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Fuel issue on steep decline driveway?

Discussion in 'VF Holden Commodore (2013 - 2017)' started by snortings, Nov 22, 2018.

  1. snortings

    snortings Active Member

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    Hi,

    I recently bought a 2015 VFII SV6 Sedan, and have noticed an issue when it tries to start. Our driveway at home is on a fairly steep decline as our house is lower than road level. I’ve noticed when the fuel level gets near halfway it has trouble starting. It just cranks and cranks but it’s like it just isn’t getting any fuel. It eventually springs to life after long cranking.

    Is there a known issue for this? When I filled up the car for the first time when it first happened it stopped, but now that it is back near halfway the problem has returned. I don’t want to run it below halfway and potentially get stuck on the driveway because it isn’t receiving any fuel to the engine... How is the fuel pump designed etc? It’s definitely not the battery. Is there a design flaw or something?

    If you need any more info let me know
    Thanks
     
    Last edited: Jan 4, 2019
  2. snortings

    snortings Active Member

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    Just thought I’d add, this issue has never happened on level ground, only on the driveway. It shakes a little bit until I get off the driveway, once it’s off the decline it runs fine. Though idiling on the driveway is fine when I return from the road.
     
  3. HarryHoudini

    HarryHoudini Active Member

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    The usual go is to back the car down the slope and see if the problem is still there,if it is then its not the fuel pickup/pump sucking air.
     
  4. Smashfist

    Smashfist Active Member

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    Does it do it every time? A good way to test is to cycle the ignition a few times before starting - key on, key off, key on, key off, key on, delay a few seconds between each, then start it. This cycles the in tank fuel pump to prime the rest of the fuel system.

    It sounds like a possible anti-drain back valve allowing the fuel system to bleed its pressure back into the tank which means it has to prime the whole car's worth of lines before feeding the engine. The above will allow you to test that theory (if it stops faulting it's 99% a fuel pump).
     
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  5. wetwork65

    wetwork65 A wet business

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    Could it be the Fuel filter? If blocked it will take some time to presurise the system, especially if pushing against gravity.
     
  6. Smashfist

    Smashfist Active Member

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    They don't have fuel filters, only an in-tank strainer. Unlikely to be fouled (as a strainer, normally it's just to stop picking crap up, when the pump is turned off the bits fall off the strainer back to the bottom of the tank).
     
  7. snortings

    snortings Active Member

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    Thanks Harry, I've tried reversing down the driveway now and so far it hasn't happened.

    Hm, I'll try this after I see the outcome of reversing on the driveway.

    ------------------------
    Got a video of it happening, might provide some more insight. This was with the car pointing down the driveway. As you can see, it eventually kicks in.

     
  8. figjam

    figjam Donating Member

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    Ford Territorys have a reputation of being hard to start with less than a half tank of fuel when parked a certain way on an incline. The fuel pump can't pick up the fuel. But no problems when they are level. Perhaps your problem is the same ?
     
  9. HarryHoudini

    HarryHoudini Active Member

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    I have a VN wagon and if you get down to around a quarter tank or less you can't park it on a severe left hand slope,just won't start,pickup must be in the RHS of the tank.
     
  10. Murdoch

    Murdoch Active Member

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    you sir have a great Australian made vehicle
    I VN wagon has more street cred than any other holden built post 1989
     
  11. wetwork65

    wetwork65 A wet business

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    Yep - big job to take out and and clean/replace, so not the first item to try. The VF workshop manual describes the strainer and filter but lacks detail on how to replace. Monstar did a great writeup earlier this year, when he was around the forum.... I do miss his input. https://forums.justcommodores.com.a...s-on-vf-6-0-calais-sedan.270207/#post-2955568
     
  12. tml678

    tml678 Well-Known Member

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    What happened to him? I read that he was banned (again) but there’s nothing on his profile indicating that.?
     
  13. Skylarking

    Skylarking Well-Known Member

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    Yep, @monstar always added a strong technical spin to threads but for some reason, his posts sometimes seemed to get up some people’s noses and the thread would regress into a shite storm.

    I particularly liked Monstar's take on solving the VF fuel tank access issue though I’ve yet to apply such a fix to my VF (maybe when the pump inveriably fails). It's a pity the jc links seem dead.

    As for OP’s incline start issue, of possible related interest may be this VE thread. Monstar indicated in this post that having tank at least half filled was one way to avoid pump failure due to overheating (which seems that main culprit according to him). @RiCeY also made a post within about charing of pump connectors and replacing the fuel pump harness along with new pump.

    One particular post of interest was Monstars statement about fuel pressure being 200Kpa or less along with tell-tale cutouts on left hand turns and inclines being an indicator of pump failure to come. OK, the thread was w.r.t. VE but who knows, maybe its a common VF issue as both share zera platform and especially so if VF has same pump as VE (but i don't know). In any case, that VE thread is linked for those interested in going down the 3 page rabbit hole.
     
  14. wetwork65

    wetwork65 A wet business

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    Gone since some time in July for some reason.
     
  15. HarryHoudini

    HarryHoudini Active Member

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    I read online a few years back,(Whirlpool ?) that GMH added a 2nd pump to the back of the V6 Engine from VE Series 11 forward.
    I can't see it mentioned in the manual i have for a 2012 3L but someone on here may know if that is true or not.
     
  16. lmoengnr

    lmoengnr Well-Known Member

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    Its the high pressure pump for the Direct Injection.
     
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  17. snortings

    snortings Active Member

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    Thanks, just had a read. Whilst keeping the tank above half full would seem to resolve the issue (in my case at least), it's something that I really don't think I should have to do. Interesting thread though... wonder how I'll explain the issue to the dealership when it goes in for a service, will be very hard for them to replicate cause it's not very frequent. After it does have its moment, it starts up fine after.

    Right now it's sitting at about 1/4 of a tank, and so far reversing down the driveway hasn't proposed any issues. Must be the fuel pump...

    See now that it's at 1/4 of a tank, I don't want to try this incase I get stuck on the driveway... it's a very steep slope and if anything happened the car would go rocketing forward into the garage and smash into the house.

    -----------
    @RiCeY Sorry to call on you to this, but any insight into this issue :p? How should I explain this when I go in for a service? All I've really got is a video to show what happens, very hard to replicate as it won't do it every time. How much you think the pump would cost if it is?
     
  18. HSVBMW

    HSVBMW Member

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    Within a fuel tank is a saucepan sized container called a swirl pot. Your fuel pump sits inside of it and fuel is drawn from the base of pump ,sent to injectors and the left over is returned to the swirl pot via the return line. This keeps pot full to brim at all times regardless of fuel level in tank. It is common in older commodores for the return line to fall off swirl pot connection to pot causing returned fuel to go straight into tank not pot. This leaves pot at actual tank level not full to brim. This means acceleration, cornering,steep angles causes fuel to move away from pump pick up and suck air or cause pump to overheat as pump must be submerged to stay cool. Above half a tank is above top of fuel pot and stops issue happening as pot is then full. This is 98% of the time the issue,keep tank half full until repaired and no issues should continue. Monster was great because ha actually knew what he was talking about.
     
  19. Skylarking

    Skylarking Well-Known Member

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    I understood the VF's used a PWM fuel pump which controlls fuel presure and fuel volume, hense no need for a return line from the injector rail to the tank. If so, there can't be a swirl pot in a VF tank as there would be no return line to fill it o_O

    Happy to be corrected if i've missunderstood it ;)
     
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  20. wetwork65

    wetwork65 A wet business

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    The manual states that there is no return line and runs on demand. So you are probably right.:)
     

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