High fuel consumption with 3.4ltr prado

[high n mighty]

I bought a 3.4 auto prado a couple of months back and it is using 20ltrs per hundred kms, or even a little more.

It looks like I should be expecting around 13ltrs per hundred after a few people commented in the hummer thread so I don't know what to do.

I have purchased a set of extractors which are not yet fitted, I have turfed the toyota std exhaust system for a straight through 2.5" but have not checked the fuel consumption since fitted(been on the beach etc so no point calculating it)

I have replaced the seemingly sticky viscous hub fan with one from my hilux which although appears to disengage earlier still runs until about 2000rpm off the lights. My main concern about the fan is that being an auto whenever it is sitting in overdrive the revs are always below 2000rpm so I think a thermo-fan may make a big difference?????

Where do I go next, sparkplugs? Fuel filter? The airfilter is clean btw.

It has 265 profile AT's on it and probably carries more weight than a prado off the shelf with all the accessories on it but still an extra 7odd ltrs of fuel per hundred kms is a huge difference.

I don't have any plans on going to gas because every gas place wants to put it in the main tank position and I want to keep the 90ltr tank as opposed to the 69ltr sub tank plus it would be nice to be fuel efficient from the start.

Cheers in advance

[high n mighty]

It's only been a few hours but bump

[KaMo]

O2 sensor in the exhaust. There is a VERY detailed thread somewhere on another site about it. I can't find it atm but will search for it later.

[TOTT]

I owned a late 97 for 80,000km. I bought it with 118km on the clock.

It ran 265/75/16 AT's and had a manual gearbox.

The best i woulkd have got on a long run was (15l/100 at 100km/hr, anymore it would start to drink). Around town it was more like 17-17.5 l/100 (this is after factoring in the tire size difference)

[high n mighty]

Thanks Kamo, that would be appreciated.

TOTT, mine is a 97 aswell though that wouldn't matter too much I guess.

Around town it uses 20.9ltrs per hundred almost religiously but I have only taken it on one decent run down the freeway and it didn't seem to use any less although I wasn't checking the consumption on that trip.

I would really like to nip this in the bud and have been doing the above to try and get around it, just starting to get frustrated after so many people here and elsewhere have been telling me that mine is using too much(the bank account is suffering lol)

[high n mighty]

After reading the above posts I started to search for O2 sensor and then efi etc etc via google. I found an interesting site which told me what to bridge in the diagnosis plug to get a self-diagnosis and tell me via the check engine light...

It came up with two codes.

CODE 24) INTAKE AIR TEMPERATURE SENSOR SIGNAL--OPEN OR SHORT IN INTAKE AIR TEMP. SIGNAL
--INTAKE AIR TEMPERATURE CIRCUIT

--INTAKE AIR TEMPERATURE SENSOR

--ECU


CODE 31) MANIFOLD AND/OR AIRFLOW METER SENSOR SIGNAL CIRCUIT
--AIRFLOW METER/CIRCUIT

--MANIFOLD PRESSURE SENSOR/CIRCUIT

--ECU


I think this may be going along the lines of what was previously mentioned by KaMo although it still seems a little broad, can anyone elaborate these codes? I think I know what code 24 means and in my mind it would be constantly dumping enough fuel in for a cold engine thus the massive fuel consumption?

[KaMo]

2 pages for you to read.

Those 2 codes sounds like the MAF sensor in the intake needs cleaning. See here:

http://www.4x4wire.com/toyota/maintenan ... ncep5.html

02 sensor is discussed in the link below. You will not pull a fault code for 02 sensor as it is not 'faulty' rather its reaction time slows as it gets older and it isn't as effective. It is explained in this link:

http://www.4x4wire.com/toyota/4Runner/tech/O2_Sensor/

Our vehicles only have the single 02 sensor pre-cat converter due to different emission regs. The O2 sensors are about $300. I have been meaning to change out the one on my hilux as im getting about 23L/100k's but havent got around to it yet.

Hope this is of some help.

cheers,

kameron.

P.S. could you give us the link to the fault code pulling trick please.

[r0ck_m0nkey]

It was me commenting on it, so just for a comparison to this is roughly how mine is.

I have a 99' GXL 3.4 V6 Auto, also running 265/75R16 BFG MT's as daily tyres. About 150 000km's on it.

On avaerage it gets around 11-1250km's from both tanks. Thats going straight off the speedo without factoring in the tyre size, which technically should be reading slow, but by my checks, is actually spot on. This nets roughly about high 12's to mid 14's per 100km. Cruise Control does get used at every oppurtunity.

Although once it hits soft sand and stuff, it all gets blown out of proportion and drinks it bad.

[high n mighty]

Cheers guys, I don't have any coin for the oxygen sensor atm but should be able to replace it next week. I will clean the AFM tomorrow if I get time.

I'll tell you guys how I go

[DelPrado]

I own a 97' 3.4L auto Prado and have been noticing the ever decreasing fuel econay also!
now i only get about 420km on the 90L tank! (used to get about 550 minimum)

vehicle is up to 215,000kms and is going in for another service on Saturday. I am getting the guys at Toyota to look at the possible cause of this lack in economy (other than the 33" BFG muddies, and rear drawers + fridge e.t.c) lol

I have had the car for over 2 years now and done approx 30,000kms.
used to get about 1050 - 1100kms off both tanks when i first bought it.

have seen various threads on the air sensor being dirty, but when i investigatd it i found mine was a complete sealed unit and the actual sensor could not be reached.
i will check this out wiht the Toyo guys and see what a replacement one will cost, then let you know.

cheers!

[high n mighty]

I cleaned the AFM yesterday(both the afm itself and the terminals with the suggested electrical contact cleaner). The two wires in the afm didn't appear to be covered in anything but the plug had some dirt in it.

I will need to fill the tanks up and take note of the klms but it did drive different today, seemed to accelerate quicker without as much effort which has to mean something I hope


Just on a side note, I must have been wrong with my rate of fuel consumption figures. I have never reached 650klms out of both tanks

[KaMo]

Did you order an 02 sensor HnM? I rang local toyota yesterday and the part is ex. Japan and about 4 weeks lol. Oh and $303 + gst

[ferrit]

you only get 650kms out of BOTH tanks???

And we grumble if we dont get 1400kms out of both thanks!

Boy im glad we own a diesel! even if it has just shat its 2nd front diff in 20,000kms!

[dogoff]

The two codes you had in your car sounds like someone had the air flow meter disconnected with the ignition on, if the engine light is not constantly its not a concern now.

Clear you codes and then recheck
air flow meters if they have two screws , you can clean them , but replacing them is the best opion

[high n mighty]

I cleaned the airflow meter with contact cleaner and it seemed to make a difference, I also serviced the clutch fan so now it is no longer locked on solid. The 02 sensor comes next though it won't be done until I have these extractors fitted(no point double handling it) and cash is tight (unless someone wants to fit the extractors ).

I personally think the dodgey fan had a damn lot to do with my fuel consumption although it wouldn't be the only cause, however things can only get better

Ferrit, burn that pos your parents own. Mine might be expensive on fuel but your family have spent more money on parts than I have on fuel. In this instance I feel it is cheaper to own a petrol Prado

Dogoff, how do I reset the codes???

Cheers for the continuing help everyone and feel free to lend me even more advice

[KaMo]

No more advice...but what extractors have you got for it?

[revin]

you only get 650kms out of BOTH tanks???

And we grumble if we dont get 1400kms out of both thanks!

Boy im glad we own a diesel! even if it has just shat its 2nd front diff in 20,000kms!

Even I get 800 out of both my tanks in my cruiser

Guess I cant complain too much now can I

[high n mighty]

No more advice...but what extractors have you got for it?

Wildcats, they come from the Genie factory and cost me $460.


Just bumping this TTT also and hopefully someone can help me out(not that you guys havent).


The fan is still working great and I haven't really checked consumption although I used 3/4 of the main tank in less than 200kms this weekend I did about 40kms on the very soft beach in low range though.....


I had Adam clear the codes from the diagnosis and will re-check it through the week but his computer said that everything is running fine

I can't believe this thing, it does not blow smoke and runs perfectly apart from the consumtion while everyone else is using 10ltrs per hundred less than me

It doesn't leak the fuel either

[dogoff]

To clear the codes pull the efi fuse out for 5 sec with the ign off. Make sure you have pulled your jumper wire out whilst you do this

[high n mighty]

Thanks mate, I had Adam do it with a diagnosis computer while he was re-checking the codes.

[KaMo]

Have just installed a new 02 sensor and grabbed a full tank of juice. Stay tuned for results.

Better bloody make some difference or i'll

[high n mighty]

Did you end up finding the engine codes? I don't remember if I found them in your links or searched them myself

[KaMo]

Did you end up finding the engine codes? I don't remember if I found them in your links or searched them myself

You searched them lol. And nup i didn't bother trying to pull any codes. I just replaced the sensor. Coventrys do a Bosch 4 wire universal sensor for $125+. I had to get a credit for some other bits and pieces so walked out with the sensor. Just need to cut the plug off of the old sensor and join it onto the new sensor with the joiners provided and at the same length as the old sensor (so as to maintain set resistance I would be guessing.)

Hope it makes a bit of difference.

[high n mighty]

This one will spin ya out I am sure. My Prado does not have a cat or an 02 sensor. Apparently toyota "commercial vehicles"(rv spec) did not have catalytic convertors and the 02 sensor is a spin out although the manifolds did not have provisions for an 02 sensor nor did the brand new extractors.

I am still having fuel issues after the exhaust, extractors and cleaning everything to remove codes.


I think something is a miss after you guys talking about an 02 sensor and I don't have one.

Must be something big on

[KaMo]

Valve clearances?

[high n mighty]

I'm not sure on valve clearance and in my limited knowledge wonder how it would use more fuel except for the need to put the foot down more for power which maybe I have.


I have just found a friend has an auto GXL prado a year newer, maybe I should drive that although with std tyres against my 265's I am sure acceleration would be different from the start?

[KaMo]

Yer not sure...just throwing ideas around

[r0ck_m0nkey]

I have just found a friend has an auto GXL prado a year newer, maybe I should drive that although with std tyres against my 265's I am sure acceleration would be different from the start?

I don't think there was much of a difference in mine from going from standard sized HT's to the slightly larger MT's. A GXL has 265/70R16's standard as apposed to the slightly larger 265/75R16's.

[high n mighty]

Sounds like a plan then. I will be up there next saturday and take it for a spin if it hasn't been sold by then.


It has also been suggested that the exhaust I had fitted is now too free flowing and I need a 8" glass packed something or other muffler which will quieten it down, give it more low down power(currently doesn't pull until 3000rpm odd) and increase the economy.


I like every one of those ideas IF it works, I don't want to replace a 5 week old exhaust that was previously recommended by another shop

[high n mighty]

Stupid prado