Issue with F40 Fuel Gauge | FerrariChat

Issue with F40 Fuel Gauge

Discussion in '288GTO/F40/F50/Enzo/LaFerrari/F80' started by Boxer365, Jul 14, 2008.

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  1. Boxer365

    Boxer365 Formula Junior
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    #1 Boxer365, Jul 14, 2008
    Last edited: Jul 14, 2008
    I am having a problem with the fuel gauge on the F40. When it is reading empty it is really half full. Have tried filling from both the right and left hand side and in both cases it will only take 55-58 liters. Any suggestions ?

    (I have also tried opening both fuel caps so it will better vent but this does not seem to have any effect)
     
  2. Remy Zero

    Remy Zero Two Time F1 World Champ

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    seriously, i never thought or realize the f40 has to 2 tanks. just realized after reading your post.

    maybe, it's a faulty fuel gauge then?
     
  3. greyboxer

    greyboxer F1 World Champ

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    If its anything like the 308/328 the gauge is fairly random - you should have a reserve light - why not try driving to that once so that you know how the gauge reacts at the low end and at what sort of mileage - there should be about a 3 gallon reserve
     
  4. 410SA

    410SA F1 Veteran

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    The F40 has one fuel tank, but two fillers, on either side of the car
     
  5. TimF40

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    #5 TimF40, Jul 25, 2008
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  6. joe sackey

    joe sackey Five Time F1 World Champ

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    Correct.

    For the USA cars the left hand side tank is more substantial (#143444) and the right side tank is slightly smaller (#143445), but it is common knowledge that there are 2 tanks...
     
  7. 410SA

    410SA F1 Veteran

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    #7 410SA, Jul 25, 2008
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    They act together however? They are joined with a common connector and the fuel feed to the engine comes from one place? Not like the old Jags where you had a to flip a switch to change tanks.
     
  8. TimF40

    TimF40 Formula 3

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    Each has its own fuel pump. Don't know if each pump feeds its own bank or whether they join someplace else. Seems like the engine is two separate 4 cylinders with most everything duplicated. I'm sure the experts on the thread will elaborate on how it really works. - Tim
     
  9. Boxer365

    Boxer365 Formula Junior
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    It is a Euro F40 with twin bag tanks. Given that they equalize when you draw them down, not sure why the fuel gauge is not reading properly.
     
  10. TimF40

    TimF40 Formula 3

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    Is there only a single fuel gauge in one of the tanks, or is there one for each tank with the computer averaging them out for the gauge? I wonder if the cars ever have a problem with the connector hose between the tanks getting clogged or pinched. Hmmm... - Tim
     
  11. Boxer365

    Boxer365 Formula Junior
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    Don't know on the single fuel gauge....

    In terms of the connector hose, the tanks seem to be equalizing properly as I have filled them from both sides and then checked the other. If one side is full, then the other is as well.
     
  12. greyboxer

    greyboxer F1 World Champ

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    It sounds more and more like post 3 applies........
     
  13. Boxer365

    Boxer365 Formula Junior
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    Only one issue in the post 3 reco, the F40 does not have a reserve light on the fuel gauge.
     
  14. greyboxer

    greyboxer F1 World Champ

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    I'm not trying to doubt you and I don't own one of these fab machines and I accpet there are variations but why then is a reserve shown on the drawing above and a light referred to in at least the Euro 1990 handbook (page H4 # 26) ?
     
  15. TimF40

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    #15 TimF40, Jul 30, 2008
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  16. joe sackey

    joe sackey Five Time F1 World Champ

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    Tim you've got your work cut out in this thread what with all the clarifications you're having to make to remind owners that there ARE 2 fuel tanks, and that there IS a fuel warning light. Im bracing myself for whats coming next... perhaps they are just testing you.

    Good job!
     
  17. TimF40

    TimF40 Formula 3

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    Heck, I’ve learned about so many little variations between US and Euro F40s that I can only be sure of what my car has. I’m almost 100% convinced that there’s some F40 out there someplace that’s wired or built differently than what I’ve ever seen, or what the manual says.

    Half the fun about these cars is in learning how Ferrari actually made them semi one-offs from time to time as they incorporated changes, or whatever parts they had in the bin at a particular time. :)
     
  18. joe sackey

    joe sackey Five Time F1 World Champ

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    True...
     
  19. RufMD

    RufMD F1 Rookie
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    You're right on the money Tim....despite what some may proclaim, there are no absolutes with handbuilt cars. In some cases, variations to F40's depends on who was working the line that particular day. Case in point, the location of the clutch bleed valve....certain serial numbers have them accessible from the topside of the engine, others are piped to be access from below only. Spent an hour looking for it once based on where the manual said it should be, only to be informed by someone that based on its build date, it was located elsewhere.

    Such is the beauty of a hand built :)
     
  20. RufMD

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    #20 RufMD, Jul 30, 2008
    Last edited by a moderator: Sep 7, 2017
    Boxer,

    In the diagram below of the Euro F40 fuel tank system, part number 21 refers to the fuel gauge from the tank side, and is found on the left side only. This may be the culprit in the form of faulty sending to the fuel gauge instrument. If there is anyway you can check the action of this part, it might help you. Part number is 139703
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  21. RufMD

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    #21 RufMD, Jul 30, 2008
    Last edited by a moderator: Sep 7, 2017
    This issue brings to attention another interesting difference between USA and Euro F40's, other than the bag tanks found in euro models. The USA fixed tanks have fuel pumps within them. Euro versions have fuel pumps inline separate from the tanks ( #5 in the first pic showing the Euro fuel system) The second pic is the USA fuel system.
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  22. johnvwatts

    johnvwatts Formula Junior

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    Had exactly the same happen to my (euro) F40 today. Put 25 litres in gauge read 1/4 ish initially then zero with reserve light after 10 mins.
    Guess its the sender unit . Did you find a solution to your problem?
     
  23. Boxer365

    Boxer365 Formula Junior
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    Many thanks. I believe I can access the part through the bulkhead behind the seats. I am traveling right now but will take a look next week when I am back.

    I will also check on the reserve tank light on the fuel gauge but am 90% sure there is not one on my gauge (the mysteries of hand built cars).
     
  24. RED HEAD

    RED HEAD Karting
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    I am going to double check but I don't think I have a reserve light either......(in fact I am 99.9% sure). Mine is an early 1990 Euro car (originally Italian).
     
  25. zsnnf

    zsnnf Formula 3

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    The low fuel light comes on in my car when I have almost 10 gallons left. I just figured they wanted to give me PLENTY of warning!?! :)
     

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