I've never worked on a 1hdt so you can take this for what it's worth. After checking the grounds and charging system my next move would be glow plugs as they generally use quite a bit of amperage and could cause that type of spark and smoke if a pinched or bare wire grounded on the chassis...
Hey everyone, This is my first post on here. A few weeks ago picked up a locked 96 landcruiser from the original owner and it has 161k miles on it. I haven't driven it yet as it was in storage for the last four yrs. At 90k the PO installed a safari turbo and a few other supporting engine mods...