Fuel Ecomomy Not

[Gardiner]

Ok so the SJ is back on the road and I'm sure I have another issue.
I have worked out without thrashing just pottering around No off-roading this time and I'm getting 11MPG !! Gulp. I may as well get a V8 Landrover.

So I have the following.
1.3 with a Rockwatt Manifold and SU Carb All new needle and spring seals etc etc
Brand New Custom Petrol Tank and Petrol pipes so NO leaks
Just MOT'ed with great emission's and the plugs are lovely colour.

But 11MPG seems a bit excessive what is everyone's thoughts !!!

[ScottieJ]

What size tyres are you running? The speedo might be out and messing up your calculations.

[Gardiner]

Cheers for reply I'm running 205x16 on Landrover rims and to be honest I have done 21 miles which is about right if anything slightly higher I would say lol and I put 8.5l in it. I might be doing her a slight in justice as I may have filled it a bit more than last time give or take half a litre.

[ScottieJ]

205x16 are around 29” tall aren’t they so you you would have done more distance than the clocks say. Around 10% more

The best way to work it out is to fill the tank and 0 the the clocks. Then next time you fill it up take a note of how much it took to refill. you’ll have a more accurate distance and fuel consumption figures to work it out from (remember to add 10% to mileage)

Sj fuel gauges are pretty vague so there could actually be 5l or so difference in how much fuel is in the tank near the bottom of the gauge/tank and it’ll look like it hasn’t moved.

However I’m not sure how you have been working it out but it should easily see 20+mpg, usually 25-28mpg with the 1.3

[donkeychomp]

And after that and you still seem to get 11mpg I'd check for fuel leaks. Actually, I'd do that first! My old 413 was getting awful mpg until I found out the fuel pipe had split...

[Gardiner]

Cheers for reply's
I now have a custom Aluminium fuel tank in boot with a sight gauge and no proper fuel gauge.
All Fuel pipes have been replaced with heavy duty rubber hoses front to back.
So on the assumption of 10% higher that means it has done 22 miles on 8l of petrol.
What are the 1.6 engines like on fuel ???

[ScottieJ]

The 1.6 8v is practically the same engine and no different on fuel.

16v mpfi is better.

Still there is a problem somewhere if you are actually only getting 11mpg. My sj has a 1.6 on an SU, two transfer boxes and runs 31 or 33" tyres and still sees low to mid 20s

I would double and triple check for fuel leaks, maybe check the fuel overflow on the SU carb isn't throwing fuel out because of a sticking float or anything like that.

[zook123]

I was putting £15 in the tank, and it would go to above the halfway mark and I was getting around 21MPG, after calculating that half a tank (20l) would cost £24, I filled it and it was showing 3/4... but lasted 135 miles which brings it to around 30mpg..

Don't go on the fuel guage as theres a "reserve" tank on the Jimny of around 10miles after the red!!

[ScottieJ]

He hasn’t got a stock tank read his last reply

Also there isn’t a reserve tank, it’s just the shape of the tank and how the level sender works. It isn’t a linear relation between fuel qty and the gauge reading.

[SherwoodNash]

and....he hasn’t got a Jimny read his first reply