Discussion in 'General Motoring' started by Chris, May 30, 2007.

  1. Chris

    Chris Guest

    Hi All,

    I've just has my astra converted to run on lpg - well 1000 miles ago. It
    works well, and has a 'flashlube' system fitted which lubricates the valves
    as LPG is a dry fuel compared to petrol.

    I was just wondering, does any1 have a factory fitted vauxhall lpg system,
    and does it have a similar flashlube system fitted?

    Chris, May 30, 2007
  2. Chris

    Ian Hatten Guest

    Hi Chris

    I have a factory fitted LPG system fitted to my 2005 Corsa 1.2. I have had
    it since new and it does not have any flashlube system. It will be 2 years
    old in a couple of weeks and has covered 48,000 miles with, touch wood, no
    problems at all with the engine running. Filling the tank is a different
    kettle of fish though and very inconsistent.

    Ian Hatten, Jun 1, 2007
  3. Chris

    Chris Guest

    Hi Ian,

    I was a little surprised when I found out that the flashlube system had been
    fitted - as I thought that if the engine was designed to run on unleaded
    fuel, then the valve seats were hardened and so would run no problem on

    Mind you the engine is the 1.6 8v variety, so perhaps, as this is an old
    design, then the flash lube is in fact needed.

    I've only filled up on LPG about 3 times so far - it was fairly
    straighforward once someone told me how to do it.

    What problems have you been having?

    Chris, Jun 2, 2007
  4. Chris

    Ian Hatten Guest

    Hi Chris

    I have a 48 litre doughnut tank in the spare wheel well. Taking the general
    rule that you should only ever be able to fill it to 80% capacity that
    should mean I would get a maximum of 38 litres when empty. The majority of
    times when I have filled it when the car has actually run out of gas I have
    only been able to get 33 litres of gas in before the pump shuts off
    suddenly, but on one occasion I have managed to get 48 litres. Other times
    when I still have had gas in the tank I have managed to get up to 45 litres
    in. I have noticed when I do not get as much gas in the tank as I would
    have expected the pump has shut off suddenly, other times when I get more in
    it will slow down near the end. Lowest range I have had to a tank is 255
    miles with the highest being 368 and it is practically all the same type of
    driving, 80% motorway, using cruise control, and 20% A roads, so even trying
    to use the range for filling up seems inaccurate for me. Car is still under
    warranty but the nearest authorised LPG dealer for me will be 50 mile trip,
    probably once for a diagnosis then another trip to get fixed if anything
    needs doing. Overall I am averaging 38mpg on LPG and just got my tax disc
    in at £15 for the year so definitely worth me continuing with LPG.

    Ian Hatten, Jun 2, 2007
  5. Chris

    Mike Guest

    You will find that you get the most consistent fills if you use the same
    pump. However the only way to get a good
    idea of what you are getting to the gallon is to record all your fills and
    mileages for a couple of months, then work out the average over that period.

    when the pump shuts off suddenly thats the valve in the fuel tank shutting
    off the inward flow of gas at around the 80% mark. But it can be a bit
    variable, i.e. not too exact. If you let the gas run out then the float
    valve that controls this (think of a ballcock in a toilet cistern) tends to
    stick sometimes at the bottom of the tank, so no controlled cutoff. The
    refuelling pumps are controlled by back pressure. If the valve suddenly
    shuts at the right level then the pump suddenly shuts off, but if it has
    stuck open then the pump will fight a slowly loosing battle against the
    remaing space in the tank being compressed until it reaches its own pre-set
    cutoff pressure.

    But dont worry too much about it especially with an internally mounted tank
    that isnt subject to corrosion (if mounted under the car exposed to the
    elements) as the tanks have massive safety margins. They also have emergency
    pressure relief valves as well, so all it would cost you is some money in
    wasted fuel.


    ex- 3.5l 86' range rover manual 21mpg on lpg
    currently (laid up) 4.0 95' cherokee auto 17 mpg on lpg
    Mike, Jun 3, 2007
  6. Chris

    Ian Hatten Guest

    Thanks for that Mike.
    The average I have worked out is over the entire length of time I have owned
    the car. I keep a record of this as it can give an insight into problems
    that may be arising.
    Out of 184 fill ups only 24 have not been from my usual pump, mainly because
    it is up to 12p a litre cheaper than other places I can use.
    The float valve could well explain another thing too. It has not happened
    for a while now but sometimes after filling with gas the fuel gauge would
    take a good 15 to 20 minutes to register back to full. It was one of these
    things I was to pop back to the garage with when it happened to let them see
    Ian Hatten, Jun 3, 2007
  7. Chris

    Mike Guest

    If you have to pay for the float valve being fixed then dont bother-its more
    trouble than its worth. If you do have it done then run the car out of lpg
    before it goes in, as they have to depressurise and open the tank to get at
    things. Going in with a full tank of gas is just wasting a full tank of gas.
    But the float-as you have deduced-also works the fuel guage. Some tanks also
    have an analog guage on the tank itself and if you can see this while
    filling it will tell you if the valve is stuck, as the needle will not move.
    Usually hitting a bit of a bump is enough to dislodge it.

    Mike, Jun 3, 2007
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