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VS fuel economy problems

kbn000

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Hi All
My VSII wagon (Lexcen - Boo hiss i hear you say - but it is still technically a commodore!!) is experiencing bad economy - i am getting around 400km to a 63 litre tank :b: - i used to get around 550 to 600 :w00t: .
i have changed filters, leads, plugs, thermostat.

next on the list was an injector clean. i rang one place and they have told me for commodores they recommend an 'on board' cleaning, where for $185 they put through a special cleaning agent under pressure which supposedly does the job. has anyone else heard of, or done this :confused: ?

i was assuming the best bet would be to remove them, but they said no, as their method cleans the lines and everything going to the injectors as well.

Also, my on board computer when checked for errors showed there were no problems. is this a guarantee that the 02 sensors are okay? or can they fail and not be picked up by the computer?

any help would be appreciated. thanks all. :thumbsup:

One more thing - i don't want to show my stupidity, but in reading other threads trying to find an answer i have the following Q's: What is a CAI? & what is an IAC valve?
 
V

VSAccCom

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Mkk get em done outa car for like 220-250 bucks and a Cold Air Intake = CAI and Idle Air Control = IAC
 

hako

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That figure you quote of 550 to 600 km out of 63 litres sounds a bit extreme if you don't mind me saying so....I'd be happy to get 450 to 500km out of a tank so I wouldn't be too worried about 400km as it may just be due to changed driving habits like city versus country driving or using the airconditioning etc. A can of injector cleaner will sometimes work and is a lot cheaper. Watch out you don't spend more on improving your economy as it may take years to recoup what you spend trying to improve it....bit like a dog chasing its tail.
 

dlzn

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im getting around 360 without reserve kicking in.
i drive half/half...

just got few more mods.. havnt been paying to much attention to economy latley, guess its better.
 

Raging Bull

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I used to get 360 every week pretty much, then had injectors ulstrasonically cleaned, thermostat and coolant sensor changed and I now get over 400 all the time.
 

pj

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Oxygen sensers are the most likely cause of poor fuel consumption, I think you'd be wasting your money getting the injectors cleaned, they would be the last thing i'd be looking at.
 
M

Masher

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Check:

tyre pressures, wheel alignment, ??brakes binding????...basic stuff, but I agree with Hako...takes a heap of motoring to recoup the money you can spend trying to get the economy "back up"....I only used to get about 400 out of my VP wagon.....also, I reckon could be sh@@tty fuel as well. if it's running OK, I wouldn't worry too much about it...you're keeping one more Sheik in Ferraris :)
 
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foxinjox

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poor fuel economy

i thought 9 lt /100km was not so good...highway driving..reading this its seems ok.

i suggest to check for vacuum leaks...injector cleaner....
...fuel pressure...i would also like to know what the deal with oxy sensors are..if there is no engine light can they still be stuffed or worn

FIJ ;)
 

kbn000

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Thanks people, the advice is appreciated. does any one know if the O2 sensors can go and not show up on the computer though? i don't really want to spend the $$ on the sensors just to find the old ones were okay :cry: . Also, do you have to go genuine, or are there just as good a quality after market o2 sensors?
 
M

Masher

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Again, if it's running well, particularly when it's hot (starts OK when hot?), and no black exhaust smoke, I'd assume the 02 sensor is OK...it's like the old saying...don't mess with it if it's not broken, or it soon might be!:)
 
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