Land Cruiser, Sequoia & Tundra 4.7L V8
Distributorless Ignition System (DIS) uses Engine Control Module (ECM) for determining ignition timing (spark advance). ECM may determine ignition timing (spark advance) based on various input signals, engine RPM and knock sensor input signals.
Conventional distributor and pick-up coil have been replaced by camshaft position sensor and crankshaft position sensor. Camshaft position sensor and crankshaft position sensor deliver input signals to ECM. ECM detects standard crankshaft position based on camshaft position sensor input signals and actual crankshaft position, and engine speed by crankshaft position sensor input signals. Camshaft position sensor is located behind driver's side upper timing belt cover, near camshaft sprocket. See Figure, Figure and Figure . Crankshaft position sensor is located at front of crankshaft, near crankshaft pulley. See Figure, Figure and Figure . For knock sensor location, see KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
The ECM uses 8 ignition primary control signals to ignitors for ignition coils. DIS uses 8 ignition coils with internal ignitors, one ignition coil for each cylinder. See Fig 1. Cylinder No. 1 is front cylinder on left side of engine when viewed from flywheel end of engine. Cylinder No. 2 is front cylinder on right side of engine when viewed from flywheel end of engine. Cylinders No. 1, 3, 5 and 7 are on left side of engine. Cylinders No. 2, 4, 6 and 8 are on right side of engine. The ECM monitors IGF circuit at ignitor to ensure ignition coils have fired.