Engine Controls - Remove/install/overhaul Lexus LS I

INTRODUCTION

Removal, overhaul and installation procedures (when given by manufacturer) are covered in this article. If component removal and installation is primarily an unbolt and bolt-on procedure, only a torque specification may be furnished.

REMOVAL (ES250)

1. Disconnect airflow meter connector. Disconnect air hoses. Loosen air cleaner hose clamp bolt. Disconnect air cleaner cover clips. Remove air cleaner cover and airflow meter together with air cleaner hose.
2. Remove spark plug and coil wires. Disconnect distributor connector. Remove 2 hold-down bolts and distributor. Remove "O" ring.

Scheme 1

1. Set No. 1 cylinder to TDC on compression stroke. Install new "O" ring onto distributor housing. Coat "O" ring with oil. Align cutout marks of coupling and housing. (Scheme 1) Install distributor and lightly tighten hold-down bolts.
2. Reconnect spark plug and coil wires and distributor connector. Install airflow meter, air cleaner cover and hoses. Start engine and allow to warm up. Connect tachometer and timing light. Set timing to specifications. See IGNITION TIMING in SPECIFICATIONS article.

Scheme 2

1. To remove right side distributor, remove air duct. Disconnect airflow meter connector. Loosen clamp bolt and disconnect air hose. Remove 2 bolts and airflow meter assembly. Remove throttle body cover.
2. Disconnect ISC air hose, power steering idle-up air hose and 2 bolts and main air hose. Remove 2 bolts and spark plug and coil wire cover. Remove one bolt and spark plug wire cover from engine. Remove 4 bolts and No. 3 timing belt cover and 3 gaskets. (Scheme 2)
3. Disconnect sensor connector. Remove 5 bolts, wire boot and No. 2 timing belt cover with 4 gaskets. (Scheme 2) Disconnect high tension wires from distributor cap. Remove distributor cap. Remove 2 screws and rotor. Remove 3 bolts and distributor. Sensor can be removed at this time.
4. To remove left side distributor, drain engine coolant. Remove 2 bolts and engine wire cover. Remove junction block cover. Remove 4 screws and No. 3 timing belt cover with 4 gaskets. (Scheme 2) Disconnect coolant hoses from coolant inlet housing. Disconnect hoses from reservoir tank. Remove 2 bolts, connector boot and No. 2 timing belt cover with 2 gaskets. (Scheme 2)
5. Remove spark plug wires from distributor. Remove distributor cap. Remove 2 screws and rotor. Remove 3 bolts and distributor housing. Sensor can be removed at this time.

INSTALLATION

1. To install, reverse removal procedure. Refill and bleed cooling system. Start engine and allow to warm up. Connect tachometer and timing light. Ensure timing is within specification. See IGNITION TIMING in SPECIFICATIONS article.
2. If timing is not within specification, ensure the following conditions are normal: Throttle valve is fully closed. Continuity exists between throttle position sensor terminals IDL and E2. Valve timing is correct.

FUEL SYSTEM PRESSURE RELEASE

To relieve fuel pressure, wrap cold start injector feed pipe banjo bolt with shop towel. Slowly loosen banjo bolt to relieve pressure. With a dry shop towel, pick up any fuel which may have run onto the engine.

REMOVAL (LS400)

1. Disconnect negative battery cable and drain engine coolant. Remove air cleaner with airflow meter. Remove throttle body and left engine wire harness cover. Disconnect ISC valve electrical connector, cold start injector connector, EGR VSV connector and EGR gas temperature sensor connector.
2. Disconnect power steering idle-up hose from intake chamber. Disconnect brake booster hose from intake chamber. Disconnect PCV hose from EGR adapter, 3 vacuum hoses from air pipe, 2 vacuum hoses from EGR VSV and EGR vacuum modulator hoses. Remove EGR vacuum modulator. Remove 3 bolts and air pipe. Disconnect coolant by-pass pipe.
3. Remove 2 bolts and accelerator cable and bracket. Disconnect cold start injector fuel delivery pipe. Remove 2 bolts and disconnect EGR pipe from air intake chamber and remove gasket. Remove 4 bolts and 8 nuts, throttle cable clamp, 2 VSV's, check connector and air intake chamber.
4. Disconnect cold start injector connector. Remove banjo bolt, cold start injector tube and 2 gaskets. Remove 2 bolts and cold start injector and gasket

1. Install cold start injector with new gasket and tighten to specifications. See LS400 TORQUE SPECIFICATIONS table in this article. Install cold start injector tube and banjo bolt with new gaskets, tighten to specification. Install air intake chamber with new gaskets and tighten to specification.
2. To complete installation, reverse removal procedure. See LS400 TORQUE SPECIFICATIONS in this article for proper specifications. Fill cooling system with proper mix of coolant. Ensure cooling system is properly bled. Start engine and inspect carefully to ensure there are no fuel or coolant leaks.

REMOVAL & INSTALLATION (ES250)

Disconnect negative battery cable. Drain fuel from tank. Remove fuel tank. Remove 8 bolts and fuel pump assembly. To install, reverse removal procedure.

REMOVAL & INSTALLATION (LS400)

Disconnect negative battery cable. Drain fuel from tank. Remove front luggage compartment cover. Remove rear seat back. Remove partition panel plug. Disconnect fuel pump electrical connector. Remove 8 bolts and fuel pump assembly. To install, reverse removal procedure.

1. Disconnect negative battery cable. Drain engine coolant. Disconnect throttle cable from throttle body and bracket (automatic transmission). Disconnect accelerator cable and bracket from throttle body and air intake chamber.
2. Remove air cleaner cover, airflow meter and air cleaner hose. Disconnect PCV hoses, vacuum sensing hose, water by-pass hose, fuel pressure VSV hose, emission control vacuum hoses, ISC connector, throttle position sensor connector and EGR gas temperature sensor.
3. Remove 3 bolts and right engine mounting stay. Disconnect cold start injector connector. Disconnect cold start injector tube banjo bolt. Disconnect brake booster vacuum hose, power steering vacuum and air hoses, cruise control vacuum hose, ground strap connector and wire harness clamp.
4. Disconnect EGR pipe. Remove 2 bolts and engine hanger. Remove bolt and disconnect air intake chamber stay from air intake chamber. Remove 2 bolts, nuts, air intake chamber and gasket. Disconnect coolant temperature connector. Disconnect 6 injector connectors. Disconnect wire harness from left fuel rail.
5. Disconnect fuel return hose from fuel pressure regulator. Disconnect fuel inlet hose from fuel filter. Remove 2 banjo bolts, 4 gaskets and left fuel pipe. Remove 2 bolts and left fuel rail together with 3 injectors. Remove 3 bolts and right fuel rail together with 3 injectors. To remove injectors from fuel rail, pull with a slight twisting motion.

Scheme 3

1. Install new "O" rings and grommets on injectors. With a twisting motion, push injectors onto fuel rail. (Scheme 3) Place 6 insulators and 4 spacers in position on intake manifold. Place fuel rails and injectors in position on intake manifold. Install mounting bolts and tighten to specifications. See ES250 TORQUE SPECIFICATIONS in this article.
2. To complete installation, reverse removal procedure. See ES250 TORQUE SPECIFICATIONS in this article for proper specifications. Fill cooling system with proper mix of coolant. Turn ignition on and using a jumper wire, connect terminals +B and FP of the check connector. (Scheme 4) Pinch fuel return hose to raise fuel pressure in system. Inspect carefully to ensure there are no fuel leaks.

Scheme 4

1. To remove right fuel injectors and fuel rail, disconnect negative battery cable. Remove air cleaner and airflow meter. Remove right and left engine wire covers. Remove right and left No. 3 timing belt covers. (Scheme 2) Remove high tension wire covers.
2. Remove 2 bolts and remove engine wire harness from fuel rail. Disconnect coolant temperature gauge sender connector, coolant temperature sensor connector, cold start injector time switch connector and injector connectors. Disconnect fuel return pipe, cold start injector tube and front fuel pipe.
3. Remove 2 banjo bolts, 4 gaskets and rear fuel pipe. Leave rear fuel pipe on vehicle. Remove vacuum hose from fuel pressure regulator. Remove 2 nuts and fuel rail with injectors.
4. To remove left fuel injectors and fuel rail, disconnect negative battery cable and drain engine coolant. Disconnect PCV hose. Remove high tension wire cover and engine wire cover. Disconnect 4 vacuum hoses from air pipe. Disconnect vacuum hose from BVSV, 2 hoses from EGR VSV and EGR vacuum modulator hose.
5. Remove EGR vacuum modulator with bracket. Disconnect check connector from bracket. Disconnect connectors from 2 VSV's then remove VSV's. Remove 2 coolant by-pass pipes. Remove 2 bolts and disconnect engine wire harness from fuel rail. Disconnect distributor connector, engine speed sensor connector, EGR gas temperature sensor connector and 4 injector connectors.
6. Remove bolt, pulsation damper and 2 gaskets. Disconnect fuel inlet hose from fuel rail. Disconnect front fuel pipe. Remove rear fuel pipe as outlined in step 3). Remove 2 nuts and fuel rail with injectors.

1. Install new "O" rings and grommets on injectors. With a twisting motion, push injectors onto fuel rail. (Scheme 3) Install insulators into injector holes in intake manifold. Install injectors together with fuel rail and lightly tighten nuts. Ensure injectors rotate smoothly left and right. If they do not, recheck "O" ring installation.
2. To complete installation, reverse removal procedure. See LS400 TORQUE SPECIFICATIONS in this article for proper specifications. Fill cooling system with proper mix of coolant. Ensure cooling system is properly bled. Start engine and inspect carefully to ensure there are no fuel or coolant leaks.

REMOVAL & INSTALLATION

Exhaust gas oxygen (O2) sensor is mounted in the exhaust pipe just below the exhaust header. When removing sensor, ensure its permanent pigtail is protected from damage. Ensure sensor is free of contaminants, and remove from header. Avoid using cleaning solvents of any type. If engine temperature is less than 120°F (48°C), sensor may be difficult to remove. To install, apply anti-seize compound on sensor threads. Turn sensor into header, and tighten to 33 ft. lbs. (44 N.m).

TORQUE SPECIFICATIONS (ES250)

ES250 TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS (LS400)

LS400 TORQUE SPECIFICATIONS