Hi, my daughter has an ancient (1991) LT35 6 cyl diesel used as a horsebox, bought a couple of months ago. Its a 2.4 non turbo engine.
It seems well down on power and black smoke up hills under load, we replaced the fuel filter and hoses in the engine bay and the bleed off hoses on the injectors, new air filter etc, but also noticed there is a second fuel filter that appears to be in the return pipe to the tank.... you get to this under the ;passenger side wheel arch.
Cant understand why there would be a filter in the return pipe.
Also a poor starter from cold, new glow plugs fitted but didnt fix the problem. Im just about to put in all new wires back to the relay.

Question 1 - is this the return pipe and does this filter need changing? Or is this some modification someones done in the distant past.
Can't see how that would affect the running.

Question 2 - we have no idea on vehicle history but its condition when we bought it seems to indicate its been stored for quite a while, it is in pretty poor shape and needed quite a bit spent on brakes etc.
Is it likely that the power loss is due to dirty/bad injectors?
If so is it worth getting refurbished or just buy new - I saw a set of 6 new being sold for £180, so it seems a reasonable price.