How to improve fuel economy of v6 prado

[karlmagoo Junior Member Find all posts View Profile Close karlmagoo]

Mate im getting roughly 14L/100, ends up around 1200klms average to a tank, so 600 per 90L, AU falcon ute i had previously was around 500/550 to an 80L tank, pretty happy for the size of vehicle, and considering there is plenty of power there im not complaining, as others stated, run 40psi in the tyres and drive like grandma. As for the blunt post, ignore it, there isn't a forum in the world where the long time local yokels don't feel the need to share a bit of negativity, you,d think it would be easier to simply not read ya post, or ignore it.




cheers


cheers

[Auss15 Junior Member Find all posts View Profile Close Auss15]

Hey Auss15 ease up mate it was just a question. I bought my prado full knowing fuel economy would not always be great.

Not having a shot at you, just saying that buying a Prado is about all the great features it has to offer for numerous user demands and like any vehicle there are always weaknesses and fuel usage is one, and I accept that.

A Getz might be cheap to run but it wont offer the functionality of a Prado

[datsezy Lurker Find all posts View Profile Close datsezy]

If it's done more than 100,000km it's a good idea to replace the exhaust oxygen sensors.

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Hi there datsezy, mate I wouldn't bother unless the fuel economy goes out the window or there are idling issues. Its not that common for them to shit themselves unless the vehicle has been running very high temps due to head issues (also not common) or the heads have gone at some stage allowing condensation from the head/s down the exhaust system. There a pretty robust motor if all is kept in order eg oil changes/coolant changes etc, the normal maintenance of a vehicle......Cheers Steve

[datsezy Lurker Find all posts View Profile Close datsezy]

G'day Steve, just trying to help. They are actually a serviceable part, with a service life of around 100,000km, after which time their reaction time slows (visible on an oscilloscope), thus having a negative impact on fuel economy & emissions. I'm an Auto Electrician by trade and see the difference fresh ones can make every week.
Another improvement to economy & driveability can be made by getting a good quality fuel system/combustion chamber clean done, service her regularly & use the correct grade, good quality oil.
LPG is also an option for some. I converted mine, and get approx 330km from a 70 litre tank, and still have one 90 litre fuel tank. It suits me and the way I use my Prado.
The biggest factor with fuel consumption is usually the way you drive her.

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

""just trying to help"" yeah mate not having a go at you in any way at all. Been an auto sparky you probably would come across this more then what I have read. Your comment ""The biggest factor with fuel consumption is usually the way you drive her. "" would agree with you there 100%. Definitely makes a huge difference......Im not a fan of LPG personally myself so I wont ever go down that path again.......Cheers Steve

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

Obviously not paying >$1.20 per litre for LPG.

[geograzza Member Find all posts View Profile Close geograzza]

I'm getting about 18/100 on the highway, mid 20s around town. I know they are thirsty compared to a small car, but mine is ridiculous, only get about 900k out of both tanks. I've cleaned the MAF sensor, put a new air-filter, keep it regularly serviced, run the tyres at 40psi, and generally try to keep my right foot fairly light. It's got about 170,000 on the clock. I've mentioned it's thirst when I've had it serviced (Holden dealer where I bought it 2nd hand), and they can't find anything wrong, but then I don't know that they have the right gear to test it properly. I think they've just tested for fuel system leaks, and for binding brakes. I'm not expecting 4 cylinder economy, but I've seen road tests where they got about 11/100 highway and 15/100 city. I'd be happy if I managed 15 on the highway, I'd be over the moon to get 11.

The above mention of the O2 sensors has me interested. What would be a ballpark figure to have them replaced?

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Wholly shit geograzza, that's worse then a 100 series petrol. I'd be going down the path of new oxygen sensors for it by the sounds of it....... Cheers Steve

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

I'm getting about 18/100 on the highway, mid 20s around town. I know they are thirsty compared to a small car, but mine is ridiculous, only get about 900k out of both tanks. I've cleaned the MAF sensor, put a new air-filter, keep it regularly serviced, run the tyres at 40psi, and generally try to keep my right foot fairly light. It's got about 170,000 on the clock. I've mentioned it's thirst when I've had it serviced (Holden dealer where I bought it 2nd hand), and they can't find anything wrong, but then I don't know that they have the right gear to test it properly. I think they've just tested for fuel system leaks, and for binding brakes. I'm not expecting 4 cylinder economy, but I've seen road tests where they got about 11/100 highway and 15/100 city. I'd be happy if I managed 15 on the highway, I'd be over the moon to get 11.

The above mention of the O2 sensors has me interested. What would be a ballpark figure to have them replaced?

I have seen my customers getting 1200k on unleaded with a bit left in the tank, but at that mileage, I don't think i will go down the petrol road.....

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Hi there ####, what motor is in yours, 1kz or D4D ??........cheers Steve

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

I average 11.5L per 100 freeway driving so would give me a range of approx 1500 which would be pretty close to an MT tanks. I doubt those with a 1 KZ would do that much better, D4D yes for sure. I have had the 1KZ in the grande in auto and my 120 petrol cruising at 110kph gives me better economy. Then take into account the service costs for the diesel, original purchase price over a diesel (not so much now with the 150's not much difference now), generally I can get my unleaded 15/20c per litre cheaper then diesel when at the low point for the cycle, (in Sydney anyway) petrol filters for some reason are heaps cheaper, plus take into account if you really look after your diesel then oil and filter every 5k, then injectors or pump outside of warranty, take all this into account diesels aren't like they use to be. If I was towing/touring year round then yes I would buy diesel but for myself personally and the 4 weeks a year I may tow ill cop the extra fuel bill. Only reason I didn't buy D4D last time I didn't have the extra $$ without borrowing but to be honest I don't regret for a minute buying what we have, great vehicle except I do miss traction control an the duel aircon....... Just my opinion Cheers Steve

[datsezy Lurker Find all posts View Profile Close datsezy]

Unless you drive while wearing lead boots geograzza, I would say there is definitely an issue with your bus. At that rate she would have black smoke (un-burnt fuel) coming out the exhaust? There are 4 exhaust oxygen sensors on the 3RZ-FE and the part number is different >08/04 and 08/04>. 2 pre-catalytic converter & 2 post-cat. The 2 post cat ones really only monitor that the cat is doing it's job, so don't worry about those at the moment. Try to get genuine sensors, as I've had issues with aftermarket ones. You can source genuine ones from places other than the dealer, at a much better price. You should be able to buy them for under $250ea, about $200ea is a really good price, plus labour for fitting (around an hour).
You can actually un-plug the oxygen sensors and drive around with them unplugged (the check engine warning lamp will be on & it will log a fault code, which will need to be erased with a scan tool) to see if there is any improvement before you buy them, as the Engine Control Unit/Module will run in 'open loop' as it has a bias programmed into it for emission control, or for when the sensors are cold.
There are other factors which can cause excessive fuel consumption, and these should be checked before replacing the oxygen sensors:
- Excessive fuel pressure
- Faulty Air Flow Meter ('cleaning' them doesn't always fix them)
- Faulty Coolant Temp Sensor
- Wiring fault (bad earth)
- ECU fault
If you know someone with the same model vehicle, see if you can swap Air Flow Meters for a week to see if there's any difference, as they are easy to swap.
I hope some of this helps.

[geograzza Member Find all posts View Profile Close geograzza]

Thanks datsezy. My engine is actually the 1GR-FE, does it have the same # of sensors? I've noticed that for example if the missus takes it up the street, I can smell a distinct fuel smell, so I'm pretty sure it is running very rich. At idle it doesn't seem to have an abnormal smell though.

I've been getting it serviced at the Holden dealership where I bought it because it is a condition of their extended warranty, and they do actually have reasonably priced services. Now that that's almost run out, I think next service I might take it to the Toyota dealer for them to have a look at. In theory they'll have all the correct test gear to see if something is amiss. I also need to get the sovereign bar mounts done too, so I'll aim to kill 2 birds with the one stone.

[datsezy Lurker Find all posts View Profile Close datsezy]

Yeah sorry mate I mistakenly typed 3RZ-FE instead of 1GR-was helping another bloke with a 3RZ when I wrote it. In my experience dealerships don't really specialize in diagnostics, they are service stations. Their approach to diagnosis is if it doesn't have a Diagnostic Trouble Code there is nothing to diagnose, or to replace parts in a logical order starting with the most likely or common fault. Once the part is on your car, usually you own it, wether it fixes the fault or not, and you could end up with a huge bill at the end of the exercise, and the fault may still not be rectified. I don't agree with this method.
Try to find a workshop that specializes in engine management diagnostics. Workshops that specialize in aftermarket ECUs/Dyno tuning/re-mapping of factory ECUs are very good at looking at fuel trims & oxygen sensor outputs to diagnose the actual fault with the vehicle.