VS V6 UTE Fuel economy 20L/100km PLEASE HELP

[altaaf]

hi guys,

i have a vs 99 v6 ute which has a shit fuel economy...18-21L/100km overall i only get 250-300 km out of 1 tank with premium fuel....
i fixed the earth issue
new oxygen sensor
no error code comes up
i ran efilive v4 to check all the sensors
i was getting +/-1 for oxygen sensor


please help

[The1]

post up a log? have you checked error codes?

[altaaf]

whats a log? im new to this
yes i have done a scan i had code 64 and 74 but after i put new o2 sensor and cleared the code nothing has came up for 2 weeks now...

[The1]

while logging with efilive hit spacebar and this will record, then once you stop you can save the logged data to a file, if you post this up or email it to me pm, i can have a look.

[Morton]

I would be curious. Unload everything except your spare tyre, pump up all your tyres to 38psi, and get out onto the open highway. Fill her up with your choice of fuel. Drive 50km away, turn around, and drive 50km back to the same servo. Fill up and note how much you put in.

This will give you a more accurate idea of how far from "norm" your fuel economy is.

Then you can start working on things like spark lead resistance, spark plugs, old oils and filters, and your heavy right foot. ^_^

[altaaf]

ok i will do that 2moro at pm cheers.

[altaaf]

i will do the run on the weekend, it basically has new spark lead, spark plugs, old oils and filters all put in a week ago...
so do fill the tank up to the brim or just up to the first click?
i did a trip on the highway last week i got 430km out of a tank=57L fuel was used
with 150L i got 1197km on open road.

[Morton]

So on the open road you got 12 to 13 litres per hundred. That's not really TERRIBLE. Is this thing auto or manual? Any modifications? Were you carrying much load?

Don't trust the "litred used" on your trip computer as gospel truth, it can often be inaccurate. Always trust how much fuel you put in at the next servo stop.

You can fill it up to the brim if you want, but I just use first click. So long as you use the same method every time, you'll get a reasonably accurate reading.

If you want to throw a few dollars at the car in the hunt for some more economy, get a new coolant temp sensor (the two-pin sensor if they ask which one), new manifold temp sensor (they're not that dear any more), and a new throttle position switch. Should set you back in the order of $150, which isn't bad since they will probably need replacing at some point anyway.

What sort of oil are you using?

What temperature does your car tend to run it, has a cooler thermostat been fitted? Reducing the running temperature of your car can also adversely affect fuel economy.

I think you could recover most of your fuel economy using good driving habits, like gaining speed on downhills and allowing your car to lose speed on uphills. Coast for as long as possible before a known stopping point, but most importantly just try to keep your engine load consistent.

Keep in mind that any increase in speed above 80kph is going to be exponentially reducing your fuel economy, so if you're belting down the highway at 130kph expect bad results. Air drag is the number one killer of fuel figures.

If you want to get really stuck into it, you can buy tyres with less rolling resistance, fit lighter wheels, lower ratio highway diff gears, throw a good toneau over the ute canopy, and begin to fiddle with undercar air effects if it really interests you.

With a few simple mods I was able to get 8-9 litres per hundred on the highway out of my V8 Statesman, which is a heavier car than your ute.

[Morton]

Example:

[altaaf]

hey the1 i tried to upload the file but it fails do u want me to email it to you...

[ute boy]

might sound dumb but if u run 98 all the time try runnning 91 and see how it goes. i get about 450km out of 55l on 91 but if i go 98 i drop down to 300 mainly because it burns easiler and i sorta got a lead foot sometimes =P

just giv it a try and let us know

[Not_An_Abba_Fan]

The VS was not terribly economical, despite it be the first Commodore to be fitted with the "ecotec". 18-20L/100 around town is pretty average for them. 10-12 on the highway is what they get too. The biggest killer of town economy is an aftermarket larger exhaust system. Sure they sound OK, but they adversly affect the economy.

Without sounding cold, you will just have to live with it.

[RX25SE]

FYI my VS gets about 13L/100km around town no probs, and will go as low a 8.9L/100km on the highway.

Bog stock.

[ute boy]

FYI my VS gets about 13L/100km around town no probs, and will go as low a 8.9L/100km on the highway.

Bog stock.

manual???

i average about 13l/per100 on an average tank
bout 11ish on northen road ( highwayish farly widey but consistant
mines auto also

[RX25SE]

manual???

Auto...........

[altaaf]

i have tried 98 fuel but i got 250km out of a tank and now i normally use 91 fuel.
its a v6 auto
i have a redback performance exhaust with straight through tail pipe
i have a bit of a heavy foot sometimes... :P

[The1]

hey the1 i tried to upload the file but it fails do u want me to email it to you...

have pm'd you.

[altaaf]

i have tried the fuel i get only 250km on 98 fuel and i get 300 to 330 km on 91...
lol i got a heavy foot sometimes... :P
its got a redback performance exhaust with straight through tail pipe
its a vs v6 auto

[altaaf]

have pm'd you.

i have sent it just now
cheers

[The1]

from the logs you just sent me the left 02 sensor (passenger side) is dead, sit's on 800mv (Rich) and doesn't move, and in the other log your Radiator fan is coming on and off and the coolant sensor was only reading 40 deg C, either there's a loose connection to it or it's faulty and needs replacing.

[altaaf]

from the logs you just sent me the left 02 sensor (passenger side) is dead, sit's on 800mv (Rich) and doesn't move, and in the other log your Radiator fan is coming on and off and the coolant sensor was only reading 40 deg C, either there's a loose connection to it or it's faulty and needs replacing.

i had a dead left 02 dead sensor that i have replaced and i had the aircon on this morning i will send u a log which i got this afternoon but i had the aircon again i also have a 81 degree thermostat ....
its on its way now

[The1]

all looks fine in that new log, good cross counts on the o2 sensors, coolant temp sensor working, fueling is spot on LTFC, i would recommend getting the memcal tune updated for 81 Deg Thermostat. Either way your fuel econ should get better now with those fixed up.

[altaaf]

thanks man

where will i get a updated memcal???
please advise

[vsv6dude]

all looks fine in that new log, good cross counts on the o2 sensors, coolant temp sensor working, fueling is spot on LTFC, i would recommend getting the memcal tune updated for 81 Deg Thermostat. Either way your fuel econ should get better now with those fixed up.

How do you retune the memcal for the 81 deg thermstat ?

[Krilnik]

Best economy I've achieved is 14.44 L/100K's. That's in city traffic morning and afternoon and a very light foot. I never let the revs get over 2000rpm.

I have cleaned the MAF and will be changing the fuel filter very soon.