1986 TOYOTA SUPRA check engine

Troubleshooting
If the CO/HC concentration does not comply with regulations,
troubleshoot in the order given below.
(a) Check (main heated) oxygen sensors operation.
(See oxygen sensor(s) inspection in SFI System)
(b) See the table below for possible causes, and then inspect
and correct the applicable causes if necessary.
 CO HC Phenomenon Causes
 
 
 
 
 
 
 
 
Normal 
 
 
 
 
 
 
 
High 
 
 
 
 
 
 
 
Rough idle 
 
 
 
 
 
 
 
1. Faulty ignitions:

Incorrect timing

Fouled, shorted or improperly gapped plugs

Open or crossed high±tension cords (2JZ±GE)

Cracked distributor cap (2JZ±GE)
2. Incorrect valve clearance
3. Leaky EGR valve
4. Leaky intake and exhaust valves
5. Leaky cylinder
 
 
 
 
 
 
 
 
Low 
 
 
 
 
 
 
 
High 
 
 
 
 
 
 
 
Rough idle
(Fluctuating HC reading) 
 
 
 
 
 
 
 
1. Vacuum leaks:

PCV hose

EGR valve

Intake manifold

Air intake chamber

Throttle body

IAC valve

Brake booster line
2. Lean mixture causing misfire
 
 
 
 
 
 
 
 
 
 
High 
 
 
 
 
 
 
 
 
 
High 
 
 
 
 
 
 
 
 
 
Rough idle
(Black smoke from exhaust) 
 
 
 
 
 
 
 
 
 
1. Restricted air filter
2. Faulty SFI systems:

Faulty fuel pressure regulator

Clogged fuel return line

Defective ECT switch

Defective turbo pressure sensor (2JZ±GTE)

Faulty ECM

Faulty injector

Faulty throttle position sensor

Faulty VAF meter (2JZ±GE)

Faulty MAF meter (2JZ±GTE)
EG±8± ENGINEENGINE MECHANICAL

COMPRESSION CHECK
HINT: If there is lack of power, excessive oil consumption or
poor fuel economy, measure the compression pressure.
1. WARM UP AND STOP ENGINE
Allow the engine to warm up to normal operating tempera-
ture.
2. 2JZ±GE:
DISCONNECT DISTRIBUTOR CONNECTOR
3. 2JZ±GTE:
DISCONNECT CAMSHAFT POSITION SENSOR CON-
NECTORS
4. 2JZ±GE:
DISCONNECT HIGH±TENSION CORDS FROM SPARK
PLUGS
(See high±tension cords and cord clamps removal in
Ignition System)
5. 2JZ±GTE:
REMOVE IGNITION COILS ASSEMBLIES
(See ignition coils removal in Ignition System)
6. REMOVE SPARK PLUGS
7. CHECK CYLINDER COMPRESSION
(a) Insert a compression tester into the spark plug hole.
(b) Wh ile cra n kin g th e en g in e , me a su re th e co mp re ssio n
pressure.
HINT: Always use a fully charged battery to obtain engine rev-
olutions of 250 rpm or more.
(c) Repeat steps (a) through (b) for each cylinder.
NOTICE: This measurement must be done in as short a time as
possible.
Standard pressure:
2JZ±GE
1,275 kPa (13.0 kgf/cm
2, 185 psi) or more
2JZ±GTE
1,079 kPa (11.0 kgf/cm
2, 156 psi) or more
Minimum pressure:
2JZ±GE
1,079 kPa (11.0 kgf/cm
2, 156 psi)
2JZ±GTE
883 kPa (9.0 kgf/cm
2, 128 psi)
Difference between each cylinder:
98 kPa (1.0 kgf/cm
2, 14 psi) or less
(d) If the cylinder compression in 1 or more cylinders is low, pour
a small amount of engine oil into the cylinder through the
spark plug hole and repeat steps (a) through (b) for the
cylinder with low compression.
± ENGINEENGINE MECHANICALEG±9

VALVE CLEARANCE INSPECTION AND
ADJUSTMENT (2JZ±GE)
HINT: Inspect and adjust the valve clearance when the en-
gine is cold.
1. REMOVE THROTTLE BODY AND INTAKE AIR
CONNECTOR ASSEMBLY
(See steps 1 to 9 in injector removal in SFI System)
2. DISCONNECT HIGH±TENSION CORDS FROM
CYLINDER HEAD COVERS
(See high±tension cords and cord clamps removal in
Ignition System)
3. REMOVE NO.3, NO.1 AND NO.2 CYLINDER HEAD
COVERS
(a) Remove the 4 bolts, 4 nuts and No.3 cylinder head cover.
(b) Remove the 4 bolts, No.1 cylinder head cover and gasket.
(c) Remove the 4 bolts, No.2 cylinder head cover and gasket.
4. SET NO.1 CYLINDER TO TDC/COMPRESSION
(a) Turn the crankshaft pulley, and align its groove with timing
mark ºOº of the No.1 timing belt cover.
NOTICE: Always turn the crankshaft clockwise.
(b) Check that the timing marks of the camshaft timing pulleys
are aligned with the timing marks of the No.4 timing belt
cover.
If not, turn the crankshaft 1 revolution (360°).
5. INSPECT VALVE CLEARANCE
(a) Check only those valves indicated in the illustration.
wUsing a feeler gauge, measure the clearance between
the valve lifter and camshaft.
wRecord the valve clearance measurements of those that
are out of specification. They will be used later to
determine the required replacement adjusting shim.
± ENGINEENGINE MECHANICALEG±11

Valve clearance (Cold):
Intake
.15±0.25 mm (0.006±0.010 in.)
Exhaust
.25±0.35 mm (0.010±0.014 in.)
(b) Turn the crankshaft pulley 1 revolution (360°), and align the
groove with timing mark ºOº of the No.1 timing belt cover.
(c) Check only the valves indicated as shown. Measure the valve
clearance. (See procedure in step (a))
6. ADJUST VALVE CLEARANCE
(a) Remove the adjusting shim.
wTurn the camshaft so that the cam lobe for the valve to
be adjusted faces up.
wTurn the valve lifter with a screwdriver so that the
notches are perpendicular to the camshaft.
wUsing SST (A), hold the camshaft as shown in the
illustration.
SST 09248±55040 (09248±05410)
wUsing SST (A), press down the valve lifter and place
SST (B) between the camshaft and valve lifter. Remove
SST (A).
SST 09248±55040 (09248±05410, 09248±05420)
HINT:
wApply SST (B) at slight angle on the side marked with
º7º, at the position shown in the illustration. EG±12
± ENGINEENGINE MECHANICAL

wInsert SST (B) gently from the inside as shown in the
illustration.
wUsing a small screwdriver and a magnetic finger,
remove the adjusting shim.
(b) Determine the replacement adjusting shim size according to
the following Formula or Charts on the next 2 pages:
wUsing a micrometer, measure the thickness of the
removed shim.
wCalculate the thickness of a new shim so the valve
clearance comes within specified value.
T ......... Thickness of used shim
A ......... Measured valve clearance
N ......... Thickness of new shim
Intake
N = T + (A±0.20 mm (0.008 in.))
Exhaust
N = T + (A±0.30 mm (0.012 in.))
wSelect a new shim with a thickness as close as possible
to the calculated values.
HINT: Shims are available in 17 sizes in increments of 0.050
mm (0.0020 in.), from 2.500 mm (0.0984 in.) to 3.300 mm
(0.1299 in.).
(c) Install a new adjusting shim.
wPlace a new adjusting shim on the valve lifter, with
imprinted numbers facing down.
wPress down the valve lifter with SST (A), and remove
SST (B).
SST 09248±55040
(d) Recheck the valve clearance.
± ENGINEENGINE MECHANICALEG±13

3. CHECK IDLE SPEED
(a) Race the engine speed at 2,500 rpm for approx. 90 seconds.
(b) Check the idle speed.
Idle speed:
700 + 50 rpm
4. ADJUST IGNITION TIMING
(a) Using SST, connect terminals TE1 and E1 of the DLC 1.
SST 09843±18020
(b) Using a timing light, check the ignition timing.
Ignition timing:
10 + 2° BTDC @ idle
(Transmission in neutral position)
(c) Loosen the nut, and adjust by turning the distributor.
Ignition timing:
10° BTDC @ idle
(Transmission in neutral position)
(d) Tighten the nut, and recheck the ignition timing.
Torque: 19 NVm (195 kgfVcm, 14 ftVlbf)
(e) Remove the SST from the DLC1.
SST 09843±18020
5. FURTHER CHECK IGNITION TIMING
Ignition timing:
7±19° BTDC @ idle
(Transmission in neutral position)
HINT: The timing mark moves in a range between 75 and 195.
6. DISCONNECT TACHOMETER AND TIMING LIGHT
± ENGINEENGINE MECHANICALEG±19

IGNITION TIMING INSPECTION
(2JZ±GTE)
1. WARM UP ENGINE
Allow the engine to warm up to normal operating tempera-
ture.
2. CONNECT TACHOMETER AND TIMING LIGHT
(See step 2 in ignition timing inspection and adjustment
(2JZ±GE))
3. CHECK IDLE SPEED
(a) Race the engine speed at 2,500 rpm for approx. 90 seconds.
(b) Check the idle speed.
Idle speed:
650 + 50 rpm
4. CHECK IGNITION TIMING
(a) Using SST, connect terminals TE1 and E1 of the DLC 1.
SST 09843±18020
(b) Open the igniter connector cover and remove the green lead
wire.
(c) Connect the timing light clip to the green lead wire.
NOTICE:
wUse a timing light that can detect the primary signal.
wAfter finishing the inspection, make sure the lead wire is
stored inside the connector cover.
EG±20± ENGINEENGINE MECHANICAL

(d) Using a timing light, check the ignition timing.
Ignition timing:
10 + 25 BTDC @ idle
(Transmission in neutral position)
If the ignition timing is not as specified, check the valve tim-
ing. (See step 14 in timing belt installation)
(e) Remove the SST from the DLC1.
SST 09843±18020
5. FURTHER CHECK IGNITION TIMING
Ignition timing:
10±205 BTDC @ idle
(Transmission in neutral position)
HINT: The timing mark moves in a range between 10° and
20°.
6. DISCONNECT TACHOMETER AND TIMING LIGHT
IDLE SPEED INSPECTION
1. INITIAL CONDITIONS
(a) Engine at normal operating temperature
(b) Air cleaner installed
(c) All pipes and hoses of air induction system connected
(d) All accessories switched OFF
(e) All vacuum lines properly connected
HINT: All vacuum hoses for EGR system, etc. should be prop-
erly connected.
(f) SFI system wiring connectors fully plugged
(g) Ignition timing set correctly
(h) Transmission in neutral position
2. CONNECT TACHOMETER
(See step 2 in ignition timing inspection and adjustment
(2JZ±GE))
3. INSPECT IDLE SPEED
(a) Race the engine speed at 2,500 rpm for approx. 90 seconds.
(b) Check the idle speed.
Idle speed:
2JZ±GE
700 + 50 rpm
2JZ±GTE
650 + 50 rpm
If the idle speed is not as specified, check the IAC valve. (See
on±vehicle inspection in ISC valve in SFI System)
4. DISCONNECT TACHOMETER
± ENGINEENGINE MECHANICALEG±21