BrierS,

Do you use synthetic oil in your engine? Its been said here that using synthetic oil, preferable Mobil 1 or Delvac 1, in a 603 series engines will quite valve lifter noise.

The ALDA is the device that causes more fuel to be injected into the engine when it gets turbo boost. If extra fuel isn't injected there will be no power gain from the turbo increasing the manifold pressure. The ALDA also regulates the fuel input depending on the altitude.

The ALDA sits on top of the injection pump and is connected to the intake manifold by a small vacuum or pressure tube similar to the vacuum lines.

P E H