The need to bring the piston (to her) to the TDC position occurs during many procedures, in particular, when adjusting the valve timing, replacing timing drive components, etc.
1. Make sure the transmission is in neutral and apply the parking brake firmly, or chock the rear wheels of the vehicle. On a gasoline engine, also turn off the ignition system by disconnecting the electrical connectors of the primary (HB) contour (smaller wires) coil assemblies (see chapter Engine electrical equipment). Remove the key from the ignition lock. Turn out the candles (see chapter Vehicle settings and routine maintenance).
2. Bringing any of the pistons to the TDC position is carried out by turning the engine crankshaft in one of the ways described below. Looking at the engine from the front (from the timing drive), clockwise rotation of the crankshaft will be considered normal.
- The most effective method is to rotate the shaft in the normal direction (never try to turn the shaft in the opposite direction!) for a bolt screwed into the end of its front trunnion using a socket wrench with a ratchet drive.
Note. On some models, this requires removing the lower protective screen on the front passenger side.
- Save time by using the remote control for the operation of the starter (follow the manufacturer's instructions). As soon as the piston is close enough to the TDC of the end of the compression stroke, the starter stops and further adjustment is carried out by the method described in paragraph a;
- If there is an assistant, the preliminary cranking of the engine can be carried out by short engagements of the starter from the driver's seat under the guidance of the operator. The principle is the same as described in point b. The final adjustment, again, is done manually, using a socket wrench (see point a).
3. On the 2UZ-FE gasoline engine, the ignition distribution is controlled by the on-board processor through coil assemblies installed above each candle (see chapter Engine electrical equipment).
4. To bring the engine to the TDC position, unscrew the spark plug of the first cylinder and screw a compression gauge in its place; you will need a threaded nozzle with a connecting hose at least 15 centimeters long (see chapter Engine).
5. Start turning the crankshaft at the pulley bolt in the normal direction (see paragraph 2). The approach of the piston to the TDC position of the end of the compression stroke is accompanied by a rise in pressure in the cylinder. Continue turning the shaft until the alignment marks line up (refer to accompanying illustration), with random «slipping» TDC position, depressurize the gauge and rotate the shaft two more full turns!
6. The guarantee of bringing the engine to the TDC position of the end of the compression stroke of the piston of the first cylinder is the adequate alignment of the alignment marks on the sprockets of the crankshaft and camshafts.
7. Now, to take turns, in ignition order (see Specifications), to bring the pistons of the remaining cylinders to TDC, it is enough simply to sequentially turn the crankshaft in the normal direction with a step:
- On 2UZ-FE engines - 180°;
- On 1HD-FTE engines - 360°.