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Thread: Can anything else look like a fuel surge problem?

  1. #1

    Thumbs down Can anything else look like a fuel surge problem?

    I believe I have a fuel surge problem in my 69E historic race car (2.1 litre mfi motor).

    The car has a plastic RS style tank and even with 60 litres of fuel on board it has power losses coming out of turn/braking zones. All the gauges stay on, tach drops a bit, loses power, then a second or two later all is well again. Almost feels like a giant flat spot.

    I've just pulled out of a 2 day meeting after just one race as I was at risk of being hit from behind. Car is unsafe to race as is.

    The solution seems to be a surge tank near the motor, fed from a lift pump near the main tank, and a second fuel pump from the surge tank to the mfi.

    Before I do so, has anyone ever had a similar problem that wasn't fuel surge? For example, would a failing or shorting fuel pump act like this?
    Cheers, Ryan

    Founder and chief centre cap remover at : ZOLLHAUS / Design driven custom PORSCHE : https://zoll.haus

  2. #2
    Senior Member Fishcop's Avatar
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    Crap, sorry to hear you had to cut the meet short.

    Is this a 'new' problem? Before setting up a surge tank, I'd positively identify the problem doesn't lay elsewhere such as a fuel pump or pump wiring short, or even something like a crimped fuel hard line (from a rock) etc...
    John Forcier
    EarlyS #1987
    1968 911 Race Car "Grun Hilda"
    1969 S/T interpretation "Blau Healer"
    Restoration Saga

  3. #3
    Not new, but getting worse - hence the failing fuel pump comment. Used to happen near 1/4 tank now at 3/4.

    Don't really want to add a surge tank (one more thing to fail, weight etc) but need to get this sorted. Very hard to diagnose as it doesn't happen on a dyno and tough to recreate on the street.
    Cheers, Ryan

    Founder and chief centre cap remover at : ZOLLHAUS / Design driven custom PORSCHE : https://zoll.haus

  4. #4
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    ryan,

    maybe best to start with the plastic tank.

    i just had my 40 year old plastic tank chemically cleaned also removed the microfilters, then had the filters ultrasonically cleaned.

    regards

    peter kaufmann

  5. #5
    Hi Peter,

    Who cleaned your tank?

    And what microfilters are you referring to?
    Cheers, Ryan

    Founder and chief centre cap remover at : ZOLLHAUS / Design driven custom PORSCHE : https://zoll.haus

  6. #6
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    Quote Originally Posted by obrut View Post
    Hi Peter,

    Who cleaned your tank?

    And what microfilters are you referring to?
    i will find out who it was sent to and get back to you , but any good radiator repairer can hot wash it. they could not get mine 100% clean,

    but pretty close. the filters are on the the inlet and outlet nozzles.the surface area of the filters on mine were 80% blocked with krudd.

    i had this tank cleaned about 20 years ago,but no where near as thoroughly as this time.

    this the first time the filters were removed and ultrasonically cleaned,this was done in house, so to speak.

    they came out clean ,although once again not 100%

    regards

    peter
    Last edited by kaufmanp; 09-01-2013 at 04:24 AM.

  7. #7
    thanks peter, very helpful.

    i would be grateful if you could let me know who cleaned your tank.

    did you look into replacing the filters? or they available?
    Cheers, Ryan

    Founder and chief centre cap remover at : ZOLLHAUS / Design driven custom PORSCHE : https://zoll.haus

  8. #8
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    Quote Originally Posted by obrut View Post
    thanks peter, very helpful.

    i would be grateful if you could let me know who cleaned your tank.

    did you look into replacing the filters? or they available?
    ok , i will find out for you and let you know.

    i am pretty sure you can get the strainer/filters, as i have seen them on e-bay, bit pricey for what they are.

    can't remember who vendor was, maybe serria madre...? i would try sunset porsche first for example as they are probably available still.

    i would throughly clean and inspect the strainer/filters you have first.......

    although after doing all this , i did go out and buy another new plastic tank , and kept this one as a spare and/or for later use on the other

    car.

  9. #9
    Senior Member Fishcop's Avatar
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    Hi Ryan, that's a good call by Peter.

    Aviation industry use poly fuel tanks in a lot of aircraft, maybe someone in the Bankstown area can help?

    If you can't find someone down there, mail the filters to me and I'll put them through my ultrasonic cleaner... I also have one or two spares to make sure you get the cleanest ones back.
    John Forcier
    EarlyS #1987
    1968 911 Race Car "Grun Hilda"
    1969 S/T interpretation "Blau Healer"
    Restoration Saga

  10. #10
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