My own car started of as 1900td and was bog standard one owner car when I got it. Unthoughtionately for me mine was the unwelt 1900cc wich means it has the eco pump, unthoughtionate as this pump has no boost pin so its not so tunable. If your pump looks like this one below change it if you can, Im actually using the bottom half of that pump with the top half from a normal 1900td pump
As we have a picture of the eco pump up I will tell you what you can do to this to make your car a little qicker. facing the engine on the top of the pump LHS so oposite side to the flat top where a normal pump has the boost pin you will see a metal cover held on by if I remember 3 or 4 small allun key bolts. If you remove this junk it and will find an adjustable cam/ switch. This switch tell the turbo at what revs to cut in so by adjusting it you can get the turbo to kick in at lower revs, you can just remove it, on mine I bent the part of the switch over so it kick in earlier but not all the while, sure if you remove the said cover it will become straight forward and I will add a link from another forum how to do it. Only over thing you can do is to turn the fueling up and the tick over down like you can on any pump and you can't just swap the flat top over for one with a boost pin as the eco pump is blocked off underneath
Heres a picture of a pump with a boost pin, its from a B4 and this one has also got that switch for the turbo on and you can see the adjustment slot on top, but you would want to adjust more that you can with the cover on, Lee will probably recognise that engine. Appears not all 1900td pumps have that switch because mine dose not
If you have the normal pump that runs on boost you need to swap the pin for the 1600td one if you have a 1900td as they have a totally different profile, you can also use a rover 217 boost pin and I have heard of people taking an angle grinder to there own pin, you will find the pin you need on e-bay as its a very common mod. There are other mods that can be done to both pumps but that involves pulling them apart and they are pretty complicated.
Next mod which is another that cost nothing is removed ERG valve, thats the shinny pipe you see below
Junk it and this will stop the turbo sucking in dirty hot spotty exhaust fumes and make your engine rev up quicker
I just used to bits of scrap tin to do mine
Fit a good quality cone filter, think its a 52mm neck one you want, I have K&N, cost more than standard but you never have to buy another. You need to fit the cone as far away from the engine as you can so it draws in cold air.
For this I used the rubber hose from a Ford Mondeo air box. Paid £2 from the local breaker and only had to cut it down a little
I then to get cold air in to the engine bay and directly to the filter made an air scoop by shaving the indicator, not noticeable unless you know its there
Time for a cuppa