Paul, my 4BD1 used to blow a fair bit of black smoke cruising on the hwy. In June I dragged a 3ton trailer for 2,600km from Derby to Alice ... heaps of black smoke and I had to wring everything I could out of the old oiler (370,00km). From Kununurra onward I started adding Nulon Injector Cleaner to the fuel and by the time I got to Tenant Creek it was roaring along beautifully with very little grey smoke and pulling the load comfortably. It now runs well with a little bit of grey smoke under hard acceleration. I put the big improvement down to two things; a) the injectors needed cleaning and b) I reckon the cyclinders may have been a little glazed from years of light work pulling a 110 instead of a loaded truck. The really hard work for 6 days straight clearly sorted that out.
This Xmas I'm doing another trailer trip, this time ASP to Adelaide and will bung in some Nulon again. From Adel to Vic high country and back I will be running home brew bio-diesel, so I will be really interested to see how that goes.
Personally, I think the 4BD1 doesn't slog hard enough in a 110 to keep it happy. Mine spent many years of its early life with the original owner dragging horse trailers and that probably a good thing. A better fit for the vehicle weight would be the later 4BE1 (3.1lt I think).
JohnS (khunmoo)

