John C
Member Since: 28 Aug 2007
Location: East Yorkshire
Posts: 3292
  
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| Fuel Line - Non Return Valve? |
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Hi,
Have a weird thing... If I leave the car for a few hours (8 or so) it the car takes longer to start (2-3 seconds cranking before it fires up). It's definitley not the battery. If I then immediately turn off the car, and then try and start it again, it starts instantly.
Almost like there's fuel that's drained away over time and is being pumped back to the engine.
Is there some sort of non-return valve that could be inefficient?
Thank you!
John 2020 SDV6 D5 HSE, Carpathian Grey +
2022 Tesla Model Y LR... almost Carpathian Grey
Previously : 2005 TDV6 SE Auto, Cairns Blue (288K) - ours for 16 years
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 10th Oct 2017 8:08 pm |
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Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
 
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The fuel pump runs when the ignition is on so providing your are waiting for the glow plug lite to go out, shouldnt be an issue
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| 10th Oct 2017 8:25 pm |
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hugeviking
Member Since: 08 Jun 2010
Location: cotswolds
Posts: 1482
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I have same and am interested in an answer
So bump 
Andi.
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| 11th Oct 2017 2:42 pm |
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BrettKaz
Member Since: 11 Nov 2013
Location: Canberra
Posts: 209
 
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When the car takes longer to start is there quite a lot of white smoke out the back. This means fuel is being pumped just not combusting properly (glow plugs/injectors). No white smoke would indicate fuel not there.... which is a bit odd.
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| 11th Oct 2017 3:39 pm |
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John C
Member Since: 28 Aug 2007
Location: East Yorkshire
Posts: 3292
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Thanks for the reply - no smoke! 2020 SDV6 D5 HSE, Carpathian Grey +
2022 Tesla Model Y LR... almost Carpathian Grey
Previously : 2005 TDV6 SE Auto, Cairns Blue (288K) - ours for 16 years
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| 11th Oct 2017 3:54 pm |
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BrettKaz
Member Since: 11 Nov 2013
Location: Canberra
Posts: 209
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I would be looking at injector leak off ... also search on this forum. One of the comments on here was that an Audi maintains 10psi as backpressure in the leak off system to 'assist starting' ... he doesn't conclude if LR maintains backpressure.
http://w.uniteddiesel.co.uk/faq/what-is-an...-back-test
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| 11th Oct 2017 4:32 pm |
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BrettKaz
Member Since: 11 Nov 2013
Location: Canberra
Posts: 209
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I came by this while searching one of my own problems... may help you however @robbie who is a bit of a whizz seems to think the High Pressure Fuel Pump should reach pressure quick enough not to cause start problems via leak off. If your issue is the HPFP then you may start to get some of the symptoms to the extent noted in this post.
I would still have a look at the injector offset values and while I'm not sure there is any correlation b/w excessive leak off and poor injector performance if you need a new injector or 2 then you should get that done anyway and hope it fixes both issues. Your wallet will want you to make darn sure of an issue before you replace the HPFP. Definitely wouldn't replace based on symptoms noted in your post ... if the only thing you're concerned about is 2-3 second delay on cold start then you are a heck of a lot better off than me... definitely in the wait and see category.
While 'waiting and seeing' you might search the 2 stroke oil thread. Apparently 2SO lubricates the HPFP so you might try that to extent the life of the pump. 2SO is either miracle juice or  depending on what your mood is when you read it. Some of the trusted pros on here use it ... the others don't like marmite.
https://disco3.co.uk/forum/topic129790.html?highlight=Surging
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| 12th Oct 2017 3:24 am |
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