Engine Controls - Adjustments Toyota Supra A80

INTRODUCTION

Note. Introduction information not applicable.

ENGINE MECHANICAL

Before performing any on-vehicle adjustments to fuel or ignition systems, ensure engine mechanical condition is okay.

Scheme 1

Scheme 2

Scheme 3

1. Check valve clearance with engine cold. Remove upper timing belt cover, valve covers and gaskets. CAUTION: Ensure crankshaft is always rotated clockwise.
2. Rotate crankshaft pulley clockwise so crankshaft pulley groove aligns with "0" mark on timing belt cover and cylinder No. 1 (front cylinder) is at TDC on compression stroke. Ensure timing marks on camshaft sprockets are aligned with timing marks on timing belt cover. (Scheme 1) If timing marks are not aligned, rotate crankshaft pulley clockwise one full revolution (360 degrees).
3. Using feeler gauge, measure and record valve clearance of intake valves on cylinders No. 1, 2 and 4 and exhaust valves on cylinders No. 1, 3 and 5. (Scheme 2)
4. Rotate crankshaft pulley clockwise one full revolution (360 degrees) and realign crankshaft pulley groove with "0" mark on timing belt cover. Using feeler gauge, measure and record valve clearance of intake valves on cylinders No. 3, 5 and 6 and exhaust valves on cylinders No. 2, 4 and 6. (Scheme 2)
5. Ensure valve clearance is within specification. See the «VALVE CLEARANCE SPECIFICATIONS»(/toyota/supra/a80-1993-1996/remont/adjustments/#engine-controls-adjustments) table. VALVE CLEARANCE SPECIFICATIONS Application (1) In. (mm) Exhaust.010-.014 (.25-.35) Intake.006-.010 (.15-.25) (1) Adjust valve clearance with engine cold. SHIM THICKNESS Thickness mm (in.) Shim No. 2.50 (0.0984) 1 2.55 (0.1004) 2 2.60 (0.1024) 3 2.65 (0.1043) 4 2.70 (0.1063) 5 2.75 (0.1083) 6 2.80 (0.1102) 7 2.85 (0.1122) 8 2.90 (0.1142) 9 2.95 (0.1161) 10 3.00 (0.1181) 11 3.05 (0.1201) 12 3.10 (0.1220) 13 3.15 (0.1240) 14 3.20 (0.1260) 15 3.25 (0.1280) 16 3.30 (0.1299) 17
6. If valve clearance adjustment is required, rotate crankshaft pulley so camshaft lobe is facing upward on valve to be adjusted. Position adjusting shim notch area so notch area is at 90-degree angle to camshaft. This will place notch area perpendicular to camshaft.
7. Valve Clearance Adjuster (SST 09248-55040) is used for adjusting valve clearance. Press valve lifter downward using SST "A" of valve clearance adjuster. (Scheme 3) Install SST "B" between camshaft and valve lifter. Remove SST "A".
8. Using small screwdriver and magnet, remove adjusting shim. Using micrometer, measure thickness of removed adjusting shim. Using measured clearance and adjusting shim thickness, determine correct thickness of adjusting shim to be used. See «SHIM THICKNESS»(/toyota/supra/a80-1993-1996/remont/adjustments/#engine-controls-adjustments) table.
9. Install proper adjusting shim with imprinted numbers on adjusting shim facing downward. Using SST "A", press downward on valve lifter and remove SST "B". Recheck valve clearance. See SHIM THICKNESS table. Shim thickness can also be determined by using the following formula: N = T + A. N = Thickness of adjuster shim required. T = Thickness of adjuster shim removed. A = Measured clearance minus valve clearance specification.
10. Apply sealant at front camshaft bearing caps-to-cylinder head surfaces where valve cover gasket seals. Install valve covers using NEW gaskets. Install upper timing belt cover.

IGNITION TIMING

1. Warm engine to normal operating temperature. Shut engine off. Connect tachometer to proper terminals of data link connector. (Scheme 5)and (Scheme 6).
2. Open cover located above the ignitor. Connect timing light lead to Green wire and to battery. (Scheme 4) Ignitor is located near driver's side strut tower.
3. On all models, apply parking brake and start engine. Hold engine RPM at 2500 RPM for about 90 seconds. Ensure idle speed is within specification with transmission/transaxle in Neutral and all accessories off. See «6-CYLINDER IDLE SPEED SPECIFICATIONS»(/toyota/supra/a80-1993-1996/remont/adjustments/#engine-controls-adjustments) table.
4. Shut engine off. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 of data link connector located in engine compartment. (Scheme 5) Start engine. NOTE: Timing marks are located on front cover.
5. Ensure base timing is within specification with engine idling at specified RPM and transmission/transaxle in Neutral. See the «6-CYLINDER IGNITION TIMING»(/toyota/supra/a80-1993-1996/remont/adjustments/#engine-controls-adjustments) table.
6. If ignition timing is incorrect, check valve timing by ensuring proper alignment of timing belt. See ENGINES article in ENGINE MECHANICAL section.
7. On all models, remove jumper wire from data link connector. Ensure advance timing is within specification. Refer to the «6-CYLINDER IGNITION TIMING»(/toyota/supra/a80-1993-1996/remont/adjustments/#engine-controls-adjustments) table. Shut engine off. Remove timing light and reinstall components.

Scheme 4

6-CYLINDER IGNITION TIMING

Scheme 5

Scheme 6

IDLE SPEED & MIXTURE

Note. Mixture adjustment is not possible on any model.

6-CYLINDER IDLE SPEED

Note. Check idle speed with air cleaner installed, all air intake system hoses and vacuum lines connected, electronic fuel injection system wiring connectors tight, transmission in Neutral, all accessories and electric cooling fan off (if equipped), and engine at normal operating temperature.

1. Install tachometer on proper terminals of data link connector. (Scheme 5) Start and operate engine at 2500 RPM for about 90 seconds.
2. Allow engine to idle. Ensure idle speed is within specification. See «6-CYLINDER IDLE SPEED SPECIFICATIONS»(/toyota/supra/a80-1993-1996/remont/adjustments/#engine-controls-adjustments) table.
3. If idle speed is not within specification, check Idle Air Control (IAC) valve, wiring and Electronic Control Module (ECM). See IDLE CONTROL SYSTEM in «SYSTEM/COMPONENT TESTS»(ref-21358) article. Remove tachometer.

6-CYLINDER IDLE SPEED SPECIFICATIONS

THROTTLE POSITION SENSOR

Note. Supra 3.0L Turbo (2JZ-GTE) contains a main throttle position sensor and a sub-throttle position sensor on throttle body. (Scheme 9) Following procedure is for main throttle position sensor. For adjustment of sub-throttle position sensor, see SUB-THROTTLE POSITION SENSOR.

1. Disconnect electrical connector from Throttle Position Sensor (TPS). Loosen TPS mounting screws. Connect ohmmeter between terminals IDL and E2. (Scheme 7)and (Scheme 8).
2. Apply vacuum to throttle opener (if equipped). To set initial clearance, insert proper thickness feeler gauge between throttle stop screw and throttle lever. See «THROTTLE POSITION SENSOR ADJUSTMENT»(/toyota/supra/a80-1993-1996/remont/adjustments/#engine-controls-adjustments) table.
3. With ohmmeter showing no continuity, rotate TPS clockwise until continuity exists. Tighten TPS mounting screws. Using specified feeler gauge, recheck adjusted clearance. Disconnect ohmmeter. Install electrical connector on TPS.

THROTTLE POSITION SENSOR ADJUSTMENT

Scheme 7

Scheme 8

SUB-THROTTLE POSITION SENSOR

1. Remove screws and sub-throttle actuator. (Scheme 9) Disconnect electrical connector from sub-throttle position sensor.
2. Ensure no clearance exists between throttle stop screw and throttle valve gear with sub-throttle valve fully closed. Perform STEP 1. (Scheme 10)-12.
3. Place sub-throttle valve in fully closed position. Loosen sub-throttle position sensor mounting screws. Connect ohmmeter between terminals IDL and E2. Perform STEP 2. (Scheme 10)-12.
4. To set initial clearance, insert.018" (.45 mm) feeler gauge between throttle stop screw and throttle valve gear. Perform STEP 3. (Scheme 10)-12.
5. With ohmmeter showing no continuity, rotate sub-throttle position sensor clockwise until continuity exists. Tighten sub-throttle position sensor mounting screws.
6. Remove feeler gauge. Insert a.016" (.41 mm) feeler gauge. Ensure continuity still exists. Remove feeler gauge. Insert a.019" (.48 mm) feeler gauge. Ensure continuity no longer exists. Reinstall sub-throttle actuator. Install electrical connector on sub-throttle position sensor.

Scheme 9

Scheme 10

Scheme 11

Scheme 12

DASHPOT & THROTTLE VALVE OPENER CONTROL SYSTEM

For testing and adjustment procedures, see THROTTLE CONTROLS in SYSTEM/COMPONENT TESTS article.

See also:
• VALVE CLEARANCE SPECIFICATIONS
• SUB-THROTTLE POSITION SENSOR