Hi!
First of i got a 1.6TD engine, witch one i'm not sure, my diesel pumpe does not have this "ufo" at the top, but i got a electric pump between the filter and mechanical pump. Hope this helps?
Well first, my pump is original (not tuned) and my turbo goes 0.65bar to 0.7 depens og witch gear but i'm not happy about my mpg if i calculated correctly witch i'm not 100% sure of, i came to 37,33 mpg(US)or 0.625 per liter pr 10km for mixed driving, people told me i can make it go like 0.4 liter per 10 km so i'm thinking i need to adjust something? Why i think that? Read further down.
This is my first diesel car, but i got experience to petrol cars so modifications might not be a problem for me.
Whats your mpg and with what mods/hp?
There is a problem when i drive on the highway, 5 gear 100+ km/h and coming down a maybe long hill/slope i give less throttle then after a few sec the engine does not go clean and starts to spit out white smoke not constantly but when the engine cough i can see white smoke maybe a little blueish not black, it does not use water so i bet its unburned diesel? What can cause this? I hope my explenation is good enough english is not my native language as you might see.
if someone installed an electric lift pump, then that is good, but they probably did it because the pump was sucking in air from a bad seal. that pump might just be covering up another issue. if not then be happy as it makes changing filters a breeze!
your pump is definitely eco if there is no spaceship on top... but on the vw buses they had an LDA that was on its side although i doubt you have that.
at this stage, the turbo is merely giving you a more efficient burn at the higher rpm's, and is not really affecting mileage except maybe in town where it takes that little extra pedal or 'lag' to spool up the turbo.
best way to increase mpg is to change all 4 wheel bearings, get new tie rod ends & get a 4 wheel alignment, check tire wear and replace bad tires, balance tires if needed, and i think 40 psi is a general consensus for best mileage, but can increase i think it's called 'cupping'??? (on certain tires) if your tranny is geared lower (higher rpm's on the highway) that can decrease economy as well. my setup gives me 100km/h @ 3000 rpm or so, which is convenient because i do not need to shift into 4th going up hills, but for mileage sake i wouldn't mind shifting...
if you do not know the history of this engine, you may want to look into getting the injectors re-built (either new nozzles, or the full rebuild being pressure tested and calibrated) as bad injectors can give smoke as you describe, or even worse, damage your engine.
but for now, the simplest first. as mentioned above, check your timing. that is the most likely scenario.
you should also post your location, and what vehicle you drive... do you use any additives? i notice a power increase when i use power service diesel fuel conditioner. it boosts the cetane number which helps the diesel burn a little bit better and completely, and also lubricates the pump, and is also an anti-gel.