Improving fuel consumption - 95 Series V6 petrol 3.4

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

Gosling that sounds ok. I use to get pretty much 17,2L per 100 most of the time. Best was 12.8 freeway. Mine was a 3.4L V6 97 grande....Cheers Steve

[Gosling1 Junior Member Find all posts View Profile Close Gosling1]

.....my prado 1997 rv has main tank and sub tank I usually get 70l in main and 50 l in sub I have always emptied both tanks to near empty......3.4l motor still doesn't use oil and feels as strong as new......

The 3.4 is a great motor, no doubt. I am still a bit confused with your RV model though - according to the NRMA in 1996 - all models except the RV - came with a main and sub tank. Main is 90 litres, sub is 69. ....they must have changed the 97 RV to a duel-tank setup ?

....Prado features a dual fuel tank system on all but the base RV, which enables it to carry 159 litres of fuel via a ninety litre main tank and a sixty nine litre sub tank. Both tanks are filled through a common filler neck with a separate orifice for each tank....

If you were getting an average of 900km from around 120l of fuel (that is - using both tanks) - that is about 13.3 l / 100km. Great economy, I would love to get mine down that low. In the same article though - NRMA record a better fuel economy figure than they did a year later.......

....Fuel consumption with the V6 auto was not very impressive at 14.7 litres/100 km overall, although better than comparative models....

I would be way happy to see < 15l / 100km out of my rig.....around town anyway.

....Gosling that sounds ok. I use to get pretty much 17,2L per 100 most of the time. Best was 12.8 freeway. Mine was a 3.4L V6 97 grande....Cheers Steve......

cheers - that does seem to be a common figure for city driving......

One thing I have noticed with using the sub-tank down to the 'E' on the guage - on the highway I once squeezed about 70 more km out of the sub-tank before it actually ran dry.....did this just to see how far it would go. Have not tried this on the main tank yet.....

[hawks667 Member Find all posts View Profile Close hawks667]

Its been said on numerous occasions, but keeping the MAF sensor clean does work.

A couple of months ago, i did some rewiring on the dual battery set up & had the crank disconnected for a few hours. Once it was all finished, both batteries were reconnected..Nothing unusual, but after this, i swear to god the old girl was running better & even saw better economy. I'm wondering if it resets the ECU?

A mix of 70/30 mix of highway and city saw me with dead on 1000 klms out of it, fueling it up i put 134l in it. So pretty happy with it, given its got a 2' lift with 265/75/16, steel bar, winch, snorkel, drawers & a fair bit of other fruit on it. Its an auto with 273k on the clock.

I normally drive for economy and on average, get 850 out of 130l around town & the 1000 mark when on the highway. Mind you, i have never managed to put more than 140l in it, a fair way from the 159l its supposed to hold.

[Playdoh96 Member Find all posts View Profile Close Playdoh96]

In the rv range you had 2 engine options. The 4 cyl only got the single tank. And the v6 got both.

[Gosling1 Junior Member Find all posts View Profile Close Gosling1]

......Its been said on numerous occasions, but keeping the MAF sensor clean does work......I normally drive for economy and on average, get 850 out of 130l around town .....

I have to thank this forum for pointing out the MAF sensor issue - it was a few years ago now, but the rig was running a bit rough, using a lot more fuel than normal - but the worst symptom was the way the auto was working......gear changes were rough, kickdown not working properly etc. When I googled 'Prado running rough' .....this forum and 1 thread in particular came up. Cleaned the MAF sensor and bingo - running well again straight away - its been kept clean as a whistle ever since.

850km from 130l around town is good - 15.2l / 100km. This is where I want to get my rig. Only a few months ago - when both tanks were pretty dry - I managed to squeeze 150 litres in. The servo attendant was amazed reckoned he had never seen anyone put so much fuel into 1 car .......

........In the rv range you had 2 engine options. The 4 cyl only got the single tank. And the v6 got both......

thanks - the 1996 article didn't specify which type of RV (4 or 6) - but that makes sense.

[K & M McF Senior Member Find all posts View Profile Close K & M McF]

I have had my 90 series since new in June 1999. It has done less than 200k, but a hard 200k of towing a 2+ tonne boat or real 4WDriving. When used on the highway fully loaded I average 13 to 13.5 litres per 100 km. This includes a rooftop tent. When I used to drive it to work, its average around town was about 14-15 l/100km. Without weight and rooftop items, on the highway it was about 11 to 12.5 l/100km. The economy is still roughly the same as it was 15 years ago when new.

I accelerate slow, I sit on 100 on 110 freeways, sometimes sit on 90 on 100 roads (when it does not inconvenience others) and generally take it easy. I consider the economy to be extremely good considering the size of the car and the weight it carries.

[glen_ep Addicted PP Member Find all posts View Profile Close glen_ep]

Here's my latest fuel figures from the weekend. Air filter and MAF were clean. Figures are L per 100km.

14.3L ULP 91 - 370km of highway @ 97km/h + cruise control + heavy winds
19.0L mixed - 600km mountain roads/offroad/heavy snow
12.8L PULP 98 - 370km of highway @ 95km/h + partial cruise control

I take it slow on the highway due to my gear ratios (RPM's sit around 2,200 for above speeds), but on mountain roads and dirt my driving style changes dramatically - fast and aggressive.

Half way back along the 370km drive I decided to turn off the cruise control as I suspect it consumes more fuel. It definitely maintains higher RPM's for down hills and over crests, and it also drops the gear more frequently on ascents. Without cruise I can climb ascents without gear changes (sometimes loose a few km/h), and on down hills can let off the acceleration entirely. Definitely something worth experimenting with.

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

Glen, 3 prados all with cruise all shit to use unless on flat ground. Worst factory cruise control I've come across. When climbing a slight incline it will wait till the speed has dropped off, then think "oh shit I better get back to 110 NOW" back one gear oops not enough let's go back to 3 and rev to nearly 5 thou then ooh were doing 115/120 now better back off, back down under 110 and we start the process again untill it settles it's self down. Unless it's flat ground I don't even bother turning it on. A lot more economical to use the right foot to the conditions and feed the power on gently or knock the auto back one gog manually.... All cruise controls have all acted the same on all my 3 prado's... Cheers Steve

[Gosling1 Junior Member Find all posts View Profile Close Gosling1]

Have to agree about the cruise control, contributing to higher fuel use on the highway. When I drive up the Hume to Sydney with a couple of race-bikes in the trailer and a bit of gear on board - normally I just flick the cruise on for the downhill and flat sections, and turn it off well before the uphill stretches. There is quite a bit of variation between Canberra to Mittagong, but once you hit the edge of the Sydney basin.....well its all downhill from there

The cruise does tend to hang onto a lower gear (and thus higher revs) for far longer that it should, after any slight uphill incline. At least its easy to flick on/off as needed......

Had bugger-all change to the fuel economy after fitting the new air filter.......35l for 200km, 17.5l/100km around town. Although after the new filter was fitted, I did notice that the response from the throttle felt crisper - and the gear-changes also felt ...better ? A bit smoother/quicker. Not sure why they would be - but they did.

In a couple of weeks the rig is going in for that high-pressure injector cleaner, MAF ultrasonic clean and a new fuel filter. One of the boys at work who was a mechanic for about a decade - also mentioned that the coolant-temperature sensor should be checked out. They can go out of range without sending a fault signal to the ECU......according to him - and if the coolant sensor is a bit out, it may lead to a richer mixture than otherwise. Worth checking out anyway.

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

Have to agree about the cruise control, contributing to higher fuel use on the highway. When I drive up the Hume to Sydney with a couple of race-bikes in the trailer and a bit of gear on board - normally I just flick the cruise on for the downhill and flat sections, and turn it off well before the uphill stretches. There is quite a bit of variation between Canberra to Mittagong, but once you hit the edge of the Sydney basin.....well its all downhill from there

The cruise does tend to hang onto a lower gear (and thus higher revs) for far longer that it should, after any slight uphill incline. At least its easy to flick on/off as needed......

Had bugger-all change to the fuel economy after fitting the new air filter.......35l for 200km, 17.5l/100km around town. Although after the new filter was fitted, I did notice that the response from the throttle felt crisper - and the gear-changes also felt ...better ? A bit smoother/quicker. Not sure why they would be - but they did.

In a couple of weeks the rig is going in for that high-pressure injector cleaner, MAF ultrasonic clean and a new fuel filter. One of the boys at work who was a mechanic for about a decade - also mentioned that the coolant-temperature sensor should be checked out. They can go out of range without sending a fault signal to the ECU......according to him - and if the coolant sensor is a bit out, it may lead to a richer mixture than otherwise. Worth checking out anyway.

When you use cruise control with any vehicle, you will have to help it out when it comes to hills, I always apply a little bit of weight to the accelerator before the hill, this stops the vehicle slowing down on the hill then kicking down a gear or two and then going over the speed set. Thus saving fuel in the long run.
As for the coolant temp sensor, I think it would have to be way out to cause a problem like using more fuel. if you have an auto trans, you may notice that it wont go into 4th gear until the water temp has reached to around about the 1/8th mark. Plus the ECU on the 90 doesn't have the capacity to detect a fault for the coolant temp, there is only a low coolant notification light.

[Gosling1 Junior Member Find all posts View Profile Close Gosling1]

That is pretty much exactly how I do hills with the cruise - there are some big-un's on the way to Sincity

My rig is an auto - it's been really cold here lately, frosty mornings with lots of ice on the windscreen ... - and I leave the o/d switch on all the time. The auto drops into 4th at the first change after turning onto our main street? This is well before the temp needle has started to move. Its a 95 series (11/99 build, first regoe'd in 2000) - not a 90 series. Would this model change make a difference to the way the auto works, or the coolant temp. sensor ?

I booked it in today for the high-pressure injector flush, MAF and TB clean as well as a diagnostic check, in a couple of weeks time ( busy workshop ) - and mentioned the temp-sensor issue to the workshop manager. He said that it was something they would look at during the job, as part of the overall diganostic check.

One thing I have tried to find on the forum but failed - is info about the spark plugs. Specifically - why does Toyota recommend only dual-ground plugs ?? Is this really an issue ? I would like to put some new Iridium plugs at the next plug change (Xmas) - and these just come in the standard single-ground style.

Any info about this would be great

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

That is pretty much exactly how I do hills with the cruise - there are some big-un's on the way to Sincity

My rig is an auto - it's been really cold here lately, frosty mornings with lots of ice on the windscreen ... - and I leave the o/d switch on all the time. The auto drops into 4th at the first change after turning onto our main street? This is well before the temp needle has started to move. Its a 95 series (11/99 build, first regoe'd in 2000) - not a 90 series. Would this model change make a difference to the way the auto works, or the coolant temp. sensor ?

I booked it in today for the high-pressure injector flush, MAF and TB clean as well as a diagnostic check, in a couple of weeks time ( busy workshop ) - and mentioned the temp-sensor issue to the workshop manager. He said that it was something they would look at during the job, as part of the overall diganostic check.

One thing I have tried to find on the forum but failed - is info about the spark plugs. Specifically - why does Toyota recommend only dual-ground plugs ?? Is this really an issue ? I would like to put some new Iridium plugs at the next plug change (Xmas) - and these just come in the standard single-ground style.

Any info about this would be great

Australia only got the 95 series, which is the 5 door model, 90 series is the 3 door model, but everyone just calls both of them 90 series.
The auto works the same in both series as well as in the 80 series landcruiser, where the auto originates from.
If the auto is dropping into 4th when still cold then you have a MAF problem.
As for the spark plugs, yes you need to use the twin ground plugs as a minimum, and the iridium ones are normally quad ground, if your looking at single ground, they would be the wrong ones. One thing I have found is that when using iridium plugs, there is no difference in performance or fuel consumption, you just pay more for them and they will only last for around 60000ks. They cost 8 times as much and you change them 4 times less. you do the math!!! they are not worth it.

[Patty94 Lurker Find all posts View Profile Close Patty94]

Im getting roughly 250km out of the sub
changed the air filter now ill put in some injector cleaner and fill her up with 98 and see how she goes then ill buy a new MAF sensor hopefully it starts using less ill be happy with 18L/100

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

Im getting roughly 250km out of the sub
changed the air filter now ill put in some injector cleaner and fill her up with 98 and see how she goes then ill buy a new MAF sensor hopefully it starts using less ill be happy with 18L/100

Don't buy a new MAF sensor, as you will be looking at around $1000 genuine and $600 aftermarket, just buy some MAF cleaner and give it a good dose of it according to the directions on the can, allow to completely dry before putting it back in. Also clean the TPS, it is a bigger job to do as you need to take off the induction system, but it will make things run much better too. forget about using 98 octane as that is just pouring money down the drain as the motor was designed to run on 91 and 91 only, there is no benefit using the higher octane fuel. If you can find E10 95 octane cheaper than reg 91 then use it. Injector cleaners are very caustic and can damage the injector nozzles, so only use with a full tank and then only on a long journey to use all the fuel up.

[Gosling1 Junior Member Find all posts View Profile Close Gosling1]

.....Australia only got the 95 series, which is the 5 door model, 90 series is the 3 door model, but everyone just calls both of them 90 series......

thanks for that - I always thought that the 90 Series was the 3 or 5 door models from July 96 through to July 99, and the 95 model was the updated one introduced in August 99 ? The dealer has always referred to my rig as a 95 .....I guess it doesn't matter that much as they all run the same engine. Is there anywhere on the forum that has a definitive list of the upgrades between the 90 and 95 series models ?

....The auto works the same in both series as well as in the 80 series landcruiser, where the auto originates from....If the auto is dropping into 4th when still cold then you have a MAF problem....

Hoping that the MAF and TB clean in a couple of weeks should sort this out, if any problem exists - the auto seems to be working fine - it just selects through the gears like it always has, whether the engine temp is hot or cold ? Its not laboring or anything like that......I know when the MAF was really dirty the first time around, there were definite issues with the auto, it was changing gears all over the place, sometimes holding a gear too long, or not dropping back down a gear or 2 when going uphill ? Once the MAF was cleaned - it went back to normal. Its been like that ever since...(MAF has been kept spotless since that first clean). In the workshop manual - it refers to ECU controlling the auto solenoids with input signals from throttle, engine RPM, vehicle speed, trans oil temp, selector position and a/c compressor - but nothing about engine temp ?

.....As for the spark plugs, yes you need to use the twin ground plugs as a minimum, and the iridium ones are normally quad ground, if your looking at single ground, they would be the wrong ones. One thing I have found is that when using iridium plugs, there is no difference in performance or fuel consumption, you just pay more for them and they will only last for around 60000ks. They cost 8 times as much and you change them 4 times less. you do the math!!! they are not worth it......

cool, thanks. I have found some quad-ground plugs from Bosch - Platinum IR Fusion 4501, $9.50US per plug, free postage from the US.... Not too bad. Will also check this with the workshop in a couple of weeks and see what they reckon about these plugs. Could be a woftam - what I don't understand is why there are so many other plugs available for the 3.4 V6 motor - that are all single-ground plugs ? Seems weird....

Appreciate the feedback heaps, the cook has been driving this rig for the past 10 years and all I have done is oil/filter changes and tyre rotations - now that its now all mine, its good to be getting into it a bit more ......