Planning this month's car budget.

I'm still getting to know the car and am trying to remedy some hard starting/nailing/smoke issues. After a Diesel Purge, some slight nailing goes away after about a minute of idling when cold. Some minor shaking also disappears. Still have some white smoke at cold idle and black smoke when I floor it.

To date I've:

1. Adjusted the valves (and then again to double check that I did it correctly).

2. Performed two compression tests (either 320 or 290, all pistons, depending on which Harbor Freight quality gauge you trust).

3. Drained tank and checked mesh filter.

4. Diesel purge, remove muck from the secondary filter housing, replaced both filters. Car sounded and idled very, very smooth while on the Purge. Also had more power afterwards.

5. Have continuity across all glow plugs.

6. Not a real check from what I've read, but the timing chain/pedestal mark correspond to TDC on the balancer.

7. Maybe related to the root cause of my problem: primary filter only half full. 100% full while sucking from my Purge tank.

Anyway, the PO replaced the injectors with Bosch one year ago. So I'm thinking about going the cheaper route first and buying the drip tube and 90 degree wrench to check the injector timing first. That being said, why the marked improvement with Diesel Purge if the injectors are fairly new?

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1974 240D "Boldie" 170K.- New timing chain/freshly rebuilt IP/replaced valve seals/injectors/upgraded stereo/new Bilsteins with Yokohamas/fresh paint and rocker panels plus lots of welds.