Steps to improving fuel economy

[XRated]

As most of us know, the fuel consumption in the 4.0L I6s isn't the greatest in stock guise. However, I've noticed quite a few people have higher than average fuel consumption, myself included.

What I want to know, is what things people should be checking/replacing/fixing to try and improve their fuel economy, and what should be done first (ie. in order of cheapest & easiest, to more expensive & harder). For example, a simple check might be basic service items such as air filter, plugs and leads, compared to changing something like the O2 sensor or going as far as "a manual is much more efficient than the equivalent auto" or "get a custom tuned chip to adjust Air:Fuel ratios" etc.

Of course we have to consider that some people are a bit more "spirited" in their driving and/or do lots of city driving, so I don't expect miracles!

Mine is currently 17.7L/100km :O I am trying to get that down back into the low 14s like it once was. I know someone (with a Brock?) on the forums has a very low consumption per 100km (11L/100km I think).

Currently: ED 4.0L I6, 4 speed auto, regular unleaded, with the occassional tank of premium, 1004 114 Wade cam, 3.08 diff.

Cheers

[niko]

its called getting a manual 4cylendar 1.8litre lol

i have a mate with same setup but ef, with a el 5speed @ 100k's revs at 1650 lol! not taking it easy the whole time gets him 550 out of a tank? average of around 9/100

[Sundeep]

I went ape shit on my old car, in the end I converted to gas. You can't win!

I'd start with the following though;

-Rotor button, dizzy cap, leads, plugs.
-Air filter.
-Fuel filter.
-Test fuel pressure regulator.
-Test injectors to see if they are leaking.

I'd also be doing a fault test to see if any of the sensors are playing up. The most common ones to fail, resulting in bad fuel economy, are the Coolant Temp Sensor (CTS/ECT), MAP sensor, Air Charge Temp (ACT), o2 and TPS. The fault test isn't too hard to do, and it could bring up some surprises!

/gayness :P

Sundeep

[XRated]

Hahaha gayness.

Cheers Sunny. I've got a new rotor button somewhere, and I am getting a new dizzy cap, leads, air filter and plugs soon. Also going to attempt to replace the fuel filter..

BTW, on the trip computer I get the figures per 100km, but on my odometer, a full tank will [with luck] get 350kms these days (450kms months ago wasn't unheard of :P).

[Sundeep]

Yeah and the fault finding test stuff can be found in your Gregory's manual. All you need is a test light and some terminals, it's harder in the ED's than EA because of those tiny *** terminals.

I payed about $60 for plugs, Champion 8mm leads, rotor button, cap and NGK-R plugs for the EL. It made SFA difference to idle which I was hoping it would cure, but it made a noticeable difference to the fuel economy although it wasn't much.

/gayness.

Sundeep

[Polyal]

Well I haven't touched my car other than the exhaust, and I get 450 minuim a tank. This is mainly driving through Geelong peak hour after work (dont laugh it does get pretty busy, stupid trucks!).

What I find kills fuel economy is take off. Just take it easy, espically when in heavy traffic as your not going anywhere in a hurry anyway.

Also another little "trick" is when going down a long steepish hill just put the clutch in and roll as much as possible.

Little things I know, but it adds up.

[stockstandard]

Originally Posted by Polyal

Also another little "trick" is when going down a long steepish hill just put the clutch in and roll as much as possible.

lol - Mexican overdrive. Good in manual, bad in auto.

I get 14-15L/100k's and 400-500k's out of a tank. 5 speed and 3.08 diff helps. And now that my "spirited" driving has been replaced with "lets not wake the baby up" driving it should get a lot better.

When it comes to fuel economy the first step is to make sure everything is working right. As metioned above - plugs, leads, filters, are all good. Checking the computer for errors is good to. And making sure the car is regularly serviced - good engine oil, trans fluid, timing properly set, etc.

[niko]

i think there legality issues regarding rolling in neutral but meh who cares

[Polyal]

Originally Posted by niko

i think there legality issues regarding rolling in neutral but meh who cares

thats the craziest thing ive ever heard! Technically im still in gear, its just not engaged..lol

[EA2BA]

Dont drive around town in peak hour traffic, i used to get 18L/100ks - since moving to narre warren I am getting about 500 out of tank, so something like 13L/100k's , have also put in a new fuel filter.

[TUFED6]

My car has had amazing fuel consumption since 3rd gear went bang.

- John

[EA2BA]

using neutral in an auto is not supposed to be legal, yet i think it was today tonight promoted it as a way to save fuel.

[ilsautomotive]

Originally Posted by Dellboy999

using neutral in an auto is not supposed to be legal, yet i think it was today tonight promoted it as a way to save fuel.

That's a worry, having an auto in neutral for extended periods while the car is rolling would kill it pretty fast from what has been described to me. It creates extra heat because the trans fluid isn't circulating properly or something.

The best driving tip I have for fuel economy is to keep a decent distance from the car in front. Often you'll find the guy ahead of you will brake, accelerate, brake again etc and you can practically coast along the whole time and keep up - not to mention it is much safer. Having a 1.8 doesn't hurt either.

[ned]

I wish you good luck Luke, as you know about my problem now, me and the mechanic swapped the obvious things over on mine last night and it still came up as running rich. But if you do have any luck, I'll gladly try it!

[Paris Hilton]

there's a big *** hill on the way to my school, steep as anything...i just put it in neutral and coast the whole way down (T5)...people say this is bad, why?

[Damo]

yeah i've hear that rolling in nuetral isn't too good for your gear box.

Polyal: do you actually keep it in gear with your foot on the clutch ? That can't be too good for your clutch. It's called riding the clutch. :P Like what people do at traffic lights instead of going into nuetral than back to 1st.

[Polyal]

Originally Posted by Damo

yeah i've hear that rolling in nuetral isn't too good for your gear box.

Polyal: do you actually keep it in gear with your foot on the clutch ? That can't be too good for your clutch. It's called riding the clutch. :P Like what people do at traffic lights instead of going into nuetral than back to 1st.

Um trying to remember, sometimes I might. But if I am in gear, with my clutch in then isn't the gear disengaged so there is no contact anyway is there?

I would say sometimes I will roll with it in gear and clutch in, and sometimes I will have it in nuetral, clutch out and roll.

I dont get that if the clutch is not engaged then how is it harming the 'box?

[EA2BA]

Originally Posted by Polyal

Um trying to remember, sometimes I might. But if I am in gear, with my clutch in then isn't the gear disengaged so there is no contact anyway is there?

I would say sometimes I will roll with it in gear and clutch in, and sometimes I will have it in nuetral, clutch out and roll.

I dont get that if the clutch is not engaged then how is it harming the 'box?

harmful refers to automatics, manuals are fine go for it.

[Johno]

jus wondering if da EA has a ACT sensor\ and if so,, where is its location? if u hav pics, plz post em...

[Inferno]

I do a lot of high speed driving, 80 and 100 zones.

I get about 680 out of tank, premium unleaded. I did have it down to 10L per 100k's when only going to work and back home, that was 25k there and back, so 50 and about 45 at high speed country driving in economy, now it's blown out a bit cos I have to drive through town, so I do about 90k's a day.

[NZ]

selekta: you'd use the same amount of fuel by using no throttle and using engine braking as you do coasting. plus you don't need to wear out the brakes as much.

i think another important factor just as important as a well tuned car is driving style.

[EFFalcon]

any sort of chip that can handle ur ignition timing and fuel mixtures...
once we go playing with cams we really screw our economy :P
its bad enough @ stock!

[niko]

brakes are cheaper than clutches but karl

[CruizinEB]

My fuel consumption is in the low 14s, toget that i just use premum all the time (It cleans the carbon from the engin)

[RG]

Try replacing the hego (oxy?) sensor... the one in the exhaust just before the cat. Made a world of difference in mine.

My fuel economy went out the window, and I was advised that a carbon build up can lead to unburnt fuel. This then causes the 02 sensors to pick up not enough fuel, meaning the computer pumps even more in. A good carbon flush and in my case injector clean ($85 dollars for all 8) put my car back to normal, and even made the exhaust quieter. I also agree with Kylebradshaw1 that Premium or Ultimate fuel will increase your fuel ecomomy, more than off setting the extra price you pay for the fuel.

[spope]

"Riding" the clutch actually means when you have the clutch pedal partially pressed - clutch slips, creates excess wear.
If your foot is on the clutch pedal then it's completely disengaged, no contact between clutch plate and flywheel, so no wear. And it does no damage to the box, manuals are designed to do this. Nothing wrong with engine braking either, you just gotta know how to do it. ;)
Very bad to drive in neutral in an auto, for a few reasons, first being not enough fluid will circulate, and the other is the potential damage to internal components, as the rotation of the driveshaft will cause parts to spin, as opposed to being turned by engine torque. Not good.
Not really neccessary either, if you are coasting in an auto then your torque convertor should be close to maximum slip anyway.

Back to the original question though, have you checked your manifold for leaks? 2 of my manifold bolts were loose, caused me to use excess fuel - tightened them up, no probs. Some points to consider - the pcv system, map hose, and isc gasket. Because of the dodgy map sensor setup, the slightest leak will cause the ecu to pump in more fuel.
And check the oxy sensor too. If it's black and crusty, consider replacing.

[Psycho Chicken]

If you keep the revs up more than enough oil will circulate.

[mcflux]

Originally Posted by Psycho Chicken

If you keep the revs up more than enough oil will circulate.

... so chasing a mate down in traffic, pulling alongside him, putting it in N and punching it to 6k is OK then? :

(making sure the revs are somewhere around 1500 when I put it back in D) :P

[InitialD]

well my average was like 16.7 with good working injectors, etc...

I put new NGK "XR" spec sparkplugs in today and my average went down to 15.3

Im going to also change the O2 sensor over soon and see if thats my hassles...