I know. Its another fuel consumption thread.

[Superforg]

1996 NJ paj. Auto, 3.5. Dual fuel.

I can't find the thread that listed all the things to check for fuel related issues. Driving distance on gas it uses about 16 liters/100k. On BP ultimate it uses about 14.5 liters 100k. but driving around town it uses 30 liters/100k on gas and 23 liters/100k on BP ultimate. What do I need to test to figure out these problem. No codes are thrown at all. tyres are standard size and are ATRs.

Help?

[Wooly Mammoth]

Check:
Air filter
Clean MAF
O2 sensor
Injectors clean?
spark plug/leads ok?

These are the ones I can think of a 01:20am
I'm sure I've missed something :P

im getting 16/17L per 100Km in hilly hobart

[pajeroman3lt]

My 3lt NJ sucks anywhere between 14 to 20lt. Doesn't matter how I drive either, the more gentle I drive the more fuel it uses.

[nj swb]

What sort of mixer are you using? Some of the real simple mixers simply strangle the engine, and kill fuel consumption - in the early '90s I worked with a bloke who put a simple mixer system on a 3 litre petrol hilux, and could only get 10mpg on gas. Petrol wasn't much better.

[TristanNL]

What sort of mixer are you using? Some of the real simple mixers simply strangle the engine, and kill fuel consumption - in the early '90s I worked with a bloke who put a simple mixer system on a 3 litre petrol hilux, and could only get 10mpg on gas. Petrol wasn't much better.

What's a 10mpg? Haha - vote one metric!

[Goodsy]

23.5L/100Km's American gallon
28.3L/100km's Imperial gallon

[Downunder35m]

No matter if diesel or petrol, if the system is clean the fuel consumption should be ok - if not tuning is needed.
Over the years I had all sorts of cars that needed "a look", friends, family, you name it.
A Magna was the worst, using close to 25L/100km and struggling to get up a small hill.
After several failed tune ups I was asked to look before it goes to scrap.
Air filter was simply black, airbox full of leaves, fuel filter blocked with slimy goo, air leaks on the intake...
A quick run to the auto shop and a few hours later the car was running fine again, after a bit of tuning consumption down to 9.5L.

With more electronics and emmision control systems things are not always easier compared to simple cars.
If possible first order of business is checking for fault codes, followed by cleaning the usual syspects.
Since emmission control and the return of exhaust gases was introduced motors started to suffer.
What should be cleaned during a service is often overlooked by the mechanic to save some time as the car still runs fine.

[damo03]

Unless the knock sensor on a pajero exists and is sophistocated to adjust timing to account for extra octane in premium, that is wasted money as well. As the potential extra power in the octane is not utilised. Im not sure if the petrol engines have this technology on the 3.5lt?

My nl petrol uses about 16l/100 around town driving smoothly and without agressive acceleration. 13l/100km on highway unloaded no wind.

[ARGS]

you're meant to put premium in the 6g74 though at least the 95ron

[Pauly Faulkner]

You can run normal unleaded in the 3.5 although premium is recommended.

I personally find 95 to be the sweet spot on both my pajeros.
E10 gives me horrible economy, 91 isn't much better and 95/98 I get the same so the extra few cents a litre for me isn't justifiable. I do put the 98 in now and then as it's meant to help clean a little better then the other fuels but since I can't see the inside of the fuel tank etc etc I'm just taking their word for it.


As for the industries theory that Ethanol being a powerful detergant and E10 should keep everything cleaner, I find that utter garbage based on what I've been told by people who actually maintain and service automotive fuel systems and also the injectors and cyl heads I took out of the NK after just half a tank of E10.

[Superforg]

Ok so some updates on this.

When I had purchased the car it only started and drove on gas because the fuel pump had died. It returned about 12-13.5 liters 100k on gas on the run home at 114km/h.

When I got it home I pulled the tank and sure enough it had about an inch of red sludge in the bottom. The fuel filter actually had clay in it. The pump was fubar and looked filthy.

So cleaned tank and put 98 in it. New pump in and a new efi filter. Serviced it and put a new air filter on it.

Ran sweet and got 14ishL/100ks with my wife(lead foot) driving around town. Thought sweet. its on the money for a heavy 3.5l auto bus. Then a week later tried to do gas vs petrol test to see what was more economical around town. Gas got something like 26l/100k. Thought bugger that. Its good on long runs so will just use petrol. Then petrol blew out to 24/100k or something. So replaced O2 sensor and still no bloody change.

So once I drove it up to townsville to see the folks I though bugger this. Booked it into GAS guys to have a look because when I tried to run it on gas on the way here the 'full'tank I had topped up a week earlier and not used was showing half and it couldn't drive under power. Could only idle. So I thought, yeah its
.

They tested the O2 sensor and the brand new one isn't throwing a signal. So it's been running limp mode the whole time.

So gonna replace the O2 sensor again and make sure its working and do a gas leak test. Because I believe it's leaking gas on account of it smelling like an unlit bbq in the engine bay.

Will let everyone know the outcome tomorrow. LOL


Am hoping just a knackered new O2 sensor and something simple gas related. Moving to QLD, being made redundant from FIFO job and having a 3 month old baby means I don't need to keep throwing money at it like an upmarket stripper.

[redrock]

I'm concerned as well, I had really bad economy, I changed the timing belt, fuel filter, o2sensor, cleaned maf sensor. It seemed better. I drove to Adelaide on Friday, filled up the long range tank, $200. Had a 6x4 trailer, with three go karts. I put in $199.10 dollars @54.7 cents a liter, I only got 715 Kim's out of the tank. Filled up before leaving, $220 @ 59.9 a ltr towing a trailer back with a small compressor on it and a mig welder in the back I've managed 825 Kim's . Is there something else I need to check or do coz it seems a bit thirsty, I would appreciate any input

[Downunder35m]

Not 100% sure how helpful it is but since the fuel consumption these days means a lot of money:
As mentioned earlier a clean system is the first step to make sure the car runs well.
This starts at the pump, over the filters and down to the injectors.
After that a proper tune up is recommended as with all those sensore today it is just next to impossible to do it properly in your garage - unless you have all the right equippment.

But once that is all done it is down to the individual
Keep in mind our cars are heave and designed for a hard life!
I think a consumption of around 12L/100km is quite normal, over 14 or under 10 would be worth investigating.
When I started driving noone cared about fuel economy as fuel was dirt cheap, in fact most people that time had no idea how to check it other by comapring the fuel bills.
Later on I started to give "driving lessons" for friends so they can learn to use their car with often quite a lot less fuel usage.
For example: I towed my friends boat to Apollo bay and used around 13.5L on the run down, my friend offeder to do the drive back as I was stuffed and he used almost 20L forcing us to re-fuel close to Melbourne.
But I have to say he was used to his automatic Patrol....
You see the only difference was the driver.
If you use around 12L on the freeway but much more during city runs it might be a wrong driving style.
Bit hard to do it dry but I'll give it go based on the experience with my car:
Try to look ahead: Often you just got to the 60 only to stop at the next lights a few m ahead. Try to accelerate moderate and let the car use the momentum insteaf of staying on the throttle until you need to break.
Shift wisely: It is not a Barina and not a sports car! Accelerate moderate, keep the revs low (without starving the engine of course) and shift early.
If you have an automatic try to work out the best acceleration so the box shifts properly and the revs stay down.
When towing or with a heavy loaded car, keeping momentum is the key to keep the consumption down!
If you know you have to speed up to make it over the next hill you are already doing it wrong
Unless right at the limit our engines are capable of towing quite a lot without starting to struggle - if they do they also use shitloads of fuel.
Keep the revs uphill at the perfect range, on my diesel that is between 2000 and 2500 revs.
Being down to 2000 at the start of a hill means it is best to shift down and take it slower.
Same for traffic. Try to keep the rig going. If you aproach a light that is already red (or was green for a long time) let roll out early so you have a chance to keep going without a full stop.


Last one:
If all sensors are working fine, the filters are clean and consumption still goes through the roof, consider a proffessional tune up and to check/reco the injectors.
There are ways to perform a DIY check but comparing the spray patterns of your injectors. Might be worth to look it up if all other options are exhausted.

[redrock]

I have also changed filters and was towing a full trailer so at times it was hard to keep the revs down goofing up hills, but I used the cruise control to keep the speed steady for best fuel economy

[Superforg]

No driving style change. Getting 14l/100ks around city one week to getting 24.6l/100ks or whatever it was isn't my driving or miss lead foots.