Toyota Pick-ups, Land Cruiser, and 4 Runner 1997-00

Ignition Timing

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GENERAL INFORMATION





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Fig. The ignition timing marks can usually be found stamped into a bracket located just above the crankshaft accessory drive pulley

Ignition timing is the measurement in degrees of crankshaft rotation at the instant the spark plug fires while the piston is on its compression stroke.

Ideally, the air/fuel mixture in the cylinder will be ignited by the spark plug and just beginning its rapid expansion as the piston passes Top Dead Center (TDC) of the compression stroke. If this happens, the piston will be beginning the power stroke just as the compressed air/fuel mixture starts to burn and expand. The expansion (explosion) of the air/fuel mixture will then force the piston down on the power stroke and turn the crankshaft.

It takes a fraction of a second for the spark from the plug to completely ignite the mixture in the cylinder. Because of this, the spark plug must fire before the piston reaches TDC, if the mixture is to be completely ignited as the piston passes TDC. This measurement is given in degrees of crankshaft rotation before the piston reaches top dead center (BTDC). If the ignition timing setting for your engine is 7 degrees BTDC, this means that the spark plug must fire at the time when the piston for that cylinder is 7 degrees before reaching the top of its compression stroke. However, this only holds true while your engine is at idle speed.

As the engine accelerates from idle, the speed of the engine (rpm, or revolutions per minute) increases. The increase in rpm means that the pistons are now traveling up and down much faster. Because of this, the spark plugs will have to fire even sooner if the mixture is to be completely ignited as the piston passes TDC. To accomplish this, the truck's on-board computer (ECU) controls the timing of the spark as engine speed increases.

The ignition timing on the Toyota trucks covered by this guide is regulated completely by the Electronic Control Unit (ECU). On some engines, the timing can checked and adjusted using a timing light. On other engines, the timing cannot be adjusted.

The electronic control of the ignition timing function is known as Electronic Spark Advance (ESA) and is accomplished by Toyota's programming of the ECU. By monitoring the rpm, intake air volume, engine temperature, throttle position and other variables, the microprocessor decides the correct moment to trigger the spark for any engine operating condition from cold idle through wide open throttle. The system is simple, non-adjustable and reliable.

1FZ-FE Engine

Toyota's hand-held tester or an equivalent OBD-II scan tool must be used for this procedure.

  1. Warm the engine to normal operating temperature.
  2.  
  3. Connect an OBD-II compliant scan tool to the DLC3 located under the dash on the driver's side. For additional information, please refer to the following topic(s): Drivability and Emission Controls, Reading Codes.
  4.  



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Fig. An OBD-II compliant scan tool must be connected to DLC3

  1. Connect the timing light to the engine.
  2.  
  3. Race the engine to 2500 rpm for approximately 90 seconds. Check the idle speed. It should read 600700 rpm.
  4.  
  5. Using SST 09843-18020 or its equivalent jumper wire, connect terminals TE1 and E1 of the DLC1 under the hood.
  6.  



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Fig. SST 09843-18020 or a jumper wire may be used to connect terminals TE1 and E1 of the DLC1

  1. With the transmission in neutral and the A/C off, check the timing. It should read 3°BTDC at idle.
  2.  



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Fig. The timing should be 3°BTDC at idle1FZ-FE engine

  1. Loosen the hold-down bolt, and adjust it by turning the distributor. Tighten the hold-down bolt to 13 ft. lbs. (18 Nm), then recheck the ignition timing again.
  2.  
  3. Remove the jumper wire from the DLC1.
  4.  
  5. Check the timing, the reading should now be 213°BTDC at idle. The timing mark will move in this range.
  6.  
  7. Disconnect the timing light from the engine.
  8.  
  9. Disconnect the scan tool.
  10.  

2RZ-FE and 3RZ-FE Engines

Toyota's hand-held tester or an equivalent OBD-II scan tool must be used for this procedure.

  1. Warm the engine to normal operating temperature.
  2.  
  3. Connect an OBD-II compliant scan tool to the DLC3 (Diagnostic Link Connector 3), located under the dash on the driver's side. For additional information, please refer to the following topic(s): Drivability and Emission Controls, Reading Codes.
  4.  
  5. Connect the timing light to the engine.
  6.  
  7. Using SST 09843-18020, or its equivalent jumper wire, connect terminals TE1 and E1 of the DLC1 under the hood.
  8.  



Click image to see an enlarged view

Fig. Using the SST 09843-18020 or a jumper wire, connect terminals TE1 and E1 of the DLC1

  1. After the engine speed is kept at about 1000 rpm for five seconds, check that it returns to idle speed.
  2.  
  3. Check the ignition timing, the reading should be 37°BTDC at idle.
  4.  



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Fig. The timing should be between 37°BTDC at idle

  1. Remove the jumper wire from the DLC1.
  2.  
  3. Recheck the timing, the mark ranges from 718°BTDC at idle.
  4.  
  5. Disconnect the scan tool.
  6.  
  7. Disconnect the timing light.
  8.  

2UZ-FE Engine

Toyota's hand-held tester or an equivalent OBD-II scan tool must be used for this procedure.



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Fig. Clamp the timing light inductive pickup to the wire of the ignition coil connector for No. 1 cylinder and jumper the DLC1 terminals TC and E1 2UZ-FE engine



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Fig. The ignition timing should be 515°BTDC at idle2UZ-FE engine

  1. Warm the engine to normal operating temperature.
  2.  
  3. Connect an OBD-II compliant scan tool to the DLC3, located under the instrument panel on the driver's side. For additional information, please refer to the following topic(s): Drivability and Emission Controls, Reading Codes.
  4.  
  5. Shift the transmission to the N position.
  6.  
  7. Connect the tester probe of a timing light to the wire of the ignition coil connector for No. 1 cylinder.
  8.  
  9. Race the engine speed to 2500 rpm for approximately 90 seconds. Allow the engine speed to return to idle, which should be 650750 rpm.
  10.  
  11. Using SST 09843-18020 or its equivalent jumper wire, connect terminals TC and E1 of the DLC1 under the hood.
  12.  
  13. Using a timing light, check the ignition timing. It should be 515°BTDC at idle.
  14.  

 
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