ID/DS minimum fuel in tank to run?
  • Register
  • Help
Results 1 to 8 of 8
  1. #1
    Fellow Frogger!
    Join Date
    Nov 2010
    Location
    canberra
    Posts
    289

    Default ID/DS minimum fuel in tank to run?

    So I finally got around to putting fuel in my reburbed fuel tank.

    I put about 14 litres in, only to find that a) the tank's pick up pipe was still drawing only air... and b) when i "drained" the tank via the intank filter plug, only about 3 litres came out.

    So i ensured the plastic insert tube was flush with the bottom of the in-tank fuel filter, refilled with the 3 litres that came out..

    Still no suction

    It wasn't until i had put about 18 litres in the tank that fuel pressure was achieved..and she ran from her own fuel tank for the first time in 30 years.

    There is, in my situation a patently obvious reason that this may be occurring, in as much as I lost about the top 3cm of the plastic insert tube, and this is probably causing an air leak unless there is sufficient fuel to take the level above the metal fuel pick up tube.

    BUT...Question Is the minor air leak created by the gap between the outer metal tube and inner plastic tube differentially enough to prevent suction and fuel pressure

    ORRRR...Does the D actually in standard setup need more than 18 in the tank to keep running..

    Advertisement


    I ask this (as said) with 14 litres in the tank only 3 litres came out, and I'm wondering whether my "modification" has little to do with the D's minimum perceived fuel requirement, or perhaps just adding to an already identified issue with lower fuel level in the tank

    Ultimately i will get a new insert, or at least a piece long enough to extend out from the tanks outlet pipe to attach to the existing plastic line along the sills to the fuel pump..

    Regardless of above....

    Happy days with with largely self contained fuel source, fresh spheres, wiring heading the right direction and funky new interior ready to go in..

    thanks in advance for any input..

  2. #2
    Fellow Frogger! badabec's Avatar
    Join Date
    Feb 2012
    Location
    Ongar / England
    Posts
    832

    Default

    After I drained the tank and cleaned the stack of washers filter, mine needed only 1 litre to get up and running. I put in 5 litres and bent the fuel gauge arm in the dashboard to empty (so I know i have 5l reserve).
    Where has the petrol gone? If it went in, and the car is level, it must come out.
    There are plenty of threads on here about the fuel pick up pipe and the problems caused.

    DS fuel tank
    Last edited by badabec; 19th December 2018 at 07:03 AM.

  3. #3
    1000+ Posts dogboy's Avatar
    Join Date
    Sep 2001
    Location
    melbourne,victoria,australia
    Posts
    1,332

    Default

    is the car on flat,level ground? if not then that may be your problem
    Rev. Dogboy


    1969 DS21 Pallas BVH with leather
    1970 Renault 16TS
    1967 Honda S800 cabrio
    Citroen 1970 DS21 Cabrio replica
    Citroen 1966 ID Safari (with 23 running gear)
    Citroen 1975 DS23 Safari
    1975 VW Kombi poptop
    1987 2CV
    Porsche Boxster S manual
    1988 Vespa PX200E

  4. #4
    Fellow Frogger
    Join Date
    Jan 2004
    Location
    Sydney
    Posts
    9,777

    Default

    There is something odd about adding 14 litres to a dry tank and then draining off only 3? That's over 2 gallons 'missing'. It presumably hasn't leaked as you would notice 2+ gallons of leaked fuel. Did you drain it by pulling out the little plug in the middle of the filter plug?

    The pickup filter with the plates (not on EFI) is inside a baffle box to stop fuel surging around corners. Did the tank refurb include adding goop to the inside of the tank? If so, what steps did you take to stop the goop blocking the internal filter and passages intended to let fuel into the baffle box? Did you remove and clean the discs making up the filter? The middle part of it is quite fragile.

    The pickup tube should be right at the bottom of the tank and it needs to make a good seal with the rubber hose on the inlet. Otherwise, air may be drawn around the plastic tube instead of drawing fuel from the bottom of the tank.

  5. #5
    Fellow Frogger! Don B. Cilly's Avatar
    Join Date
    Dec 2014
    Location
    Mallorca, Spain
    Posts
    435

    Default

    Something similar happened to me.
    I drained the tank - from the suction filter hole - took it off, and there were still over ten litres of petrol in it.
    I think it was because the "partitions" in the tank were clogged with rust, so the remaining petrol stayed at the sides.

    Now, your tank being "reburbed"... it depends on how you "reburbed" it.
    If you cut it open and thoroughly cleaned it, that is unlikely.
    It could be that you should have drained it via the small screw instead - although a 12-litre difference is not likely either.

    If you just cleaned it by, say, filling it with screws and shaking it, then added some sort of epoxy "repairer", you may have permanently sealed the gap between the partitions and the bottom of the tank. So any fuel on the sides of those, and below their level, will just sit there - at least until the next sharp turn
    .

    About the air gap... the nylon (rilsan) tube should be an unbroken line from the bottom of the filter to just before the fuel pump.
    So it shouldn't suck any air if the outlet metal tube is not properly sealed. It will definitely smell though.

    [EDIT] Ah, the end of the nylon tube that goes into the filter should obviously be cut at a 45ļ angle, or it will clog really easily ;∑)

  6. #6
    Fellow Frogger!
    Join Date
    Nov 2010
    Location
    canberra
    Posts
    289

    Default

    Thanks for input everyone

    The "refurb" was tank dipped in acid bath.. then repainted so no volume loss nor any blockages from goop..
    The rilsan pipe was unaffected by this bath. (Surprisingly)

    The car is currently on a dead flat surface..
    The lowest point of the rilsan suction tube is 45degree cut; But as stated is not a continuous length as when I removed the tank I inadvertently mangled the top 3cm that lead into the tank pick up pipe..so i cut it and put a fuel hose stent between the "sill bound" rilsan and the tank's fuel outlet nozzle.

    I can definitely see how this MAY be a problem once fuel level drops below the metal fuel pick up pipe that guides the flexy rilsan, but I was hoping pressure could still be achieved down to the relative rilsan hose diametre vs the small potential air ingress from the gap..

    Still doesn't explain the paltry 3 litre drain!!

    Anyway I'll read further the link provided and see what I can glean.

  7. #7
    Fellow Frogger!
    Join Date
    Nov 2010
    Location
    canberra
    Posts
    289

    Default

    Hoping that now that the pick up is primed that the any minor air leak transgression will be negated..

  8. #8
    Fellow Frogger! badabec's Avatar
    Join Date
    Feb 2012
    Location
    Ongar / England
    Posts
    832

    Default

    Hello, have you pulled the rilsan pipe out of its metal guide tube to make sure it is completely intact?

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •