Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

Still high fuel consumption after FULL SERVICE

Clovance

New Member
Joined
Nov 9, 2012
Messages
120
Reaction score
0
Points
0
Location
Townsville
Members Ride
VT Executive S2, built 1999, 3.8l V6
Hey guys,

This is a list that i did not long time ago:

Front brake pads changed (50$)
Spark plugs changed (36$)
Ignition leads changed (48$)
Fuel pump relay changed (10$)
Oil changed (30$)
Oil filter & sump plug changed (15$)
Air filter changed (20$)
Fuel filter changed (20$)
3 wipers changed (18$)
(16/03/2013, 212628km)

Oil diff changed (25$)
Trans fluid changed (35$)
Trans filter and gasket changed (30$)
(20/03/2013, 212674km)

- o2 sensors (both) replaced. Next time at 264685km (190$)
- maf sensor checked (looks clean) and throttlebody cleaned
(23/04/2013, 214685km)

And guess how high my fuel consumption is:
Around 20l/100km in city!!!!!

Ok my car is usually loaded but hey, i baby it ALWAYS and 8 liters more than it is supposed to use?! After all this servicing?!

On the highway with constantly 100km i get around 12 liters / 100km...

What else can i do!? Do u think it is worth to check the fuel injectors? How expensive are new ones or can i just clean the old ones?

Thanks in advance!

Cheers
 

Cheap6

New Member
Joined
Jun 19, 2005
Messages
2,498
Reaction score
74
Points
0
Members Ride
VP Exec
The dash is OK. It's useful to check them against what you are putting in the tank also. (Try to) use the same pump each time because differences between the pump cut off point and the slope on the concrete apron can affect the fill amount.

Maybe try having the EGR cleaned +/or checked.

Tyre pressures OK?

How loaded is "loaded"? Weight does have an effect on fuel consumption but you'd have to be well into the 10's if not over 100kg to really notice and it will have less effect on highway consumption. It's not going to be +50% anyway.

Engine or trans. oil overfilled?

Slipping trans. or dead/dying TCC?
 

Tree cutter

Tree cutter
Joined
Apr 15, 2006
Messages
1,020
Reaction score
8
Points
38
Location
Mt Gambier SA
Members Ride
VX Calais SuperchargedV6
Is the engine warming up properly? If the thermostat is stuck open a bit, then you will use more fuel because your engine will be running too cold. Faulty temp sensor can also cause this.
 

Clovance

New Member
Joined
Nov 9, 2012
Messages
120
Reaction score
0
Points
0
Location
Townsville
Members Ride
VT Executive S2, built 1999, 3.8l V6
Hey guys,

Thanks so far.

Tyre pressure ok. Nothing overfilled, all good. Back 38psi front 34 psi. Loaded means about 200-300kg plus me all the time. And pls spare me your suggestion to put less in the car. I need all that stuff so it is not a solution.

I get my figures from calculating:
Write down the odo. Fill up until it clicks and stop then. About 65 liters are in the tank now.
Drive (in my case only city)
Refill until it clocks and write down the odo and how much liters you put inside.

The difference between new odo and old odo divided with that number to get 100km. Divide the same number to the amount to just refilled.

I did that at least three times and now the average is about 20l/100km.

There is no more precice way to calculate your fuel consumption.

What is EGR and TCC and how can i check them?

How can i check if my thermostat sensor is faulty or not?

Yes normally the engine warms up properly.
 

Munz

Right Foot Action
Joined
Jan 23, 2011
Messages
2,276
Reaction score
5
Points
38
Location
Brisbane NTH
Members Ride
VZ Calais LS1 / VL RB30e daily
Whats your average speed?

edit: didn't read the part where you write stuff, thought you were getting numbers off the dash.........my bad
 
Last edited:

lout

Well-Known Member
Joined
May 13, 2006
Messages
3,411
Reaction score
912
Points
113
Age
58
Location
Langwarrin Victoria
Members Ride
VX Executive Sii
were they quality O2 sensors or the cheapest you could find on Ebay?
are you using quality fuel or E85?
are you using Ac most of the time up north?
drop your rear tyre pressure, that is a bit high, 34 all around is more than enough
what sort of condition is the engine in? does it use much oil?
and we have learnt our lesson, is the engine stock?
 

Jonah 101

Undefined
Joined
Jan 15, 2012
Messages
1,413
Reaction score
16
Points
38
Location
Rotorua
Members Ride
R32 Skyline
I think you could have a blocked exhaust. Anything else I think you would notice a serious issue with you car.
 

Clovance

New Member
Joined
Nov 9, 2012
Messages
120
Reaction score
0
Points
0
Location
Townsville
Members Ride
VT Executive S2, built 1999, 3.8l V6
Hey guys,

I just drive city speed - and i am in adelaide right now, so most of the times 50-60km/h and i use my AC here not at all.

The oxygen sensors are Bosch genuine ones for 95$ each. I researched th correct part number and got the right ones.

Normally i use e95, sometimes e91.

The tyre pressure was too low with 36, because ive got so much stuff loaded it looked flat with 36, so i put it a bit higher. Should be fine...

The car is in very good condition in my eyes. Doesnt need very much oil and engine sounds fine in my eyes.
What do you mean with "engine stock"?

Lol blocke exhaust? Ok - maybe but how can i know? :D
 
Top