50mpg from 1.4TDI90 on long trip - normal?

First proper run today of over 100 miles - I just ticked over to 55mpg briefly, which I’m fairly pleased with considering I have a lot of issues with the car, not least buckled 17” alloys and a leaking flexi (more gushing than leaking?). Looking forward to putting 15 or 16’s on, a remap and some aero mods to increase mpg. Of course the accuracy of the DIS may not be the best……
 

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It should be better than 50???? my 1.6 does 47/48/49/50 and I do not drive like Miss Daisy….. the deciding factor being traffic? As I am usually stuck at 70mph
 
First proper run today of over 100 miles - I just ticked over to 55mpg briefly, which I’m fairly pleased with considering I have a lot of issues with the car, not least buckled 17” alloys and a leaking flexi (more gushing than leaking?). Looking forward to putting 15 or 16’s on, a remap and some aero mods to increase mpg. Of course the accuracy of the DIS may not be the best……
Thats a good start, MPG depends on so much you cant compare, I drive with no air con (broken), mainly motorway at 70-85MPH fairly flat with one hill, every day out and back 70 miles in total and get 59.9mpg average, but my car has been recently serviced all through with new ish 17 tyres. Its a tdi 90 with 140k and new turbo to boot. cant seem to get any higher unless i go 64mph everywhere. I get about 46-48 at 80mph
 
I get around 60mpg in both my TDi90s cruising at 67-70mph.

DIS consistently tells me I’m averaging low 50s in both cars however, strangely
 
The only real issue I’m having with it is cold starting, takes 2 - 3 turns of the key and some gas to get it going but not everyday, maybe injectors are still a bit clogged. Confident the head gasket is ok, I gave it a good blast for about 25 minutes at 80 - 85mph (on my private runway) this morning and floored it briefly in 4th on an incline to over 3500rpm, so hopefully it makes a difference. Really smooth at those speeds too, no wobble or shaking at all. By the end of the journey MPG had dropped by 2.5, which to me is not bad at all.

60mpg is the gold standard for me. Need to calculate actual consumption when fuel is low again.
 
If yours is a 75 as per your profile then you should get 60mpg easily at the same speeds I do, perhaps even slightly better.
 
The only real issue I’m having with it is cold starting, takes 2 - 3 turns of the key and some gas to get it going but not everyday, maybe injectors are still a bit clogged. Confident the head gasket is ok, I gave it a good blast for about 25 minutes at 80 - 85mph (on my private runway) this morning and floored it briefly in 4th on an incline to over 3500rpm, so hopefully it makes a difference. Really smooth at those speeds too, no wobble or shaking at all. By the end of the journey MPG had dropped by 2.5, which to me is not bad at all.

60mpg is the gold standard for me. Need to calculate actual consumption when fuel is low again.
Youll get there in the end. Cold starting could be a few things, glow plugs battery fuel filter, leak back from injectors etc. You'll have to check each one at a time. If your running turbo cleaner try and 'load' the turbo and low revs this will move the vanes open and closed more without too much soot which you get if you rev it lots. The soot is what you want to avoid. Revving high for long time is good for injector cleaning though I found.
 
Got to over 480 miles before the yellow light came on during a return trip from Kent to Leeds. I read somewhere that there is a feature on the pump that sucks back fuel if you overfill, so I never brim the tank. Does this light turn red at any point?
I sit with the lorries. I expect I have used about 6 gallons.
 
I managed almost 850 km before the light came on yesterday. Also got 64 mpg driving from Reading back to Canterbury.
 
IIRC my manual says that the DIS average MPG is for the last 35 miles.
I did roughly 40 miles today and the mpg barely moved from 52. Maybe 0.2 deviation across the entire journey. I always assumed it was the whole trip journey that mpg was calculated on, so that’s an eye opener for me. Is there a better way to calculate real average mpg, other than just taking note of where the needle is at fill up, how many gallons you put in and resetting the trip?
 
You can reset the average fuel consumption and speed measurements - it is not correct that they are based on the last 35 miles.
 
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