Poor fuel consumption FZJ80 (1 Viewer)

[aboudimaysi]

Hey guys! New to the land cruiser scene and wanted some advice! I've recently purchased an 80 series and am learning all new things about the car on a weekly basis. As of now I'm getting about 330kms to a full tank (subtank removed by previous owner for own reasons) and the car is running rich. After I replaced the air filter it had begun to run more rich than before, is the fuel mileage normal? And if not what can be done to help with the mileage and the car running too rich? Thanks for any help!

 

[dsmud4u]

Everyone with a cruiser should be used to poor mileage. Unless you’re getting something abysmal like 4-6 mpg, I’d say everything checks out.

 

[Tachycardic]

It depends on how your truck is configured, the condition it is in, and how you drive it. If it is stock and you're doing at least 50% highway driving, you should be getting about 370-390km when your low fuel light turns on (at 5-ish gallons/19-ish liters of fuel left). That's based off my experience as my stock truck travels about 385km before the light comes on and the furthest I've gone on a single tank is 470km.

If you're kitted out with armor, roof rack/roof tent, and bigger, and more aggressive tires, I'd say that you're on point.

 

[aboudimaysi]

It depends on how your truck is configured, the condition it is in, and how you drive it. If it is stock and you're doing at least 50% highway driving, you should be getting about 370-390km when your low fuel light turns on (at 5-ish gallons/19-ish liters of fuel left). That's based off my experience as my stock truck travels about 385km before the light comes on and the furthest I've gone on a single tank is 470km.

If you're kitted out with armor, roof rack/roof tent, and bigger, and more aggressive tires, I'd say that you're on point.

Hey thanks for the reply, as of now it's completely bone stock, I'm yet to lift it and or bigger tyres which is what's left me confused in this whole situation, I thought maybe it could've been the o2 sensors considering the vehicles age but that's just a thought for now, I also have an issue with my fuel gauge giving off false readings. It'll be all the way down at the empty line but keeps driving no issue for another good 60-70 until it just breaks down, luckily I hold a 20L Jerry can with me

 

[Tachycardic]

The simplest thing you can do is to clean out your air filter, or get a new one, make sure your oil level and your tire pressures are optimal. Check your intake hose to make sure there are no cracks--pay particular attention to the accordion section. You should have a grease gun and make sure you appropriately lube your U-joints and slip yoke. You should make sure that your cooling system is in good condition. Other than that, you should ensure that your vacuum hoses, spark plug, cap/rotor/wires, are all in good condition.

Could you have issues with your 02 sensors, a crack in your main tank, an ECM issue, injectors that need servicing? Sure, but check the easy baselining stuff first and go from there.

 

[LandLocked93]

I could get about 18mpg on 265/70-16s, 3" lift, front bumper and winch, but unloaded otherwise at 65mpg on flat ground for 90miles.
Full tank @70mpg would get close to 300 miles a tank, w/o a lift, still unloaded.
On the trail @ full loadout is about 1.2 gallons per hour (~9mpg on average)
In short, agree with others who say your numbers sound about right.

Also agree with others that O2 sensors are a good place to start, barring obvious issues with other things.

 

[robnicko]

does your 80 have O2 sensors as many in Aus do not? What year model & engine type?
They utilise a pre determined map in the ECU which relies upon MAF & coolant temp sensor readings to adjust. The only other item is the Co2 adjuster at the bottom of the air filter housing however my understanding is you need a special tool to adjust it and a Gas Analyser machine to read the exhaust pipe whilst doing so

other than that make sure your air pressures in your tyres are good and the way you press the skinny pedal influences consumption alot.

 

[LandLocked93]

does your 80 have O2 sensors as many in Aus do not

If there are no O2 sensors, would that rig also be carbureted as well?

 

[robnicko]

If there are no O2 sensors, would that rig also be carbureted as well?

No, mines a 95 update model and no O2 sensors and MP injected

In AUS there was some exemption for these to be sold without O2 sensors and all the emissions stuff that causes headaches such as EGR

Until we are told what year model and engine type its a needle in haystack scenario.........

 

[AussieHJCruza]

Do you know how many litres per 100 km you're getting? If not, we can't comment on it being reasonable or otherwise.

Fill up with fuel, reset the odometer and then when you fill up again, note how many km, how many litres you put in, and calculate accordingly.

You'd expect to get high teens to early 20s litres per 100.

 

[aboudimaysi]

Do you know how many litres per 100 km you're getting? If not, we can't comment on it being reasonable or otherwise.

Fill up with fuel, reset the odometer and then when you fill up again, note how many km, how many litres you put in, and calculate accordingly.

You'd expect to get high teens to early 20s litres per 100.

so the most i was able to obtain was 330kms on a full 85 litres of 91 octane, for the meantime i only have the main tank as the previous owner removed the lpg tank for some unknown reason. after calculation im getting about 3.88km per litre of fuel which comes up to about 26L per 100 kms which i still think is horrible for the car not being lifted and rigged with all sorts of parts. for context ive got a 97 80 series with a 1fzfe, cheers

 

[robnicko]

so the most i was able to obtain was 330kms on a full 85 litres of 91 octane, for the meantime i only have the main tank as the previous owner removed the lpg tank for some unknown reason. after calculation im getting about 3.88km per litre of fuel which comes up to about 26L per 100 kms which i still think is horrible for the car not being lifted and rigged with all sorts of parts. for context ive got a 97 80 series with a 1fzfe, cheers

something definitely wrong there.
You should be around the 13-15 lt per 100km if all is right with the car dependent on how its driven
Can you post some some pics of the engine bay, in particular the intake as if it was previously on LPG there may be some changes between the MAF & Throttle body that could still be there. Also check the timing and see it its at 3Deg BTDC
Does it have a snorkel by any chance?

 

[aboudimaysi]

something definitely wrong there.
You should be around the 13-15 lt per 100km if all is right with the car dependent on how its driven
Can you post some some pics of the engine bay, in particular the intake as if it was previously on LPG there may be some changes between the MAF & Throttle body that could still be there. Also check the timing and see it its at 3Deg BTDC
Does it have a snorkel by any chance?

Hey thanks for the reply, yes she does have a snorkel and don't redline it every chance I get haha, I basically granny spec it and don't really exceed over 2k rpm, im usually within aus speed limits. I'm yet to take it on it's first 4wd trip due to this issue, I'll have a look at the timing hopefully tomorrow with a mechanic friend of mine. I'll attatch some photos to show how she's looking

 

[robnicko]

ok, I see a few hoses blocked off and the intake tube appears collapsed which probably collapses more when vacuum present therefore limiting air into the motor - fix these especially the valve cover breather that goes to the intake.

 

[ToothDr]

ok, I see a few hoses blocked off and the intake tube appears collapsed which probably collapses more when vacuum present therefore limiting air into the motor - fix these especially the valve cover breather that goes to the intake.

This. Why is you PCV valve hose capped?

 

[06reg4x4]

yea u need to get all them vacuum lines all back proper.

 

[Devils Paw 80]

And on an unrelated note: The driver's side of heater control valve looks discolored, meaning it should be replaced before disintegrating, causing a major coolant leak. The hose clamp on that side has been replaced while the other side looks original. What's up with that?

 

[Timpanogos Slim]

No, mines a 95 update model and no O2 sensors and MP injected

In AUS there was some exemption for these to be sold without O2 sensors and all the emissions stuff that causes headaches such as EGR

Until we are told what year model and engine type its a needle in haystack scenario.........

An EFI system with no o2 sensor would essentially be running blind.

The o2 sensors upstream of catalytic converters allow the EFI system to determine how fully the fuel is combusting so that it can adjust the air-fuel ratio to get closer to the ideal 14.7:1 without running too lean.

Without the feedback, it's running without a feedback loop. What is referred to as "open loop".

Since running too lean will destroy the engine but running too rich won't, the open-loop program typically runs rich. It also tends to retard timing but i assume you have knock sensors so perhaps the ozzy ecu doesn't do that to you.

The o2 sensors downstream of the catalytic converter exist entirely to determine if the catalyst works properly.

 

[LongDuck]

My wife-unit got me this for Christmas in my stocking. Seemed appropriate...

 

[manofthewoods]

An EFI system with no o2 sensor would essentially be running blind.

The o2 sensors upstream of catalytic converters allow the EFI system to determine how fully the fuel is combusting so that it can adjust the air-fuel ratio to get closer to the ideal 14.7:1 without running too lean.

Without the feedback, it's running without a feedback loop. What is referred to as "open loop".

Since running too lean will destroy the engine but running too rich won't, the open-loop program typically runs rich. It also tends to retard timing but i assume you have knock sensors so perhaps the ozzy ecu doesn't do that to you.

The o2 sensors downstream of the catalytic converter exist entirely to determine if the catalyst works properly.

Good contribution above. And, I always thought (incorrectly) that the air to fuel mixture was 14.1:1 this old dog needs to learn a new trick.

Happy holidays