Hilux to 1uz conversion fuel economy?

[mick08]

What fuel economy are people gettin with their 1uz's? I've got 1 in an extra cab 2wd hilux and am getting 16L/100klm or approx 350klm out of a 55L tank, which i thought was a bit heavy i was expecting about 14L/100klm,any ideas on how to get better fuel consumption out of the 1uz?My injectors are a bit ticky but eng always runs smooth and never misses a beat its only got 105,000 on the clock.

[Dieseltrain]

Could try aftermarket ecu or piggyback to tune some fuel out of it ?

[mick08]

mmm,piggy back, have you done one before is it worth the $1000 plus to get better fuel economy, if my injectors arn't spraying the best as i think they are original, could this chew more juice?

[CrUZida]

1UZ's should get 12-14L around town (depending on how heavy your foot is) and 9-11L on the highway (per 100km's).
This is with aircon off.
Any 1UZ that is not in this region (and is being driven nicely) has issues somewhere (or is in a very heavy car)

To get better fuel economy there is a lot that can be done.
New cats ($400ish)
Clean injectors ($300ish)
New plugs ($120ish)
New leads ($250ish)
New dizzy caps ($90ish)
New rotors ($50ish)
New o2 sensors ($120ish)
Clean AFM ($15)
Clean ISCV
Clean TB

You just have to weigh up whether you are willing to spend the money only to get either a minimal result, or potentially no result at all.


There is always the possibility that your conversion was poorly wired, which can also cause high fuel consumption.

[Cuzzo]

Thanks for the info guys,

Im getting 360kms from a cressida tank. 65L im pretty sure. My foot is heavy, but doesnt mean all of the time.

Highway driving around 450kms no heavy foot.

Thanks for the list cruzida ive been wondering what i could change to help the economy. Thats the only thing making me want to sell it.

[mick08]

I think i may have issues then caus my ute has new hi-flow metal cats,new iridium plugs,new universal 1 wire 02 sensors,the iscv has been cleaned and lubed but seems to work intermittantly, by that i mean it used to start cold with rpms up to 1100 but all of a sudden stopped and now starts cold at 650rpm which hasn't bothered me as it doesn't stall or effect drivability, the TB would show signs of dirt would it if it needed cleaning?It is very clean inside and the AFM is very clean also. The dizzy leads, caps, and rotors are untouched as the engine runs so smoothly i would have thought some sort of miss or rough idle complaint would show up if they were the cause, I also have a new air cleaner installed which is a genuine toyota part as i retained the soarer airbox in the hilux engine bay, the ute runs 4.11 diff gears and does 2500rpm at 100kph in overdrive,i switch the overdrive off in 60-70kph zones on the way to work as the auto is constantly changing down 2gears when i start/stop in traffic,but when i eventually get out of traffic and onto hiway its always in overdrive, I do love the 1uz engine but when mates at work are gettin better economy in LS1 powered luxobarge commonwhores i start to rethink, maybe LS1 in a 4wd is the way to go next time.

[Dieseltrain]

Are you sure those 02 sensors work well with the toyota Ecu ? Cleaning injectors can help , but thats only if the injectors themselves need cleaning, normally associated with rough idle and not so smooth running .

SOmetimes leaking Caps in the actual ECU can cause poor economy as well . Very common with these Ecu's/

[CrUZida]

Yes, leaking caps can do it too, I forgot about that one.
The aftermarket o2 sensors should work fine, assuming they are actually o2 sensors and not just chunks of metal.

My Celsior can get as low as 9.5L/100km's on the highway, and that includes some use of aircon and spirited overtaking.
On top of that the only thing on that list that has been done is the cats. I've got a free flowing exhaust (stock headers) but the cat is a cheap ass ebay one as far as I can tell.

Nothing else on that list above has been touched from factory to the best of my knowledge, at least not by me in the 50,000+km's I've had the car.

[mick08]

please explain leaking caps? that must mean dissassembly of the ecu i suspect, is that a good thing, isn't it sealed?

[MWP]

Its not sealed, top comes off very easily with a few screws.
Obvious signs of problems is disocoloration around the base of electrolytic caps and bulging of the aluminium tops.

[mick08]

And if its fucked can it be fixed or should i get another soarer ecu?

[CrUZida]

Someone confident and handy with a soldering iron can fix it for about $4 worth of caps.

[Sciflyer]

This is what you'll be looking at

I get pretty much the same fuel econ as crUZida in my Soarer, and thats with a shorter ratio diff (4.08) so im gonna go out on a limb here and say that you Hilux should be doing the same or better given it wont weigh what our cars do

I wouls start with the easy stuff first - couple of bottles of injector cleaner and clean the afm (use a proper spray electrical cleaner, dont touch it and dont be too concerned if the car runs like shit until it fully dries out)

If youre going to pull the plugs it might be a good idea to do a compression test too

These engines are so smooth its not always obvious when something isnt 100%

[mick08]

Thanx very much for the pic's, you guys on toymods are very helpful indeed,i don't know what i would have done without toymods with this conversion,every time i've asked a question i get positive and helpful feedback from numerous people, I think the injectors are past a clean as i've already run slick50 thru them and it made no difference,me thinks i'll do the injectors first and go from there they are probly original never been touched, thanx again guys.

[litldv8]

hi mick when i did my conversion my 1uz injectors were stuck shut. but the motor had been sitting for a while. i payed $16.50/ injector to clean them.
neil