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.
| WARNING | DO NOT use ignition switch during compression tests. Use a remote starter to crank engine. Fuel injectors on many models are triggered by ignition switch during cranking mode, which can create a fire hazard or contaminate the engine's oiling system. |
| Application | Specification |
|---|---|
| Normal Compression Pressure | 171 psi (12.0 kg/cm 2 ) |
| Minimum Compression Pressure | 128 psi (9.0 kg/cm 2 ) |
| Maximum Variation Between Cylinders | 14 psi (1.0 kg/cm 2 ) |
COMPRESSION SPECIFICATIONS
FUEL SYSTEM
Basic diagnosis of fuel system should begin by checking fuel pump operation and fuel pressure.
| WARNING | ALWAYS release fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components. |
FUEL PRESSURE
Note. All models use in-tank fuel pump.
- Ensure battery is fully charged and ignition is off. Disconnect negative battery cable.
- 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.
- Place container under fuel filter or delivery pipe. Cover union bolt with shop towel. Slowly loosen union bolt to release fuel pressure.
- Remove union bolt and gaskets. Install Fuel Pressure Gauge (SST 09268-45012) using NEW gaskets. (Scheme 3) Tighten union bolt. Reconnect negative battery cable.
- Remove cover (if equipped) and install scan tester on data link connector No. 3. see scheme 1 Turn ignition on. DO NOT start engine.
- Using scan tester manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be within specification. See «FUEL PUMP PERFORMANCE»(ref-21926-S19544058712001010300000) table. NOTE: Fuel pump may also be activated by connecting battery voltage to specified terminals on fuel pump. see scheme 2
- 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.
- Turn ignition off. Remove scan tester from data link connector No. 3. Reinstall cover (if equipped). Start engine and allow engine to idle.
- Disconnect and plug vacuum line at fuel pressure regulator. Note fuel pressure. Fuel pressure should be within specification. See «REGULATED FUEL PRESSURE»(ref-21926-S18464545132001010300000) table.
- Reconnect vacuum hose on fuel pressure regulator and note fuel pressure with engine idling. Fuel pressure should be within specification. See «REGULATED FUEL PRESSURE»(ref-21926-S18464545132001010300000) table.
- If fuel pressure is not within specification, check for defective vacuum hose or fuel pressure regulator. Shut engine off and note fuel pressure.
- 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.
- 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.
| Application | Pressure psi (kg/cm 2 ) |
|---|---|
| Land Cruiser, LX450 | (1) 38-44 (2.7-3.1) |
| (1) Check fuel pressure with engine off and using scan tester connected to data link connector No. 3 with ignition on to activate fuel pump or by connecting battery voltage to terminals on fuel pump. | |
| (1) | Check fuel pressure with engine off and using scan tester connected to data link connector No. 3 with ignition on to activate fuel pump or by connecting battery voltage to terminals on fuel pump. |
FUEL PUMP PERFORMANCE
| Application Type Tested | At Idle W/Vacuum psi (kg/cm 2 ) | At Idle W/O Vacuum psi (kg/cm 2 ) |
|---|---|---|
| Land Cruiser, LX450 | 31-37 (2.2-2.6) | 38-44 (2.7-3.1) |
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.
CRANKSHAFT POSITION SENSOR RESISTANCE
- 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)
- 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»(ref-21926-S32490058832001010300000) table. Reinstall electrical connector.
| Application | Ohms |
|---|---|
| Cold (1) | 1630-2740 |
| Hot (2) | 2065-3225 |
| (1) Cold is with temperature of 14-122°F (-10-50°C). (2) Hot is with temperature of 122-212°F (50-100°C). | |
| (1) | Cold is with temperature of 14-122°F (-10-50°C). |
| (2) | Hot is with temperature of 122-212°F (50-100°C). |
CRANKSHAFT POSITION SENSOR RESISTANCE
Scheme 4
IGNITION COIL RESISTANCE
- 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)
- 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»(ref-21926-S22097277452001010300000) table.
| Application | Primary | Secondary |
|---|---|---|
| Cold (1) | .36-.55 | 9000-15,400 |
| Hot (2) | .45-.65 | 11,400-18,100 |
| (1) Cold is with temperature of 14-122°F (-10-50°C). (2) Hot is with temperature of 122-212°F (50-100°C). | ||
| (1) | Cold is with temperature of 14-122°F (-10-50°C). |
| (2) | Hot is with temperature of 122-212°F (50-100°C). |
IGNITION COIL RESISTANCE - OHMS
Scheme 5
Scheme 6
PICK-UP COIL RESISTANCE
- Disconnect electrical connector on distributor and note pick-up coil terminal identification on the distributor. (Scheme 7)
- Using ohmmeter, check resistance between specified terminals. See «PICK-UP COIL RESISTANCE»(ref-21926-S05102505142001010300000) table. Replace distributor assembly if pick-up coil resistance is not within specification. Reinstall electrical connector.
| Application | Pick-Up Coil Terminals | Ohms |
|---|---|---|
| Cold (1) | G1 & G | 185-275 |
| Cold (1) | G2 & G | 185-275 |
| Cold (1) | NE & G | 185-275 |
| Hot (2) | G1 & G | 240-325 |
| Hot (2) | G2 & G | 240-325 |
| Hot (2) | NE & G | 240-325 |
| (1) Cold is with temperature of 14-122°F (-10-50°C). (2) Hot is with temperature of 122-212°F (50-100°C). | ||
| (1) | Cold is with temperature of 14-122°F (-10-50°C). |
| (2) | Hot is with temperature of 122-212°F (50-100°C). |
PICK-UP COIL RESISTANCE
Scheme 7
PICK-UP COIL AIR GAP
- Remove distributor cap. Using non-magnetic feeler gauge, check pick-up coil air gap between signal rotor and pick-up coil projection. (Scheme 8)
- Replace distributor assembly if pick-up coil air gap is not within specification. See «PICK-UP COIL AIR GAP SPECIFICATIONS»(ref-21926-S24562218782001010300000) table.
| Application | In. (mm) |
|---|---|
| Land Cruiser, LX450 | .008-.016 (.20-.40) |
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.