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Thread: VY Commodore Wagon pig to start when fuel 1/4 full or below. Any ideas?

  1. #1
    Lionelgee is offline YarnMaster Silver Subscriber
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    VY Commodore Wagon pig to start when fuel 1/4 full or below. Any ideas?

    Hello All,

    No - not get a different car.

    With 256 000 klms on the clock my trusty daily driver has developed an interesting quirk. When the fuel level drops to a 1/4 or below it becomes a right pig to start. Courtesy of my mechanic, I have been running a fuel pressure gauge over the past week. The first purge has the pressure going up to 50 psi. Then it runs at the 45 psi mark. Normally the car starts on the first turn of the ignition - never any need to touch the accelerator. Now, after the car has sat for a couple of days with 1/4 tank of fuel it requires multiple attempts to start. These attempts to start need to be accompanied by having to pump the accelerator. In this situation after the initial purge at 50 psi the pressure goes down to about 35 psi. Once the engine has started and runs the fuel pressure is maintained at 45 psi.

    Today, I could tell that there was drain on the battery before my repeated cranks got the engine to run. It is almost like the fuel is draining back from the engine and returning to the tank. This need for multiple cranks to start the car is totally out of character for it. I have had the car since 2015 so I know its 'normal' behaviour.

    Yes, I could just make sure that the fuel levels do not go below 1/4. However, will the problem increase until the required fuel level becomes not below 1/2 a tank, to it becoming 3/4 of a tank of fuel? Something is amiss and it will not get better by itself.

    So where to from here?

    Kind regards
    Lionel

  2. #2
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    fuel pump or fuel filter issue
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  3. #3
    BradC is online now Super Moderator
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    Common symptom of an in-tank pump failure on many vehicles. I see the VY has an in-tank pump, so I'd start there.

  4. #4
    Lionelgee is offline YarnMaster Silver Subscriber
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    Quote Originally Posted by trout1105 View Post
    fuel pump or fuel filter issue
    Hello Trout and Brad,

    I initially ruled out a fuel filter issue because once the engine is running it is faultless and smooth. What stopped me from immediately getting a replacement fuel pump was how it maintains its pressure - when running properly - within the correct parameters for the pump. Except when the fuel gets below a 1/4 and it does not seem to get the fuel it needs to start and run - go figure!

    Of course it involves dropping the fuel tank to be able to change the fuel pump. Then while I am at it I will replace the fuel filter.

    Kind regards
    Lionel

  5. #5
    Lionelgee is offline YarnMaster Silver Subscriber
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    Hello All,

    I ordered a new fuel pump today. I might as well start with the most likely fault first. Of course it is also the dearest part. If that does not sort the issue out the second dearest part is the fuel pressure regulator. Hopefully the first part will be the fix. Luckily for me there is a step-by-step clip on YouTube which also recommends from experience which brand of fuel pump not to buy. The poor bloke had to drop his fuel tank three times before it was sorted! Fingers crossed that I will only have to drop the tank once.

    Now I just have to get the car started so I can take it to the fuel station and get the fuel level above a 1/4 while I wait for the postie to drop off the new fuel pump. I will let you know how I go.

    Kind regards
    Lionel

  6. #6
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    Quote Originally Posted by Lionelgee View Post
    .....

    Now I just have to get the car started so I can take it to the fuel station and get the fuel level above a 1/4 while I wait for the postie to drop off the new fuel pump. I will let you know how I go.

    Kind regards
    Lionel
    I would have thought it better not too do this!
    Two reasons.
    1/. less fuel in tank = to less NEED to drain it to drop it. less weight in tank = easier to lower it, and if drainage is NEEDED, then you have less in tank to drain(and store).

    2/. also, as your issue is that below 1/4 full it's hard to start, I'd have thought that to see if the issue is resolved, keep it at 1/4 or less do the pump, did it fix the issue.
    Arthur.

    '99 D1 300Tdi Auto
    '03 D2 Td5 Auto

  7. #7
    Lionelgee is offline YarnMaster Silver Subscriber
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    Quote Originally Posted by AK83 View Post
    I would have thought it better not too do this!
    Two reasons.
    1/. less fuel in tank = to less NEED to drain it to drop it. less weight in tank = easier to lower it, and if drainage is NEEDED, then you have less in tank to drain(and store).

    2/. also, as your issue is that below 1/4 full it's hard to start, I'd have thought that to see if the issue is resolved, keep it at 1/4 or less do the pump, did it fix the issue.
    Hello Arthur,

    Yes, more fuel equals more weight. I am fully aware of that.

    I also know being able to start the car with just one turn of the key and not having to almost drain the battery before the engine fires into life is worth the extra weight. By the time the postie drops the new fuel pump off the tank will be close to a 1/4 anyway. In the meantime I have trouble free motoring and hell of a lot less angst every time I go to start the car.

    Kind regards
    Lionel

  8. #8
    Lionelgee is offline YarnMaster Silver Subscriber
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    Hello All,

    I just received a message from the supplier....

    Your item is being organised from one of our interstate storage warehouses to our local dispatch centre, which has resulted in a 3-4 business day delay on your order.

    Sigh! More waiting. Anyway, I should have even less trouble with getting the fuel tank back down to a 1/4.

    Kind regards
    Lionel

  9. #9
    Lionelgee is offline YarnMaster Silver Subscriber
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    Hello All,

    You know how I wrote about how the lack of fuel delivery to the motor may become progressively worse and have the issue go from below 1/4 of a tank to a higher fuel level? The tank is at 3/4 and now the sod has the same fuel-starved problems. Just as well we are a two car family. I could not be bothered trying to get the thing started today - stuff it! Oh yes, I did utter some more somewhat colourful words just a little while ago!

    Kind regards
    Lionel

  10. #10
    Lionelgee is offline YarnMaster Silver Subscriber
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    Hello All,

    The Commodore is up on a set of ramps under the back wheels. The tank is out and away from the vehicle and the new pump installed. I bought the special fuel line disassembly tool used on GM products. The two outside lines came out okay. The centre pipe - the one hooked between the fuel pump and the fuel filter actually broke the special disassembly tool. I exchanged the purchased this morning and broken by lunchtime special tool and attempted to get the middle line off again with the replacement tool. After many fruitless attempts I decided to follow an alternative path of reason. The new fuel pump is a completely new unit where everything is totally replaced. The old pump was destined for the recycling wheelie bin anyway. The only thing stopping me from being able to remove the tank - fit the new fuel pump - then reassemble everything was a pipe on a soon to replaced pump. A part whose value was zip. Bend the pipe a bit - bend a bit more "Snap".

    It turns out that out of the three pipes coming out of the fuel pump the middle one was very deteriorated compared to the others and it has fused into place within the joint. The special disassembly tool was accordingly rendered useless. It was also quite fun to get the broken pipe out of the special quick - scoff - scoff - fuel line snap fitting. Those fittings might be great early in a car's life. However add 18 years of operation and things are quite that supple and quick to release any more.

    Tomorrow's task is reassembly and refitting the tank. Wish me luck. Gee I hope the fuel starvation issue when the fuel level in the tank reaches 1/4 and below no longer happens after this endeavour!

    Kind regards
    Lionel

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