2.4lt petrol engine fuel hog....why??

[Hilux Hetti]

Hi All.
I recently did an economy test on my 97 carburetored 2WD Hilux and I was shocked at the lousy figures. 280klm for 49 litres of fuel?? That's only 16mpg or 17.5lt to the 100 klm.

Several forums I read suggests that's about all you can expect out of a Hilux with the 2.4 carby petrol engine. One guy even said that many have tried to improve the economy and there's just nothing you can do about it except to learn to live with it.

Since my Hilux was bought as a private workhorse, I guess I'll just have to "learn to live with it" but what is it that makes the 2.4 petrol such a thirsty beast? Is is as basic as the gear ratios? Perhaps the carby was made for power and not economy, or is it the geometry of the engine that's the problem??

I never expected to get great economy out of it, but I did expect to get a little more than 16mpg! And yes, I'll do all the usual stuff like filters, new plugs, timing etc, but from what I've read on sites all around the world, that particular engine was always a hog and nothing will change it except for very marginal differences. What I really want to know is why this engine is particularly thirsty??
Cheers,
Hetti

[river]

Hi,

Old style engine, with carby, dragging around a pig of a chassis with low gearing.

Says it all.

seeyuzz
river

[tomvale13]

but what is it that makes the 2.4 petrol such a thirsty beast? Is is as basic as the gear ratios? Perhaps the carby was made for power and not economy, or is it the geometry of the engine that's the problem??

My money is on engine geometry.

[Dazza]

Wow thats worse than my 4x4 hilux with a 3Y 2 litre engine. i average 17 litre per 100 klm. I thought a 2wd would be better on fuel.

[random]

Is it auto or manual?
My 22r 4runner (4wd) used to get around 14-15l/100kms which I thought was bad
After converting it to EFI, I now get around 13l/100kms... still worse than my 6cyl cressida.

[thechuckster]

better diff would be a good start (tho as a farm vehicle it might be less than good).

A clean breathing engine will also help (like lots of fresh air to the air filter, a decent sized filter).

Also, check that the auto-choke is actually working - they tend to fail in the cold posistion. Replace and manualize it.

Also consider what tyres you are running (try to choose for use so road/car tyres if mostly on the highway and keep the h/d truck tyres for when you need them) and also remove unwanted crap from the tray and body (less weight is always a good thing and even removing stuff like ladder racks will help as it's less wind resistance). Lots of 1% improvements will add up.

[Hilux Hetti]

Is it auto or manual?
My 22r 4runner (4wd) used to get around 14-15l/100kms which I thought was bad
After converting it to EFI, I now get around 13l/100kms... still worse than my 6cyl cressida.

It's a 5 speed manual. I kind of expected a 5 speed driven like grandma might pick up at least 12l/100kms, but not even close!!

[Hilux Hetti]

better diff would be a good start (tho as a farm vehicle it might be less than good).

A clean breathing engine will also help (like lots of fresh air to the air filter, a decent sized filter).

Also, check that the auto-choke is actually working - they tend to fail in the cold posistion. Replace and manualize it.



Also consider what tyres you are running (try to choose for use so road/car tyres if mostly on the highway and keep the h/d truck tyres for when you need them) and also remove unwanted crap from the tray and body (less weight is always a good thing and even removing stuff like ladder racks will help as it's less wind resistance). Lots of 1% improvements will add up.

A conversion from auto to manual choke is a good idea. At least I'd know for sure it was off, although it does seem to be working ok and goes off fairly quickly. I was thinking of replacing the stock air cleaner with a bigger one. That's got to help, but I really feel the biggest piece of the equation is the gearing ratios. One of my shift managers had an earlier petrol Hilux and he had to fill it twice a week just to drive the 12 or so klm to work and back and that was mostly open road driving. He traded it on a slightly later model 4x4 Courier and halved his fuel bill. His diff ratios are about the same, but the fifth gear is much taller.

Also, it's not carrying a huge amount of extra weight and currently running car tyres. I'm going to try 15in wheels and winter treads as I need it to get into various wood lots and see if it makes any difference before going any further. I really like it in every other way and won't be trading it on a Courier just to pick up a bit of extra economy :-)

[maccac__1590]

a bloke at work put a webber carby kit on his 4runner, like thoes on ebay, and he reckons he got a fair bit better economy, he also had extractors and got it all tuned buy some carby guru, i get like 10-11L/100 in my 22re corona sometimes a bit better, that's with 98 octane fuel and 50 psi in the tires thoe hahah

[Youngy]

I recently rebuilt my carb and the economy has improved a great deal. Still not super though.

I am converting to an Celica sourced 22RE very soon - be an interesting comparison

[4th surf]

Hi Hetti

I think that I mentioned in another thread that you needed a carby kit and a damn good tune up but while these things were never known for the fuel economy what you are posting is V8 Hilux/Surf territory and that is where the temptation to give it a bit of "loving to the loud pedal" due to the V8 sound or give those tossers in V8 Commondores or Fowlcans a bit of a fright is hard thing to resist. You should be getting around 400km to a tank on 4.88 diffs with 31 inch tyres with "normal" driving. One thing that I did neglect to mention which I did on another thread unrelated to Hilux is to check the oil and give it the "Sniff test". If the oil smells a bit "Petrolly" then a new fuel pump is in order as the diaphragm may be leaking filling the sump up with petrol which may also explain some of the other problems you've been having

[Hilux Hetti]

Hi Hetti

I think that I mentioned in another thread that you needed a carby kit and a damn good tune up but while these things were never known for the fuel economy what you are posting is V8 Hilux/Surf territory and that is where the temptation to give it a bit of "loving to the loud pedal" due to the V8 sound or give those tossers in V8 Commondores or Fowlcans a bit of a fright is hard thing to resist. You should be getting around 400km to a tank on 4.88 diffs with 31 inch tyres with "normal" driving. One thing that I did neglect to mention which I did on another thread unrelated to Hilux is to check the oil and give it the "Sniff test". If the oil smells a bit "Petrolly" then a new fuel pump is in order as the diaphragm may be leaking filling the sump up with petrol which may also explain some of the other problems you've been having

Sorry for the late reply. Been busy the past few days. Checked the oil and did a "sniff test" but it's just smells like well used oil. That gets changed next week anyway. The carby kit is happening, but I haven't really rushed into that simply because I'm not using the Hilux much at the moment. Ive started another economy test on it and have been keeping the speed to 90kph. So far I've done 99k's and the gauge has dropped back to 3/4 which is good if the last half of the tank doesn't go quicker, which most cars do because of the shape of the tank. Unfortunately, I'll bugger it up Thursday as I have to go and pick up two round bales of straw. One on the back and one in the trailer, but it will be interesting to see how the fuel gauge holds up with a load on board.

Anyway, thanks for the suggestions. I'll keep plugging away at it.
Cheers,
Hetti.

[Dazza]

Have you checked to make sure your speedo is accurate with the car tyres on it instead of the light truck tyres that it originally had. Most car tyres are not as tall as light truck tyres so your sreedo will show that you have travelled more Ks than you have actually done.

[lexsmaz]

Also make sure that the ignition timing is correct & you are getting Mechanical advance from the distributor, but more importantly check that the Vacuum advance is working as the vacuum advance main purpose is to improve fuel economy on light throttle cruising ..

[Hilux Hetti]

Have you checked to make sure your speedo is accurate with the car tyres on it instead of the light truck tyres that it originally had. Most car tyres are not as tall as light truck tyres so your sreedo will show that you have travelled more Ks than you have actually done.

Good point Dazza. It does have car tyres on it and I've noticed that when I go through a highway speed test area it says I'm doing 5kph less than the speedo is reading, however if my odometer is showing more miles than I've actually done, wouldn't that make the economy appear better than it is in reality?? In other words, if the speedo showed 280k's (as it did) and it should have really been say, 250k's then that makes the economy even worse!!

However, I think there must have been a glitch in my reckoning or else the choke got jammed on for awhile or something because I've been driving it like grandma on the second tank (I only use it to haul stuff. My 1990 Seca is my daily driver) and so far I've done 200klm for just over 1/2 a tank. Now we all know that the last half of most tanks seem to go much quicker than the first half, so I'm not holding my breath, but if things stay on track, then I'd be looking at around 380k's to the tank and that's a significant improvement considering that last Thursday I was hauling a trailer with a big 5x4 roll of wet hay in both the trailer and the tray and it was very heavy. I must say though that the Hilux handled the load admirably. He does like to work!

I won't really know until I fill it up next week, but on the surface of things it looks as though a bit of careful driving combined with the right sized tyres (and I really do need some good light truck tyres) might make the old Hilux a keeper after all.