Hello 'Fugly09', my first impressions are that you're a bit of a t w a t, but none the less, I will be a gentleman and lend you some invaluable advice - invaluable, meaning useful not worthless:
Welcome to Landyzone. You have a 2.5TD 19J engine, an engine which is typically acclaimed as being the worst engine that land rover ever produced, but which isn't necessarily true. In it's simplest terms, it was a mere attempt to push land rovers forwards and boost sales, the word 'TURBO' being the real deal sealer (form most consumers anyway) and a so called innovation for Land Rover diesel engines. Wrong. What it is in practice is a 12J engine (AKA 2.5 N/A) with a turbo slapped on the side which the mass typically mis-understood for being a racing car engine, as as such a lot of 19J engines have been over worked to try and meet the expectations of the driver. You will also find a slightly different Lucas/CAV injection pump to that on the N/A, yours having a boost diaphragm to adjust the fueling in correspondence with turbo boost. From day one the engine proved to be very unreliable, with problems ranging from over fueling and over heating, to oil being forced into the air intake causing the engines to rev so hard that they basically ingested their own bollocks. In later years i.e. towards the end of the 80's and the early 90's Land Rover re-enforced the cast iron block and opened out the cooling ports in an attempt to make the engine a little more reliable, which in some respects worked, but in general; the engines still tended to wear out quickly and start developing breathing problems and this is most commonly the case regardless of which 19J you have.
From what you're describing, it sounds like a typical symptom of 19J ownership, but if you do the right things to it, you will get relatively good results, and the smoke can almost certainly be reduced, if not eradicated. Try the following steps for fueling adjustment:
1) Ignore fuel pump timing for now, this can be dealt with later.
2) Start the engine and allow it to run up to operating temperature.
3) Feel down the side of the injection pump (the side facing the engine block)
4) You should feel a long bolt sticking out from the side of the pump (This is the Fueling Adjuster / Smoke Adjuster)
5) Loosen the lock nut and then wind this bolt in one complete turn at a time, tightening the lock nut every time you do so.
6) After each progression, check the exhaust at tickover for black smoke.
7) Eventually, after it's been wound in a bit, the smoke will stop.
At this point, you have reached an acceptable level of fueling for your engine, but you're not finished yet. Have your misses or your boyfriend (as I'm guessing you have) deck the accelerator to the floor and hold it there for ten seconds whilst you observe the exhaust for smoke. Generally speaking, the fueling is 'spot on' when there is a constant whisp of black smoke visible from the exhaust. There should not be clouds of smoke, perhaps a blast when it is revved up, but then it should reduce to a constant whisp. That's the fueling sorted. Chances are that a previous owner has adjusted the pump so that it has extra fuel for extra power. In principle this should work, but in practice it just wastes fuel and produces smoke as opposed to power which is actually reducing performance, not improving it.
Next step is solving the misfire. First thing first is to develop and understanding of the mechanics of the engine. It's a diesel, so there are no spark plugs to play up and no electronic ignition to start wearing out or degrading. The problems lay in the compressions in the cylinders and the fueling to the cylinders. Does it only misfire when it's ticking over or when the engine isn't at operating temperature? This is typical behavior until the engine has reached a temperature of 86 degrees C or there abouts, at which it should be starting to smooth out a little. Heat plays a major role in the compression and combustion of diesel and generally speaking the hotter the engine, the better it will run (obviously over heating being an exception to the rule). If it still misfires at operating temperature there are two possible causes:
1) Compression loss, either by a means of cracked piston crowns, a split block, worn rings or a blown head gasket
2) Fueling problems, primarily air in the fuel
The first step is to bleed the fuel system and see if this helps. Run the engine for five minutes after it has reached operating temperature and then switch it off. Observe the top of the injection pump and you should see a nut just below and to the right of number '10' in the picture below
Loosen this nut slightly and then re-start the engine. If there is any air in the system, as a rim of fuel appears around the seam of the nut bubbles should appear. If the fuel runs through the pump bubble free, there isn't air getting into the system and you need to start considering getting into the engine to examine the piston crowns, the state of the head and the bores for wear etc.
-Pos
