Engine Controls - Basic Testing Toyota Land Cruiser 80 рестайлинг

INTRODUCTION

The following diagnostic steps will help prevent overlooking a simple problem. This is also where to begin diagnosis for a no-start condition.

The first step in diagnosing any driveability problem is verifying the customer's complaint with a test drive under the conditions problem reportedly occurred.

Before entering self-diagnostics, perform a careful and complete visual inspection. Most engine control problems result from mechanical breakdowns, poor electrical connections or damaged/misrouted vacuum hoses. Before condemning the computerized system, perform each test listed in this article.

Note. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.

VISUAL INSPECTION

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and are not pinched or cut. See VACUUM DIAGRAMS article to verify routing and connections (if necessary). Inspect air induction system for possible vacuum leaks.

Compression

Check engine mechanical condition with a compression gauge, vacuum gauge, or engine analyzer. See engine analyzer manual for specific instructions. See COMPRESSION SPECIFICATIONS table.

COMPRESSION SPECIFICATIONS

FUEL SYSTEM

Basic diagnosis of fuel system should begin by checking fuel pump operation and fuel pressure.

FUEL PUMP OPERATION

Note. Electric fuel pump operation may be checked by using scan tester or by applying battery voltage to fuel pump.

Checking Fuel Pump Operation Using Scan Tester

1. Remove cover (if equipped) and install scan tester on data link connector No. 3. (Scheme 1) Turn ignition on. DO NOT start engine.
2. Using scan tester manufacturer's instructions, activate fuel pump. Listen for fuel pump operating sound and feel for pressure in fuel inlet line near fuel filter. Turn ignition off. Remove scan tester. If fuel pump operates, check fuel pressure. See «FUEL PRESSURE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing__fuel-pressure).
3. If fuel pump does not operate, EFI main relay, circuit opening relay or fuel pump relay (if used) may be defective. For relay application and explanation of relay operation, see «FUEL PUMP CONTROL CIRCUIT»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing__fuel-pump-control-circuit).
4. If relays are okay, check wiring circuit and fuses. If fuel pump does not operate, check for defective fuel pump or defective fuel pump ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.

Checking Fuel Pump Operation By Applying Battery Voltage To Fuel Pump

1. Remove second seat, scuff plate, step plate, floor mats and cover plate on floor panel for access to electrical connector at fuel pump.
2. Disconnect electrical connector for fuel pump. NOTE: Electrical connector for fuel pump is located near fuel pump. CAUTION: When applying battery voltage to fuel pump, DO NOT apply battery voltage for more than 10 seconds, or fuel pump may be damaged.
3. Connect battery voltage to specified terminals on fuel pump to activate fuel pump. (Scheme 2) DO NOT apply battery voltage to fuel pump for more than 10 seconds.
4. Listen for fuel pump operating sound and feel for pressure in fuel line near fuel filter. If fuel pump operates, check fuel pressure. See «FUEL PRESSURE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing__fuel-pressure). Disconnect battery voltage from fuel pump.
5. If fuel pump fails to operate, replace fuel pump. If fuel pump will not operate while trying to start engine, EFI main relay, circuit opening relay or fuel pump relay (if used) may be defective. For explanation of relay operation, see «FUEL PUMP CONTROL CIRCUIT»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing__fuel-pump-control-circuit).
6. If relays are okay, check wiring circuit, fuses and fuel pump ground. See appropriate wiring diagram in WIRING DIAGRAMS article. Reinstall electrical connector and remaining components.

Scheme 1

Scheme 2

FUEL PRESSURE

Note. All models use in-tank fuel pump.

1. Ensure battery is fully charged and ignition is off. Disconnect negative battery cable.
2. Note location for fuel pressure gauge installation. (Scheme 3) Fuel pressure gauge may be installed on fuel filter or on delivery pipe depending on model application.
3. Place container under fuel filter or delivery pipe. Cover union bolt with shop towel. Slowly loosen union bolt to release fuel pressure.
4. Remove union bolt and gaskets. Install Fuel Pressure Gauge (SST 09268-45012) using NEW gaskets. (Scheme 3) Tighten union bolt. Reconnect negative battery cable.
5. Remove cover (if equipped) and install scan tester on data link connector No. 3. (Scheme 1) Turn ignition on. DO NOT start engine.
6. Using scan tester manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be within specification. See «FUEL PUMP PERFORMANCE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing) table. NOTE: Fuel pump may also be activated by connecting battery voltage to specified terminals on fuel pump. (Scheme 2)
7. If fuel pressure exceeds specification, replace fuel pressure regulator, located on the delivery pipe. If fuel pressure is less than specified, check for defective fuel lines, connections, fuel pump, fuel filter, fuel pressure regulator or fuel pressure control Vacuum Switching Valve (VSV) if equipped.
8. Turn ignition off. Remove scan tester from data link connector No. 3. Reinstall cover (if equipped). Start engine and allow engine to idle.
9. Disconnect and plug vacuum line at fuel pressure regulator. Note fuel pressure. Fuel pressure should be within specification. See «REGULATED FUEL PRESSURE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing) table.
10. Reconnect vacuum hose on fuel pressure regulator and note fuel pressure with engine idling. Fuel pressure should be within specification. See «REGULATED FUEL PRESSURE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing) table.
11. If fuel pressure is not within specification, check for defective vacuum hose or fuel pressure regulator. Shut engine off and note fuel pressure.
12. Fuel pressure should hold at least 21 psi (1.5 kg/cm 2 ) for a minimum of 5 minutes. If fuel pressure does not hold as specified, check for defective fuel pump, fuel injector or fuel pressure regulator.
13. Disconnect negative battery cable. Remove fuel pressure gauge. Reinstall union bolt using NEW gaskets. Tighten union bolt. Install negative battery cable. Recheck for fuel leaks.

Scheme 3

Note. For more information on checking fuel injectors and other fuel sub-systems, see SYSTEM/COMPONENT TESTS article.

FUEL PUMP PERFORMANCE

REGULATED FUEL PRESSURE

FUEL PUMP CONTROL CIRCUIT

Note. For information on testing relays and fuel system components, see SYSTEM/COMPONENT TESTS article. Relays may be identified by appropriate illustration in THEORY/OPERATION article. Vehicles are equipped with different combinations of fuel system electrical components. For complete wiring circuit of electrical components on a specific model, see appropriate wiring diagram in WIRING DIAGRAMS article.

EFI Main Relay

The EFI fuse supplies constant battery voltage to EFI main relay. When EFI main relay is energized by MRLY terminal of Engine Control Module (ECM), the EFI main relay provides battery voltage to circuit opening relay, data link connector No. 1 and various other electrical components. The EFI main relay also provides battery voltage to +B terminal of ECM when ignition is turned on. The EFI main relay is located in engine compartment relay box.

Circuit Opening Relay

Circuit opening relay controls the fuel pump circuit. When EFI main relay is energized, EFI main relay provides battery voltage to one side of circuit opening relay. When ignition is turned on, voltage is supplied to the other side of circuit opening relay. When engine is cranking and start signal is delivered to Engine Control Module (ECM), the circuit opening relay ground circuit is grounded at ECM terminal FC. Circuit opening relay then provides voltage to fuel pump relay for fuel pump operation. When start signal is released and engine is running, the ECM then uses engine speed input signal for controlling the ground circuit for circuit opening relay at ECM terminal FC. Circuit opening relay then provides voltage to fuel pump relay for fuel pump operation.

Fuel Pump Relay & Fuel Pump Resistor

Fuel pump speed is controlled at low speed or high speed depending on if engine is cranking or engine load. When engine is cranking and start signal is delivered to Engine Control Module (ECM), the circuit opening relay ground circuit is grounded at ECM terminal FC. Circuit opening relay then provides full battery voltage to fuel pump relay. Fuel pump relay delivers full battery voltage to fuel pump and fuel pump operates at high speed. When start signal is released and engine is idling or under light load, ECM then grounds the fuel pump relay at ECM terminal FPR. Fuel pump relay closes and provides voltage through the fuel pump resistor to the fuel pump. Fuel pump now operates at low speed.

SPARK TEST

1. Disconnect high tension coil wire from distributor cap. Hold coil wire approximately 1/2" away from body or engine ground. CAUTION: To prevent gasoline from being injected, DO NOT crank engine for longer than 2 seconds.
2. Crank engine and check for spark. If spark does exist, check ignition coil, igniter and distributor electrical connections.
3. If electrical connections are okay, go to next step. If electrical connections are defective, repair as necessary and recheck for spark.
4. Using ohmmeter, check resistance of spark plug and ignition coil high tension wires. Resistance should be within specification. See «HIGH TENSION WIRE RESISTANCE SPECIFICATIONS»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing) table. If resistance is within specification, go to next step. If resistance is not within specification, replace high tension wire. HIGH TENSION WIRE RESISTANCE SPECIFICATIONS Application Maximum Ohms Land Cruiser, LX450 25,000 Per Wire
5. Turn ignition on. Check for battery voltage at igniter and ignition coil positive terminal. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between ignition switch, ignition coil and igniter. See appropriate wiring diagram in WIRING DIAGRAMS article.
6. Check ignition coil resistance. See «IGNITION COIL RESISTANCE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing__ignition-coil-resistance) under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM). If ignition coil resistance is within specification, go to next step. If ignition coil resistance is not within specification, replace ignition coil.
7. Check pick-up coil resistance. See «PICK-UP COIL RESISTANCE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing__pick-up-coil-resistance) under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM). If pick-up coil resistance is within specification, go to next step. If pick-up coil resistance is not within specification, replace distributor assembly.
8. Check resistance of crankshaft position sensor. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing__crankshaft-position-sensor-resistance) under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM). If crankshaft position sensor resistance is within specification, go to next step. If crankshaft position sensor resistance is not within specification, replace crankshaft position sensor.
9. Check pick-up coil air gap. See «PICK-UP COIL AIR GAP»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing__pick-up-coil-air-gap) under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM). If pick-up coil air gap is correct, go to next step. If pick-up coil air gap is incorrect, replace distributor assembly.
10. Check ignition IGT signal from Engine Control Module (ECM). If ignition IGT signal from ECM is defective, a diagnostic trouble code P1300 will be set in the ECM memory to indicate a igniter circuit malfunction. See TESTS W/CODES article for diagnostic trouble code.
11. If IGT signal is okay, substitute another igniter and recheck system operation. If IGT signal is defective, check wiring between Engine Control Module (ECM), distributor and igniter. If wiring is defective, repair wiring as necessary and recheck system operation. If wiring is okay, substitute another ECM and recheck system operation.

CRANKSHAFT POSITION SENSOR RESISTANCE

1. Crankshaft position sensor is located on front of engine, just in front of the oil pan, below the crankshaft pulley. Disconnect electrical connector for crankshaft position sensor. (Scheme 4)
2. Using ohmmeter, check resistance between terminals on crankshaft position sensor. Replace crankshaft position sensor if resistance is not within specification. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing) table. Reinstall electrical connector.

CRANKSHAFT POSITION SENSOR RESISTANCE

Scheme 4

IGNITION COIL RESISTANCE

1. Disconnect wiring from ignition coil so ignition coil is isolated from system. Using ohmmeter, check ignition coil primary resistance between ignition coil positive (+) and negative (-) terminals. (Scheme 5)
2. Check ignition coil secondary resistance between ignition coil positive (+) terminal and high tension terminal (coil wire tower). (Scheme 6) Replace ignition coil if resistance is not within specification. See «IGNITION COIL RESISTANCE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing) table.

IGNITION COIL RESISTANCE - OHMS

Scheme 5

Scheme 6

PICK-UP COIL RESISTANCE

1. Disconnect electrical connector on distributor and note pick-up coil terminal identification on the distributor. (Scheme 7)
2. Using ohmmeter, check resistance between specified terminals. See «PICK-UP COIL RESISTANCE»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing) table. Replace distributor assembly if pick-up coil resistance is not within specification. Reinstall electrical connector.

PICK-UP COIL RESISTANCE

Scheme 7

PICK-UP COIL AIR GAP

1. Remove distributor cap. Using non-magnetic feeler gauge, check pick-up coil air gap between signal rotor and pick-up coil projection. (Scheme 8)
2. Replace distributor assembly if pick-up coil air gap is not within specification. See «PICK-UP COIL AIR GAP SPECIFICATIONS»(/toyota/land-cruiser/80-1995-1997/remont/testing-diagnostics/#engine-controls-basic-testing) table.

PICK-UP COIL AIR GAP SPECIFICATIONS

Scheme 8

IDLE SPEED & IGNITION TIMING

Ensure idle speed and ignition timing are set to specification. For adjustment procedures, see ADJUSTMENTS article.

SUMMARY

If no faults were found while performing BASIC TESTING , proceed to appropriate TESTS W/CODES article. If no hard diagnostic trouble codes are found in self-diagnostics, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

See also:
• THEORY/OPERATION
• ADJUSTMENTS
• COMPRESSION SPECIFICATIONS
• FUEL PRESSURE
• FUEL PUMP CONTROL CIRCUIT
• IGNITION COIL RESISTANCE
• PICK-UP COIL RESISTANCE
• CRANKSHAFT POSITION SENSOR RESISTANCE
• PICK-UP COIL AIR GAP