I know the whole fuel consumption issue is getting discussed to death, but my car's fuel consumption has really been bugging me, and I can't think of what to do next. I also decided against posting it in Lugo's thread, since I didn't want to derail it with all this stuff specific to my car.

I have a 2001 TJ VR-X, 5 speed tiptronic. I get around 380-420km around town to ~50l of fuel. So that's 12-13l/100km. On the highway (sitting on 105km/h, passing through the occasional town), I normally get around 9.5l/100km (best is 9.3l, worst is 9.9). I've had the car since January 2006 (had 74,000km on the clock then), and fuel consumption has remained relatively unchanged. I don't leave the car idling with the engine on. I always reset my trip meter (both the one in the instrument panel and the one above the a/c) after each tank of fuel to gauge my consumption, and I've never seen it vary significantly.

I doubt it's my driving style (although I do have the a/c on most of the time). Majority (at least 90%) of gear changes in town occur under 3000rpm. I currently live in Brisbane, but I only drive at night or on weekends - never in peak hour and rarely during the workday. I also used to/concurrently live in Gladstone (city of 30k people, no more than a dozen traffic lights, etc) and fuel consumption was much the same up there. As a comparison on highway driving, I took my parent's 6l V8 VE SS Commodore on a Gladstone-Brisbane trip, and I averaged 10.1l/100km with four people + boot full of luggage. An extra 0.6l/100km isn't bad for something 400kg heavier and with 2 extra cylinders :nuts:

The car is in excellent mechanical condition. It is bog stock - even has the stock air filter. It has 109,00km on the clock. Auto transmission fluid was flushed at 94,000km. Timing belt done at 98,000km. O2 sensor was replaced at around 102,000km. Oil is changed roughly every 6 months. Was last done at the end of June. Engine oil used is Mobil 1 5w-50. Always filled up with premium unleaded (yes I know about the MAF sensor). I go to a trustworthy mechanic, who has not found any other problems with the car. I've added a bottle of injector cleaner to the tank, but with no success. Tyres are good quality Dunlops with heaps of tread. They're on the stock 17" rims and are normally filled up to ~35psi all around. Overall, the car runs great, and I've never had any issues with it.

My dad reckons my fuel consumption is fine, but I'm not so sure. Going through the fuel economy sticky and checking the vote (over half the people who have voted regularly get 500+km out of their tank!) and the comments, I'm left wondering if there's something not quite right about my car. Any thoughts about what to do next would be most appreciated, even if it's saying that it sounds about right - at least I can put my mind to rest :D

yeah around the 9's sounds about right for a TJ, but the holden v8's are rather good on the highway fuel consumption wise, they are only thristy around town or when you decide to hammer them, pretty much like any car really.

You might want to try 38-40 psi in the front tyres. Typical weight distribution for front-drive cars is 70% front / 30% rear. Naturally, this weight distribution will change under acceleration and braking. Overall though, the extra front pressure should lower rolling resistance a little, as well as reducing front tyre slip angles slightly (reduction in understeer). Avoid the temptation to go beyond 40 psi - thats when the outer tread loses contact, accelerating inner tread wear. And remember to switch pressures when you rotate tyres.

Also, has the cooling system's nominal temp been checked out - if it is being regulated too cool, the ECU may be issuing a rich warm-up stoi. Blackened spark plugs would be a tell-tale of how well she's combusting.

Hope this helps.:D

I wouldn't have said that was particularly bad around town with the auto either? 420km on 50L is just under 12L/100, which doesn't seem too bad at all.

The bottled injector cleaner is likely do nothing. The proper way to service them is off car ultrasonically.

A 3rd gen tank is over 70L so you would quite easily be able to crack 500km off a full tank if your getting 400km out of 50L

The bottled injector cleaner is likely do nothing. The proper way to service them is off car ultrasonically.

Everytime i hear of someone talking about cleaning injectors by blasting them with ultrasonic particle waves it makes me thing that they are sending the injectors off to some NASA station or something.

I watch waaaay too much of the Matrix

I used a bottle of injector cleaner in my Verada, improved my economy, not heaps (about 0.5L/100km), but a definite improvement. It's like $10 a bottle, can't hurt to give it a shot.

tbh i don't really think you have a fuel consumption issue, those figures are bang on what I get in my '01 TJ VR-X. I get around 12.5L / 100KM around town and just over 9L / 100KM on the open highway.

You mentioned people getting over 500km to a tank. Well the tank in our cars is 71L. Let's say we do 65 L from full to empty (without letting it run dry) well at 12-13L/100km that means you are getting over 500km in a single tank!!





I know the whole fuel consumption issue is getting discussed to death, but my car's fuel consumption has really been bugging me, and I can't think of what to do next. I also decided against posting it in Lugo's thread, since I didn't want to derail it with all this stuff specific to my car.

I have a 2001 TJ VR-X, 5 speed tiptronic. I get around 380-420km around town to ~50l of fuel. So that's 12-13l/100km. On the highway (sitting on 105km/h, passing through the occasional town), I normally get around 9.5l/100km (best is 9.3l, worst is 9.9). I've had the car since January 2006 (had 74,000km on the clock then), and fuel consumption has remained relatively unchanged. I don't leave the car idling with the engine on. I always reset my trip meter (both the one in the instrument panel and the one above the a/c) after each tank of fuel to gauge my consumption, and I've never seen it vary significantly.

I doubt it's my driving style (although I do have the a/c on most of the time). Majority (at least 90%) of gear changes in town occur under 3000rpm. I currently live in Brisbane, but I only drive at night or on weekends - never in peak hour and rarely during the workday. I also used to/concurrently live in Gladstone (city of 30k people, no more than a dozen traffic lights, etc) and fuel consumption was much the same up there. As a comparison on highway driving, I took my parent's 6l V8 VE SS Commodore on a Gladstone-Brisbane trip, and I averaged 10.1l/100km with four people + boot full of luggage. An extra 0.6l/100km isn't bad for something 400kg heavier and with 2 extra cylinders :nuts:

The car is in excellent mechanical condition. It is bog stock - even has the stock air filter. It has 109,00km on the clock. Auto transmission fluid was flushed at 94,000km. Timing belt done at 98,000km. O2 sensor was replaced at around 102,000km. Oil is changed roughly every 6 months. Was last done at the end of June. Engine oil used is Mobil 1 5w-50. Always filled up with premium unleaded (yes I know about the MAF sensor). I go to a trustworthy mechanic, who has not found any other problems with the car. I've added a bottle of injector cleaner to the tank, but with no success. Tyres are good quality Dunlops with heaps of tread. They're on the stock 17" rims and are normally filled up to ~35psi all around. Overall, the car runs great, and I've never had any issues with it.

My dad reckons my fuel consumption is fine, but I'm not so sure. Going through the fuel economy sticky and checking the vote (over half the people who have voted regularly get 500+km out of their tank!) and the comments, I'm left wondering if there's something not quite right about my car. Any thoughts about what to do next would be most appreciated, even if it's saying that it sounds about right - at least I can put my mind to rest :D

If I use 50l, it's down to about 1/8th on the gauge, so I'm not game enough to drive it much past there :P

I didn't think my around-town figure was too bad, but I felt my highway figure was a tad on the high side. You guys reckon it's about right though, so I'll leave it at that. It's been bugging me for ages, so at least I can now put my mind to rest :)

Thanks for the tyre tip too ogre, I just assumed it was best to have the same figure front and back. I'll pump up the front ones next time I fuel up :)

Put it this way, my mum struggles to get 14L/100km in her VZ with the 3.6 alloytec around town. So if we are getting better than that in cars several years old with a 3.5l engine that was developed 15 years ago Id say we are doing pretty good.

If I use 50l, it's down to about 1/8th on the gauge, so I'm not game enough to drive it much past there :P

I didn't think my around-town figure was too bad, but I felt my highway figure was a tad on the high side. You guys reckon it's about right though, so I'll leave it at that. It's been bugging me for ages, so at least I can now put my mind to rest :)

9.5L/100km was what I got on the highway with my auto Verada.

A few days ago when I took the trip along the Aug 23 cruise route, my needle was on empty most of the trip to the end point (about 30km) then about 40km back. I've found the trip computer to be far more accurate in reporting the remaining fuel than the gauge. When the light can on the trip comp said I'd used 52L, leaving 19L left in the tank. Filled up when the comp said I'd used 59.6L, and it was spot on.

i get between 11 to 12 l per 100k round gladstone in my 05 manual vrx & 9.0l/100k out on the hiway. my 01 tj auto(non tippy) used to get down to 8.2l/100k on the hiway. but your figures sound bout right, red. just off topic, ive got a 03 3.5l pajero which gets 11l/100k out on the hiway which i thinks is awesome for a 2t truck with the aerodynamics of a bick sh*thouse.

Hi,Red i get 12.2 per 1oo in my 05 awd.Thats off peak hour city and fringe country combo.