Fuel consumption on V8i Auto

[mosslman]

Now I was ready for the shock but after several tank fulls I am struggling to get below 20l/100km. Is this normal? I have been slowly fixing it up ready for a 2 month tour since he had been a bit neglected before we found him. It has had Bosch ignition fitted and runs pretty smoothly although on idle it can hunt a bit, it also can run quite hot when pushed up long hills but I suspect the radiator is in need of clean/replace which I will be doing later. I did at one point find mention of a pdf describing the voltages for the maf and tps sensors but can't find it again, does anyone know where it is?

All suggestions welcome!

Sandy

[sparky34]

That is about what i get around town, and about 14 highway driving if i stick to 100 klms. they are thirst buggers.

[mosslman]

Oh well, lucky I am only using it for trips and not daily commuting! most of the driving has been either short trips around town or a couple of outings, Scenic Rim, including Duck Creek and Condamine River tracks, and a weekend sand driving on Straddie, had a great time, just got to pay for it I suppose!

Cheers
Sandy

[SMASH]

That is about what i get around town, and about 14 highway driving if i stick to 100 klms. they are thirst buggers.

How do you get 14? i get about 18-19 on the highway on fuel and 21 ish on LPG

[Chops]

Not sure what it equates to in Lts/100, but the best I've ever had from mine was a total of 440k's from a tank, but consistantly got around the 400k's sitting on or just above the speed limits between Melb/Albury. That was using Caltex 95Ron.
In traffic - Melb - lucky to get around the 350 mark,, usually 320, but I have a lead foot,, :twisted:
These machines are'nt good on fuel, but you can help them by how you drive, tyre pressures, weight carried onboard etc.

[mosslman]

Well, the manual claims the tank holds 89 "usable" litres so 440km is pretty close to 20l/100km assuming you were running on fumes at the end! never been that brave yet. I suppose the other question is what type of petrol do people use? I have steered clear of the E10 but have only used 91 ron. Is it worth paying more for 95? do you get more than the cost back in extra mileage due the higher energy?

Sandy.

[Chops]

I did a trip from Albury to Fraser Island towing a boat, and on the way up we discovered that using the higher octane fuel was better all round. It gave me noticably, more power, and better economy (as in, more K's per tank). To stay on or around the speed limits, I had to use less right foot, we stayed with the traffic with ease, without labouring the car, especially going up hills. I noticed a much reduced "pinging" as we travelled too. Thus, from then on, I have always used the 95R.

Chops

[mosslman]

Interesting, I will definitely try it out, particularly since it is getting harder to find 91R without Ethanol added. Mine is the low compression 3.9 btw.

Sandy

[Gary S11]

Hi, how do you tell if your 3.9 is high or. Low comp, ? Gary

[bee utey]

Hi, how do you tell if your 3.9 is high or. Low comp, ? Gary

Usually says so next to the dipstick where the engine number is, unless its been rebuilt with other than stock pistons.

[mosslman]

Hmm, good point, mine has CR 8.13:1 stamped but as you say who knows what has been done during its 300k life! I suppose the only way you would know is by taking the head off, or perhaps a compression test would be accurate enough to tell?

[Rupert Prior]

they do like to drink, but with careful set up you should be able to get 15's and possibly 14's per 100km (not around town)
some things to check
general engine condition, (plugs, leads, filters, breathers etc)
cooling system, especially thermostat (88deg) and viscous fan
ignition settings, (mech' advance, vac' advance, dwell, coil type)
battery, earths and charging
fuel pressure
base injection settings (throttle pot etc)

they seem like a nice simple system, but small changes in one part produce big changes in a seemingly unrelated area.

[sparky34]

How do you get 14? i get about 18-19 on the highway on fuel and 21 ish on LPG

I can get that if i use 95 oct fuel drive between 90 and 100klms, all highway driving, only 1 person in the vehicle, tyres pumped up and drive like an old grandmother. I have a 96 Disco with 103000klms on the clock and it is in good tune. At 110 and cruise on its 20+ easy.

[101RRS]

I regularly got 13.5-14l/100km cruising on the highway at 110kph with a/c on using 91 Ron. Around town I used to get 17.5-18l/100km. The 3.9 can be economical for what it is with normal driving - however drive foot to the floor, hard on the brakes etc and fuel consumption will sky rocket.

Garry

[mosslman]

13.5l/100km with a/c at 110km, would be brilliant, any tips on how you got that? I drive pretty gently these days.

Sandy

[101RRS]

13.5l/100km with a/c at 110km, would be brilliant, any tips on how you got that? I drive pretty gently these days.

Sandy

Drive normally - I maintained my vehicle as it should have been - I had it for 12 years and covered 110,000km and recorded fuel consumption for the whole period. Driving Canberra to Newcastle and regularly averaged 14 - best 13.5. Used cruise on most of the flat bits - off where in up hilly areas.

Use the loud pedal unnecessarily and you are in 20l/100km territory.

It is not difficult to get good fuel consumption but equally it is not difficult to get bad fuel consumption - you don't need to drive like a pussy but you do need to drive smart.

Garry

[mosslman]

Oh well, something to aim for! but did you note an increase in consumption (I keep wanting to say mpg!) as the km's rolled by?

Sandy

[SPROVER]

I did a trip to QLD from VIC and back in 2010 and i recorded all my fuel consumption.My Disco was fully loaded with camping gear,recovery equipment,tools,clothes spare parts.It was running 265/75/16 muddies with lift, bull bar, winch,steering guard,long range fuel tank,heavy duty rock sliders and 60 litre LPG tanks.So its not a light car.The best i recorded was 15.8 litres per 100 km.But that was only on 1 occassion.The other times it was a steady 17.3 litres per 100km.I was happy enough with that for a 3.9 V8and 200 000km on the clock.Around town its a different story though.With just me in the car and running the muddies it was 21 litres per 100km.:D

[101RRS]

Oh well, something to aim for! but did you note an increase in consumption (I keep wanting to say mpg!) as the km's rolled by?

Sandy

Not really - but towing does knock it around.

[Rick1970]

The missus's '95 V8/auto Disco (250000Km) averages at 15.5-16L/100km, combined town, rural tar road and dirt driving (home to work, 100km a day). 2" lift 245/75 16 AT's 95 RON fuel and her driving it, rather hard sometimes :p

My '86 3.5 manual Rangie (510000Km) averages at around 13.5L/100 doing the same, but has got as low as 12.2L/100 if i'm content to sit on 95 rather than 105ish. Flog it hard and it drops at an alarming rate.

Big boot usually equals big fuel bill.

[theg]

On wednesday I drove the Pacific Highway from Newcastle to Brisbane .
My 89 rangie has a very good stock 3.5 efi and I run it on 98 premium .
Fuelled up at 480klms with exactly 60 litres = 8klms per litre = 12.5 litres per 100klms .
Car has rear seat removed and no floor coverings just 2 mats .
Has a ARB bull bar . Apart from that shes standard . 4 speed auto with viscous tfer .
Note : This is on 98 octane and driving at speed limit mostly 100kph with 110 stretches .
Note II : I have my ignition timing wound up to 11 degrees at idle ( makes an enormous difference to light throttle highway driving)