome steel wire
which are capable of following the valves even at
,high engine speeds.
Both the exhaust side cam shaft and the. intake
side cam shaft are driven by a single timing belt.
The cam journal is supported at 7 places between
the valve lifters of each cylinder and on the
cylinder head of front end. Lubrication of the cam
journal and cam is accomplished by oil being sup-
plied through the oiler port in the center of the
camshaft.
Adjustment of the valve clearance is done by
means of an outer shim type system, in which
valve adjusting shims are located above the valve
lifters. This permits replacement of the shims
without removal of the camshafts.
The resin timing belt cover is made in 2 pieces.
Pistons are made of highly temperature-resis-
tant aluminum alloy, and depressions are built into
the piston head to prevent interference with
valves.
Piston pins are the full-floating type, with the
pins fastened to neither the piston boss nor the
connecting rods. Instead, snap rings are fitted on
both ends of the pins, preventing the pins from
falling out.
The No. 1 compression ring is made of stainless
steel and the No. 2 compression ring is made of
cast iron. The oil ring is made of a combination of
stainless steel. The outer diameter of each piston
ring is slightly larger than the diameter of the
piston
and the flexibility of the rings allows them
to hug the cylinder walls when they are mounted
on the piston. Compression rings No. 1 and No. 2
work to prevent the leakage of gas from the
cylinder and the oil ring works to scrape oil off the
cylinder walls to prevent it from entering the com-
bustion chamber.
The cylinder block is made of cast iron. It has 6
cylinders which are approximately 1.6 times the
length of the piston stroke. The top of the cylin- ders is closed off by the cylinder head and the
lower end of the cylinders becomes the crankcase,
in which the crankshaft is installed. In addition,- the
cylinder block contains a water jacket, through
which coolant is pumped to cool the cylinders.
The .oil pan is bolted onto the botiom of the
cylinder block. The oil pan is an oil reservoir made .
of pressed steel sheet. A dividing plate’is included
-inside the oil pan to keep sufficient oil in the bot-
tom of the pan even when the vehicle is tilted. This
dividing plate also prevent5 the oil from making
waves when the vehicle is stopped suddenly and
thus shifting the oil away from the oil pump suc-
tion pipe.