Compression
Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer manual for specific instructions.
| 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 | |
|---|---|---|
| Compression Ratio | 9.0:1 | |
| Normal Compression Pressure | ||
| Camry | 178 psi (12.5 kg/cm 2 ) | |
| Pickup & 4Runner | 171 psi (12.0 kg/cm 2 ) | |
| Minimum Compression Pressure | 142 psi (10.0 kg/cm 2 ) | |
| Maximum Variation Between Cylinders | 14 psi (1.0 kg/cm 2 ) | |
COMPRESSION SPECIFICATIONS
Exhaust System Backpressure
The exhaust system can be checked with a vacuum or pressure gauge. Remove O2 sensor or air injection check valve (if equipped). Connect a 1-10 psi pressure gauge and run engine at 2500 RPM. If exhaust system backpressure is greater than 2 psi, exhaust system or catalytic converter is plugged.
If a vacuum gauge is used, connect vacuum gauge hose to intake manifold vacuum port and start engine. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge reading slowly drops after stabilizing, exhaust system should be checked for a restriction.
FUEL SYSTEM
Basic diagnosis of fuel system should begin with determining fuel system operation and pressure.
| WARNING | ALWAYS relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components. |
Fuel Pressure Release
Disconnect negative battery terminal. Place container under fitting to be loosened. Use a rag to cover fuel line/component. Slowly loosen fitting, allowing pressurized fuel to spill into container. After fuel system has depressurized, disconnect and plug fitting.
EFI Main Relay
- EFI fuse supplies constant battery voltage to EFI main relay. EFI main relay provides battery voltage to +B terminal of circuit opening relay and engine check connector.
- If fuel pump does not turn on when +B and FP pins are jumpered with ignition on, check EFI main relay. (Scheme 36) Also check EFI main relay circuit. Depending on model, relay may either be turned on directly by ignition switch or by M-REL terminal of ECU. For more information on wiring, see WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section in ENGINE PERFORMANCE.
Scheme 36
Circuit Opening Relay
- Circuit opening relay controls fuel pump circuit. ECU receives an input signal at STA terminal when engine is cranking. This starter signal is also applied to terminal STA of circuit opening relay.
- Starter signal energizes circuit opening relay during cranking, which in turn activates fuel pump. Fuel pump switch in airflow meter provides relay ground.
Note. For more information on testing relays and fuel system components, see I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
Code 12 (No RPM Signal)
ECU will store Code 12 in memory if it does not receive signal from either NE pick-up coil (RPM) or "G" pick-up coil (crank position) terminal within 2 seconds of engine cranking.
Code 13 (No RPM Signal)
ECU will store Code 13 in memory if it does not receive signal from NE pick-up coil (RPM) terminal when engine speed is above 1000 RPM.
Code 14 (Ignition Signal Problem)
ECU will store Code 14 in memory if it does not receive IGF (ignition detection) signal a specified number of times. See CODE 14 SET SPECIFICATIONS table.
| Application | No. Times W/O IGF Signal |
|---|---|
| Camry | 4-5 |
| Pickup & 4Runner | 6-8 |
CODE 14 SET SPECIFICATIONS
PICK-UP COIL AIR GAP CHECK
- Using a flat, non-magnetic feeler gauge, check air gap between signal rotor and pick-up coil projection. (Scheme 37)& 11.
- Air gap should be within specification. See PICK-UP COIL ADJUSTMENT table. If air gap is not within specification, replace distributor.
| Application | In. (mm) |
|---|---|
| Camry | (1) At Least .008 (.20) |
| Pickup & 4Runner | (1) .008-.016 (.20-.40) |
| (1) Replace distributor if not within specification. | |
| (1) | Replace distributor if not within specification. |
PICK-UP COIL ADJUSTMENT
Scheme 37
Scheme 38
IDLE SPEED & IGNITION TIMING
Ensure idle speed and ignition timing are set to specification. For adjustment procedures, see ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
IDLE SPEED
| Application | RPM |
|---|---|
| Camry | 700 |
| Pickup & 4Runner | 800 |
IDLE SPEED SPECIFICATIONS
IGNITION TIMING
| Application | Base Timing | Advance Timing |
|---|---|---|
| Camry | 10 @ 700 | 13-27 @ Idle |
| Pickup & 4Runner | 10 @ 800 | 8 @ Idle |
IGNITION TIMING
SUMMARY
If no faults were found while performing BASIC TESTING , proceed to TESTS W/CODES article in the ENGINE PERFORMANCE Section. If no hard codes are found in self-diagnostics, proceed to TESTS W/O CODES article in the ENGINE PERFORMANCE Section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.