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very bad fuel economy

Discussion in 'VT - VX Holden Commodore (1997 - 2002)' started by moocow, Oct 31, 2012.

  1. frogsta

    frogsta Sleeper

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    Lol my bad I guess IAC may be worth replacing at $30 anyway as well as TPS
     
  2. CommieKal

    CommieKal New Member

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  3. umair

    umair New Member

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    Ok when was the last time you changed your fuel filter? If it was not changed yearly or two then your fuel system is plugged. That cause the injectors to stuff and destroys the catylic converter. Your car will probably not shoot at WOT, there will be delay. You will have to drain the fuel tank and flush it, then change the fuel filter and clean the injectors by a injector cleaning kit, then replace the catylic convertor. If you run the injector cleaner bottle (the one you add in the tank) put two of them together in an empty tank and then fill up. My car had the same problem and it destroyed the catylic convertor. I put fuel injector cleaner (gm ac delco) in it and changed the fuel filter and now the power is back and its giving double fuel economy. Now I just need to change the catylic convertor.

    Please not if the fuel filter has been changed yearly or per two years, then the problem lies somewhere else.
     
  4. inasinman

    inasinman inasinman

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    I'm very interested to find out the solution for this problem too. It's giving me the s**ts.

    changed:

    new 02 sensors
    new injectors
    new plugs
    new leads
    air filter
    fuel filter
    temperature sensor
    temperature sender
    cleaned MAF
    cleaned throttle body
    new thermostat

    recently done the head gasket and inlet manifold gasket.

    still doing bloody 300 Km per tank.:bang:
     
  5. frogsta

    frogsta Sleeper

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    Check vacuum leaks, replace tps, error codes
     
  6. lout

    lout Well-Known Member

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    inasinman, i see you haven't changed your TPS yet
     
  7. moocow

    moocow moo_c0w

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    sorry for the late reply.
    found out I had a broken exhaust manifold stud. Just got it replaced and it seems to have fixed it. Fitting extractors soon which will hopefully prevent it happening again XD
     
  8. Woody_SS

    Woody_SS Defective User

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    Yearly or 2... really for $20 - $30 mine gets changed every time I give a service (10,000kms ish). Couldn't imagine leaving it on the car for that long
     
  9. s_ikari2015

    s_ikari2015 Fun IS easier with an 8

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    Idle Air Control valve is also easy to clean, and cheap to replace if you break it. DEFINITELY worth checking at every service and still worth checking now that the exhaust leak has fixed the problem.

    Two screws, a plug... then a clean cloth and some WD40.
     

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  10. frogsta

    frogsta Sleeper

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    I just replaced my IAC with the TPS, thought may as well as I got both for $30 each no harm in that really. TPS fixed hesitant take off and helped with my fuel economy, IAC helped my idle, sits at 650ish now instead of 750-800
     
  11. hho

    hho New Member

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    I've had similar problems in the past. I installed a hydrogen generator (less than $400) and reset my o2 sensors to accept the extra air. I immediately noticed a vast increase in response and power, the fuel consumption changed from 6 kms liter to 9 kms liter and much higher on the highway. I am going to put spark plug anti foulers on the 1st o2 sensor (before the cat) which should lean my mixture even more, I will then up the amps of the hydrogen generator to produce more hydrogen to replace the less petrol. I am hoping to run on 75% hydrogen and 25% petrol - this should give me a huge increase in fuel economy. I have run my car (96 VS ecotech) on just the hydrogen a couple of times but found that the gas volumes were no enough to run the engine for more than 3 minutes. I am aiming to try and up the gas from my unit so that cut out the petrol completely, then I'll just need water to run my car! Worth a try as costs very little to find out. You might to reset the sensors as they might be on the old reading. To do this just disconnect the negative lead 1st then the positive, 30 mintues later turn the key to the on position, and 30 minutes later again, stand on the brake pedal for 5 to 6 seconds, turn off take the key out, then connect the neg lead then the positive lead. Now you need to go for a 20 minute highway run (best) to reset the sensors to the new settings. This may help.
     

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