If we switch to Premium fuel, Do we need to reset the ECU?

[Poeter]

Hmm, i filled my tank with bp ultimate when i had about 1/5 of fuel left on the gauge and i'm getting a fuel consumption rate of 7.9L for city drives.

My car is a vti-s manual. Still running in as it has 500km on the clock.

So i'm a bit disappointed with the consumption.

I read some other forum mentioning that some cars needs to disconnect their battery to reset the ecu and the ecu will retune itself for the octane level of the fuel.

Would i need to do this for the jazz? Or does it retune itself accordingly to some oxygen sensor?

PS, is it wrong to refill a tank which supposedly was regular fuel and still having 1/5 of it left? Or do we really need to wait til the low fuell warning light to appear to switch to premium??

[TypeG]

it depends how u drive mate
for reset ECU, i am not sure but i havent done that

just refill since u cant wait till yr tank is empty
LOL

[Poeter]

Well, my driving style, i only just learnt manual not long ago since i never got any professional help.

But anyway, i generally shift about 2k - 2.5k from 1st gear, 2.8kk from 2nd and i generally stick on 3rd gear while doing 60km/h which sits at 3k rpm. I would shift to 4th if the speed limit gets to 70. But for 60zone, i stick to 3rd most of the time since the traffic varies at times.

[muli]

i dont really understand why one would need to reset ECU if the ECU normally adjusts things anyway when driving e.g so it dont ping like hell under load if quality of fuel is poor.

Some ppl swear by it, other disagree

[as001]

once the engine runs in you will get better fuel consumption but sounds like you may just need to sit more in 4th gear then 3rd cos your engine will be under less load even though the sitting on 60km per hour, give it a go to see if it makes a difference

[Geoffy]

Try it for a month and see... can't base it all from one tank...

I average 600kms on BP Ultimate... I didn't do anythin to my ecu or whatever... I just switched from Optimax to Ultimate... I too have VTi-S Manual

[ahcash]

Well, my driving style, i only just learnt manual not long ago since i never got any professional help.

But anyway, i generally shift about 2k - 2.5k from 1st gear, 2.8kk from 2nd and i generally stick on 3rd gear while doing 60km/h which sits at 3k rpm. I would shift to 4th if the speed limit gets to 70. But for 60zone, i stick to 3rd most of the time since the traffic varies at times.

IMO, try to use 4th gear on the 60km/h so that it sits at about 2000rpm or less.. See how you go with that... I think it will reduce your fuel consumption.

I am on Auto VTi-S and doing at 7L/100km with Ultimate... Now trying Normal PULP (RON95), don't have to reset ECU... also, don't muck around with the battery if you don't know what you are doing .. (like me)... :D as it might affect other stuff, such as airbag, radio etc.

[FB008]

i do 60 km/h in 5th gear

if you want really good fuel consumption, sit at 90km/h on the motorway for a while. i managed to get it to 4.8l/100km for doing 70km :D

right now my city fuel consumption is about 5.2L/100km using PULP. but i'm cheating a fair bit and clutch coasting pretty oiften, coast to the traffic lights :p don't do it unles you're confident and know what you're doing, you don't want to screw your brakes too much!

no idea how to reset the ECU, dont know if i should bother?

[Geoffy]

I never rev over 2.5... Cause once vtec kicks in it rips ur petrol in half... I only vtec on weekends...

[MRFIT]

I found from my recent trip away..... I mixed ultimate with normal unleaded..... and the consumption has dropped down to 5.8L..... compare to my normal 6.9L......

strange..... :)

[Kandy]

I found from my recent trip away..... I mixed ultimate with normal unleaded..... and the consumption has dropped down to 5.8L..... compare to my normal 6.9L......
I don't have the same car as you do, but if your trip away involved country- or non-city driving (less stop/start, traffic light, slow fast etc etc) your fuel ecconomy would be much better as I think alot of petrol goes into launching the car rather then keeping it at constant speed, so it may not have much to do with mixing ultimate and normal.

[MRFIT]

I thought about that too, but after I got back to the city, I still have half a tank left, and I've been driving to work for 3 days, and its still only showing 6.1L..... :)

oh well......

[pornstar]

disc ur battery wont do too much, i havent had a chance to take a close look YET, but if u guys also have 2 o2 sensors one before and one after the cat, the af ratios will usually remain stable, reset or not.

Poeter, i have had 3 or 4 ppl come to me with the same things as u, what i generally find is that being new to manuel, they have poor throttle control, this leads to a poor fuel mileage. Even if u never shift over 3k rpms, there are times that a better driver can consistently shift at say 4k rpms and still have better fuel economy.

Try this, when u next have a stand start acceleration from say a traffic light, see how heavy u depress the pedal, if its more than 3/4 try take it back abit, ull find this relaly helps heaps.

[Poeter]

hmm 3/4 depressed, i never done that before. Wow, wouldn't that rev the engine heaps and give great stress to the clutch when go from stationary.

i only take about 1/5 or 1/4 of the pedal depressed when accelerating from stationary.


i think it revs to 2k Rpm when i do that but i do try to keep my throttle control as light as possible.

I go through this road with heaps of humps for every 100m and i couldn't be bothered shifting down 2nd and accelerating then shift to 3rd again.

So, i stick on 3rd for these humps and i do realise if i pressed the accelerator harder, my car ain't gonna accelerate much fast. so when i accelerate from the humps in 3rd, i depress about 1/5 of the pedal.

[Catcha]

hmm 3/4 depressed, i never done that before. Wow, wouldn't that rev the engine heaps and give great stress to the clutch when go from stationary.

i only take about 1/5 or 1/4 of the pedal depressed when accelerating from stationary.


i think it revs to 2k Rpm when i do that but i do try to keep my throttle control as light as possible.

I go through this road with heaps of humps for every 100m and i couldn't be bothered shifting down 2nd and accelerating then shift to 3rd again.

So, i stick on 3rd for these humps and i do realise if i pressed the accelerator harder, my car ain't gonna accelerate much fast. so when i accelerate from the humps in 3rd, i depress about 1/5 of the pedal.

Hope i'm reading this right, but not being in the optimum gear for you speed will also affect fuel consuption, like what you explained you should be 2nd not 3rd :D