17mpg from my dirty diesel

[Jammy19]

I guys, I've got a 200tdi, it has big off road wheels & rubber, it's pretty smoky, in its checkerd past it has had some power screwed into it, from a place in Mansfield apparently, you can tell it has abit of grunt but has no real power, especially above 30 ish, I did a 50 mile run yesterday and got about 17mpg, I feel like theres alot of fuel going in and not alot of power coming out, should I be expecting this level of thirstyness or can I get abit more bang for my buck?

[Bowie69]

Sticking brakes?

You should be getting more than that... Especially on a run.

[Chicken Drumstick]

Firstly how are you measuring distance and how are you measuring the fuel used?

Often people with extreme mpg figures, either high or low. Is often explained by an error in how it's being calculated. 

That said big tyres, heavy right foot and over fuelled could easily result in low mpg. 

[monkie]

What do you mean by "had some power screwed into it"? Also when you say it has no real power, what are you comparing it to? It might point to a low boost pressure issue, that could result in a low mpg.

I think the easiest and cheapest thing to look at first is to give it a good service if due (oil change, oil, fuel and air filter - clogged up filters aren't going to help mpg) then take off the intercooler and clean out all the accumulated oil with some petrol (make sure you get all the petrol fumes out before reinstalling the intercooler). While the intercooler is off remove all of the rubber hoses from the turbo, intercooler and inlet manifold and carefully inspect all of them for splits, tears and delamination - a dodgy hose which has split or delaminated can lower the boost pressure - that would account for low mpg and poor performance.

[dave88sw]

Far too many people out there think that just winding out the max fuel screw will give you loads more power.  It's not that simple, you need to match the extra fuel on boost with extra boost by adjusting the wastegate rod.  Otherwise you're just throwing extra fuel in with no gain because you can't get enough air into the cylinder to combust it properly.  Apart from rubbish MPG it's not particularly good for the engine.  If it were mine and i had no idea what had been done in the past i'd take it to a reputable diesel specialist and have the fueling returned to standard.  Then if you really did want a bit of extra power, follow the guide that's on here somewhere, you'll need some way of measuring boost pressure and ideally exhaust gas temperature.

[FridgeFreezer]

What dave88sw said - all you can be sure of is someone's dicked about with it, get it put back as it should be and go from there.

[Cornish Rattler]

On 11/15/2016 at 7:42 PM, Jammy19 said:

I guys, I've got a 200tdi, it has big off road wheels & rubber, it's pretty smoky, in its checkerd past it has had some power screwed into it, from a place in Mansfield apparently, you can tell it has abit of grunt but has no real power, especially above 30 ish, I did a 50 mile run yesterday and got about 17mpg, I feel like theres alot of fuel going in and not alot of power coming out, should I be expecting this level of thirstyness or can I get abit more bang for my buck?

Mine went like that ( 2.5td with a Def 200tdi fitted ) as the FIP had been tweaked to max and possibly the turbo aswell the engine had loads of power but down to 18mpg on runs like you big tyres but think it was more the FIP and inj's getting tired, took the engine out to fit a Disco 200tdi engine not quite as powerfull but 32mpg.

The old Def 200tdi is going into the s11a project we are doing so will get the FIP and inj's done for then aswell as a recon'd turbo as its pretty worn

Edited November 18, 2016 by V8 Freak
Corrected quote / response formatting