Poor fuel consumption

[landiematt]

Hi all
4bd1 N/A lt95 box.
Poor fuel consumption compaired to others I have heard of.
average of 14.5lts per 100.
I do all high way kms at 100 kph. Have replaced all filters and replaced screen.
I run inner and outer air filters. Doesn't appear to blow much black smoke .
I can't work out why it would be so high compaired to others on here and those I know.
Any ideas?

Matt

[grey_ghost]

Hi Matt,

Silly question time (from me that is).

Have you:
checked that your tyre pressures are set to highway speeds?
checked that your rear (drum) brakes are adjusted?
checked that your hand brake is adjusted correctly?
Checked the wheel bearings?
Replaced/checked your diff oils?
General service - oil, filters, etc?
Do you have anything like a roof rack?
Larger tyres?

I have a stock FFR - and running at 100kmh, I get around 10-11.5

14.5 is higher than I would expect but I also get 25-28 in my 101 so 14.5 ain’t bad! [emoji6]

Cheers,
GG

[landiematt]

Hi GG

Front and rear diff out of 97 defender so disc all round
not sure about hand brake. Will need to check.
Car has been back on the road for a year. All oils done back then. Engine done every 5000 since.
Wheel bearing were good but will recheck.
Tyres at 45 psi front 50 rear .
32 11.5.15 tyres. So a little big but same rolling as standard. Give or take .

Matt

[landiematt]

Sorry do have a box and roof top tent on it

[weeds]

Is the speedo correct??

[landiematt]

No it appears to be 10 out so I been doing 100 on gps unit speed.
Not sure if that's correct thing to do or not.
Speedo says 110 kph when gps says 100

[Red90]

Also check the odometer reading. They are usually not out as much as the speedo.

Beyond that aerodynamics is the big thing. Lift. Rack. RTT.

Mine does between 10 and 11 and weighs over 3 tonnes. Drive at 110 all the time.

[landiematt]

I do work it out by the odometer (maybe incorrectly).
I don't try to take 10 percent off kms.
Maybe I should try to work out the kms more accurately.
Even still taking off 10 percent I am not down as low as others.
10's and 12's are dream numbers for me at the moment.[biggrin]
Matt

[Bearman]

Might be worth getting the injectors checked. I am wondering if it may have turbo injectors in it.

[rangieman]

Sorry do have a box and roof top tent on it
This here my friend will be your major contributor to poor economy figures [wink11]

[DeeJay]

It wouldn't hurt to remove the inner filter. They are intended for heavy duty environment. I ran the 3 Isuzu's I've owned over the years without them.

[landiematt]

Hi all.
I am going to remove box and tent. And inner air filter and start from a level playing field and see where I end up and start back from there.
Hopefully better fuel and see what's doing the big damage if anything.
Matt

[Blknight.aus]

Hi all.
I am going to remove box and tent. And inner air filter and start from a level playing field and see where I end up and start back from there.
Hopefully better fuel and see what's doing the big damage if anything.
Matt

Leave the inner filter alone.. if its got dust.on it change it and the outer