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 | 218 psi (15.3 kg/cm 2 ) |
| Minimum Compression Pressure | 145 psi (10.1 kg/cm 2 ) |
| Maximum Variation Between Cylinders | 15 psi (1.1 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 11) 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 11) 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-21922-S17188847882001010300000) 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-21922-S24009821022001010300000) 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-21922-S24009821022001010300000) 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 11
Note. For more information on checking fuel injectors and other fuel sub-systems, see SYSTEM/COMPONENT TESTS article.
| Application | Pressure psi (kg/cm 2 ) |
|---|---|
| Camry | (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 ) |
|---|---|---|
| Camry | 33-38 (2.3-2.7) | 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 - 3.0L 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 ignition is turned on, voltage is supplied through IGN fuse to EFI main relay. EFI main relay is then energized and 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 Engine Control Module (ECM) when ignition is turned on. The EFI main relay is located in engine compartment relay box.
Note. Circuit opening relay is used on all models except Supra. Supra uses EFI main relay, No. 2 EFI relay (Turbo models) and fuel pump Electronic Control Unit (ECU) for controlling fuel pump.
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 engine is cranking, circuit opening relay receives a start signal which energizes circuit opening relay. Circuit opening relay then provides voltage to fuel pump for fuel pump operation. When start signal is released from circuit opening relay and engine is running, the Engine Control Module (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 for fuel pump operation.
IGNITION COIL RESISTANCE
- Remove necessary components and disconnect electrical connector from ignition coil. Disconnect spark plug wire from ignition coil.
- Using ohmmeter, check ignition coil primary resistance between ignition coil positive (+) and negative (-) terminals. These are the terminals that electrical connector was installed on. (Scheme 12)and (Scheme 13). Replace ignition coil if primary resistance is not within specification. See «IGNITION COIL RESISTANCE»(ref-21922-S03510616332001010300000) table.
- Using ohmmeter, check ignition coil secondary resistance. (Scheme 12)and (Scheme 13). Replace ignition coil if secondary resistance is not within specification. See «IGNITION COIL RESISTANCE»(ref-21922-S03510616332001010300000) table. Reinstall connector on ignition coil.
| Application | Primary | Secondary |
|---|---|---|
| Cold (1) | .70-.94 | 10,800-14,900 |
| Hot (2) | .85-1.10 | 13,100-17,500 |
| (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
Scheme 12
Scheme 13
CAMSHAFT POSITION SENSOR
- Disconnect electrical connector from camshaft position sensor, located on rear of front (radiator side) cylinder head, just below valve cover. (Scheme 14) Using ohmmeter, check resistance between electrical terminals on camshaft position sensor.
- Replace camshaft position sensor if resistance is not within specification. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-21922-S21047681642001010300000) table. Reinstall electrical connector on camshaft position sensor.
| Application | Ohms |
|---|---|
| Cold (1) | 835-1400 |
| Hot (2) | 1060-1645 |
| (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). |
CAMSHAFT POSITION SENSOR RESISTANCE
Scheme 14
CRANKSHAFT POSITION SENSOR
- Disconnect electrical connector from crankshaft position sensor, located just above crankshaft pulley. (Scheme 15)
- Manufacturer recommends removing crankshaft position sensor before checking the resistance. Remove bolt and crankshaft position sensor.
- Using ohmmeter, check resistance between electrical terminals on crankshaft position sensor. Replace crankshaft position sensor if resistance is not within specification. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-21922-S27383345852001010300000) table.
- Reinstall crankshaft position sensor. Install and tighten crankshaft position sensor bolt to 71 INCH lbs. (8.0 N.m). 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 15
IDLE SPEED & IGNITION TIMING
Ensure idle speed and ignition timing are set to specs. For adjustment procedures, see ADJUSTMENTS - 3.0L V6 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.