300 tdi discovery 20MPG :/ HELP!!!

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Dicovery maniac

New Member
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225
Location
Dewsbury
i have a 300 tdi comercial discovery which has had a few things done to it which would put mpg down a bit but not by this much should average at least 27mpg and i am getting around 20mpg is there a common fault somewhere been like this for a while, also had new head gasket. cylinder head (new not skimmed) and rocker shaft but was doing terrible mpg before this aswell can anyone help
 
you want economy get a car.

a 300tdi manual will get around 30-35mpg and auto around 25mpg as standard.

fit bigger and more aggresive/mud tyres, roof racks etc. and you can very easily knock another 5mpg off
 
i dont want economy i just want my car to do right by what you are sying im loosing 10 ive seen a couple of land rover garages todai and they said that it is too thirsty for what it is
 
Dicovery maniac said:
i dont want economy i just want my car to do right by what you are sying im loosing 10 ive seen a couple of land rover garages todai and they said that it is too thirsty for what it is
Click to expand...

Has it been lifted?

What tyres are you running on?

Has it been serviced regularly?

Has it got a roofrack?

Do you carry a lot of stuff in it?

What's your driving style?

all these factors and many more can reduce mpg a little, so combined they can reduce it a lot.
 
Had similar problem.

I mainly do motorway mileage, and average 450 - 500 miles a week. My Disco started drinking diesel like it was going out of fashion. Everyone was stumped, as the engine was / is great. Turned out to be, the dodgy garage who did MoT work on it a few weeks previous, had altered the wheel angles (castor I believe). So much so that the first thing I noticed was tyre wear to the inside tyres on the front wheels. They where effectively facing inwards. This mean't I had to put me foot further down, to get the same speed...and drink more fuel than was necessary.

Sorted them and that improved things dramatically...back to 25 - 28MPG now.

Cheers
 
yeh its lifted 2" and 235/85/16 grabber at2 and has a few lights and a rubber bull bar but not too much wait inside it and i never keep the roof rack on and i no these all have factors on it but dont think whats on it would do it this much.
i am having new wheels on it this weekend so i will have it checked for the caster etc. i have alot of play in my steering wheel i know about that and am on my way to fixing it.
i check the pressure oftenly and keep them at 32 psi
i did discover todai that my final injector wasnt blocked off so i believe this could of been leaking diesel so i have fashioned a blocker on to it
 
MW1LCR said:
Had similar problem.

I mainly do motorway mileage, and average 450 - 500 miles a week. My Disco started drinking diesel like it was going out of fashion. Everyone was stumped, as the engine was / is great. Turned out to be, the dodgy garage who did MoT work on it a few weeks previous, had altered the wheel angles (castor I believe). So much so that the first thing I noticed was tyre wear to the inside tyres on the front wheels. They where effectively facing inwards. This mean't I had to put me foot further down, to get the same speed...and drink more fuel than was necessary.

Sorted them and that improved things dramatically...back to 25 - 28MPG now.

Cheers
Click to expand...
tracking,castor is angle as in motor bike forks and can only be altered by rotating axle
 
Dicovery maniac said:
yeh its lifted 2" and 235/85/16 grabber at2 and has a few lights and a rubber bull bar but not too much wait inside it and i never keep the roof rack on and i no these all have factors on it but dont think whats on it would do it this much.
i am having new wheels on it this weekend so i will have it checked for the caster etc. i have alot of play in my steering wheel i know about that and am on my way to fixing it.
i check the pressure oftenly and keep them at 32 psi
i did discover todai that my final injector wasnt blocked off so i believe this could of been leaking diesel so i have fashioned a blocker on to it
Click to expand...
the leak off fitting on no4 injector is blocked off internally it just looks like somethings missing
 
Two reasons for using lots of fuel apart from the 2 inch lift and the big tyres, would be a bad leak which you would see and smell or it's burning to much fuel which would give you lots of black smoke, simple as that.
Adjust the maximum fuel/power screw and reduce the smoke and also improve the fuel consumption.
 
also dont wanna start messing with the fuel pump when its already in its original position but i used to get alot of black smoke before i had the new head and head gasket but its not as bad now
 
Dicovery maniac said:
also dont wanna start messing with the fuel pump when its already in its original position but i used to get alot of black smoke before i had the new head and head gasket but its not as bad now
Click to expand...

It should not be bad full stop,black smoke is excess fuel and that's where your fuels going.
 
If your pump has not been messed with then your not getting enough air and then you would have also mention that the performance was bad.
 
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