It's not oil...wrong color. Maybe this is a draggy turbo or a stuck ALDA?

It could also be one really leaky injector too. This is what I'm thinking is the problem.

IMHO, 8 psi boost sounds a little on the light side. At full chat, a 617.952 should be making a shade over 10 psi but that doesn't seem like it should make enough difference to create clouds of black fuel smoke

Questions...
How's the idle and starting?

Any noise, nailing, clatter?

On a long incline with the engine speed stabilized above 3000rpm, is there a constant black smoke trail?

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