Fuel Consumption on 3.0

[GTbee]

I just filled up today and my latest reading is 14.95. This is suburban, mostly shortish trips with aircon on around 25% of the time. Car is mostly driven fairly sedately which means the most I rev it to is up to 4.5 to 5k.

The car was recently serviced and a new air filter installed.

Given the above I'm not that happy.

I do reckon it needs a good dyno tune as the engine does seem to have that flaky bottom end power delivery that many people complain about. And sometimes I do punch it a little bit to get it moving more quickly when moving away from the lights etc.

I've got new suspension as well as insurance and rego to pay for, so I''ll have to leave any tune for next year.

[I Wish]

How far are your "shortish" trips?

[GTbee]

Driving to the train station 8 km each way during the week (yeah I know it's not the best thing for economy but apart from a couple of lights it is a generally a free run) .

And 30 km+ on longer trips (but usually still suburban) during the weekend.

[JJYL]

I can barely manage over 300km/tank with sensible city driving, never rev pass 6500rpm

Somethings is wrong with my 3.0R, considering what other owners are achieving in this forum

this worries me

Have you had it tuned?

Servicing up to date?

Has the airflow meter been cleaned?

Yeah the car is tuned, serviced up to date with spark plugs and all that changed less than 2000km ago

No, air flow meter has not been cleaned, would cleaning it have a dramatic impact on fuel economy?

[Tradewind]

If the airflow meter was extremely contaminated it could have a substantial impact on the fuel Econ

You had the vehicle tuned as in had new ECU data flashed in?

For economy driving I don't rev engine past 3500 if I can help it, the use rate of juice increases heaps with any extra RPM

[JJYL]

Yup, ECU data flashed in

I don't rev the car, baby most of the time as the 3L gives me enough torque down load to get around town

Some people told me try resetting the ECU, let the computer learn my style of driving

but compared to what others are getting, my fuel econ is shocking

[I Wish]

It is your short trips and right foot that are killing your fuel economy.

I used to average 13.5-14.0 before I molested my vehicle.

My drive to work was around 5Km. Oil didn't even have time to warm up.

[JJYL]

No, I always stay below 3500rpm

[Robbks]

i'd be looking at 02 sensors and coolant temp sensors first
mine averages 11.5-12 L/100km on city only, my trip is only 8km to work

[scottb721]

I have a 70klm round trip to work each day. No traffic lights and mostly 80/90/100.
Averaging low 9s in mine.

[JJYL]

i'd be looking at 02 sensors and coolant temp sensors first
mine averages 11.5-12 L/100km on city only, my trip is only 8km to work

How do I know if the mentioned sensors are on there way out?

Or they should simply be replaced?

[Statts]

Just got back from a tip Adel -> Melbourne and return. Inclusive of city driving at all 3 ends, the average for the whole trip was 8.8L / 100km. Was very happy with this, more power and more economy than my previous car (Holden Calais). For what it's worth, around town I average around 12.5. Work is 20-25min drive away in moderate traffic. I don't drive like a nanny and rev to around 4.5-5000 during normal driving.

[west_minist]

You keep saying your car is tuned. How was it tuned?

Also here is a list of stuff that can really affect fuelling:

1. Poor Fuel quality
2. Spark Plugs not Gap to Manual specs
3. Car over 60,000km using old AFR Sensors
4. Very Dirty Air Filter and MAF Sensor needs cleaning (right up inside the housing and not the little bulb you see)
5. Poorly operating Injectors. Injectors need cleaning
6. Very dirty Intake Header. Need professional cleaning
7. Carbon build up on the piston heads and valves, due to too much slow driving and maybe lack of service
8. Leaking valves. You should have an Engine Compression test on all 6 Cylinders
9. Leaking Exhaust Headers

I do hope the above will help you tremendously. If you have been driving you car slow for a very very long time and not going past 5000rpm, maybe its time you start doing so at least a few seconds once a day

[Farugah]

I have noticed that going much faster than 110kph affects the fuel consumtion quite a lot, where doing 130 will jump it up to about 12l /100kms does anyone know where the sweet spot is for fuel consumption v Speed?

[smythie]

I haven't noticed that with mine. 80km/h in 6th is still the best for consumption but past 100km/h and up to 150, it's pretty consistent on the same stretch of road.