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Fispa electric fuel pump re-build

Discussion in 'Vintage (thru 365 GTC4)' started by prance, Apr 10, 2009.

  1. prance

    prance Formula Junior

    May 4, 2005
    510
    Agoura Hills
    Full Name:
    morris
    Does anyone know how to dis-assemble a Fispa electric fuel pump so that I can have the coil re-built.
    so far we have everything apart up to removing the core. I can't figure out how to pull out the coil.
    Any help would be greatly appreciated.
    Morris
     
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  3. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,184
    Berkeley, CA
    Full Name:
    Brian Brown
    If the wires from the coil are not broken off, I would not recommend removal of the coil core, as it is very difficult. Is there any remaining part of the wire protruding from the coil core through the body of the pump?
     
  4. prance

    prance Formula Junior

    May 4, 2005
    510
    Agoura Hills
    Full Name:
    morris
    yes there are but the coil is not consistently grounding to the body. I think there is a problem further down with the wires. I think that somewhere the coil should be grounded to the body so it can pick up the negative side of the battery from the chasis. It does not do this.
    when we tested continuity or tried to ground the body the coil won't work, only when we touch the neg. wire from the coil itself.
    Additionally, it will only cycle once. This may be an adjustment problem of the shaft.
    What do you think?
    Morris
     
  5. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,184
    Berkeley, CA
    Full Name:
    Brian Brown
    The coil should never ground to the body, if it is shorted to ground then there is a problem with it. One end of the coil is connected to 12+, coming from terminal stud through the plastic cap. The other end of the coil gets grounded through the set of points that is triggered by the pump plunger/piston.

    When the piston is at the bottom, the point are closed grounding the coil. This energizes the coil and pulls the piston up into the body, causing the points to open. The magnetic field collapses and the return spring pushes the piston back down. This happens over and over until the fuel pump builds up enough pressure to keep the piston from fully returning to the points closed position.

    The only adjustment is the height of the cam for the points operation. You can manually ground the pump right at the points connection to the winding to check the position of the cam at it's uppermost height.

    Did you replace the pump diaphragm? There are many aftermarket diaphragms that are the incorrect thickness/material and will cause the symptom that you describe. T. Rutlands sells a good diaphragm/seal kit that works properly.
     
  6. prance

    prance Formula Junior

    May 4, 2005
    510
    Agoura Hills
    Full Name:
    morris
    Brian, I actually figuered out the above after your last post. I'm going to go back to the shop on Friday and play with the adjustments of the cam. I think that was the problem. I think it never cleared the contact thus not breaking the circuit, which would have aloowed it to re-cycle.
    Yes I replaced the diaphragm with one from Ted. We are also in the process of trying to source the original diaphragm material from the German(I think) company that supplied the ones to Ferrari. I have the name off of the original diaphragm. They are still in business and I would think that it is just a matter of getting the material from them.
    I will let you know of my progress.
    If the wire breaks off in the coil have you ever dis-assembled it to re-wind it?
    It looks like there is a pressed in ring on the bottom that holds the assembly together. We were thinking of making a tool that expands inside the ring and pulls it out.
    Morris
     
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  8. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    2,184
    Berkeley, CA
    Full Name:
    Brian Brown
    I have had the wiring break off before. If it is above the level of the body, I solder new wire to the remaining part of the wire. If it is below the level of the body, I remove the coil and solder new wiring to the existing wiring. I have never had to rewind a coil.

    To remove the coil you must first remove the 2.5mm copper vent tube that goes from the inside of the body to the outside. This tube secures the ring. You must then remove the ring and then the upper cone to get the coil out.
     
  9. jav

    jav Formula Junior

    Apr 9, 2007
    507
    Massachusetts
    Full Name:
    John
    Morris-

    I'm curious, is there a reason you want to source the original diaghragm material? I recently rebuilt my pump twice becuase I learned the first diaghragm I installed was not 100% ethanol compatible... and it was Viton. I presume your doing it so that it is true to it's original form but aren't you concerned about using it with new fuel formulations? Are you perhaps using Avgas?
     
  10. prance

    prance Formula Junior

    May 4, 2005
    510
    Agoura Hills
    Full Name:
    morris
    I haven't personally had any problems with the material but I've heard so much about the eventual hardening of the new diaphragms I thought it would be interesting to go back to the original supplier and see what thier material would do. Id doesn't seem like a dificult or expensive experiment, the key would be getting the material from the original supplier.
    Morris
     

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