Om646 Engine: Mercedes Workshop Manual

Unlike older mechanical pumps, the OM646’s CP1 or CP3 pump must be timed electronically, but its sprocket is mechanical. The workshop manual provides the exact offset angle and locking pin position (Pump sprocket: 12 Nm + 25°).

This section is vital given the complexity of diesel injection. Mercedes Workshop Manual Om646 Engine

You guess the TDC (Top Dead Center), loosen the camshaft sprocket, and hope for the best. Result: Pistons hit valves. Repair cost: $5,000+. Unlike older mechanical pumps, the OM646’s CP1 or