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And yet... Another 355 Spyder Top Problem!

Discussion in 'Technical Q&A' started by TheOriginalJimC!, Jun 13, 2004.

  1. Since I purchased my '98 355 Spyder earlier this year, I've noticed that the drivers seat does not move forward very much during top cycling. It's really not enough to prevent interference with the seat. So, this weekend I ran both seats back to the rear stop and then cycled the top while recording the temporary forward positions of the seats.

    The passenger seat moves forward a bit over 3", then returns to the rear stop.

    The drivers seat moves (a whopping) 1", then returns to the rear.

    I've heard of the position sensors flying south and not coming back, but this seems more like a calibration problem.

    Has anyone had this happen to them?

    Does anyone know if you can do anything to allow the sensor to "re-learn" where it should be?

    Thanks!
     
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  3. Diablo

    Diablo Formula Junior

    Bring it to the dealership and have them perform a complete cycle test with the SD1.

    If it all looks good and it still happens, you will need a seat potentiometer.
    (avail separately in Europe), you will have to buy an entire seat rail if in the U.S.
     
  4. Dem

    Dem Formula 3

    Mar 21, 2004
    1,025
    London
    Full Name:
    Dem
    Sounds like a similar problem to mine. As I mentioned in another thread, the dealership recommended disconnecting the potentiometer which should allow full travel of your seat on the seat button. If nothing else, this will help you determine if it is indeed the seat potentiometer which has gone or not!
     
  5. malibumk

    malibumk Karting

    May 14, 2002
    167
    Malibu, CA
    Full Name:
    Mike Klein
    Jim:
    They move to pre-determined positions and the pass side always moves farther....I guess they assumed the driver was taller....

    But if in fact the to is hitting the seat thaen someting is wrong. If not, it's ok. When the seat potentiometers fail....you will see a clear problem of on sort or another.

    The preset positions are set with the SD-1...and they could be off if someone replaced a pot and didn't recalibrate. Plan on about 1hr labor...and only the dealer can set it (or someone with an SD-1). But if they want to put mega$$ parts in there....run. There are plenty of cheap fixes.

    MK
     
  6. Mike:

    I think you nailed it. All in indications are that the system is functioning normally but the drivers seat just does not move as much as it is supposed to. I recently looked at another spyder whos driver seat practically pinned me against the steering wheel before the top cycled. Maybe the previous owner of this car was tall, and had someone reprogram the seat position so he didn't get "squashed" when ever cycling the top.

    I've been put in touch with someone who knows 355's like the back of his hand and will discuss the situation with him on Monday. If I get any additional information, I'll follow up to the thread. If reprogramming works, you guys will be the first to know about it!

    I do love this car. But this seat/top combination is simply stupid. I would love to have the fully adjustable manual seats with the lumbar support and a top that was simply manual. It would probably take some weight out of the car also!!!

    For anyone out there wishing to know how to fill the hydraulic fluid reservoir for the power top, send me a private email. It's very easy once you know the steps.

    Jim
     
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  8. Here is an updated to the seat story...

    A few nights back, I visited a friend who has an SD-2. We connected to the top/seat computer. (The connection is at the computer located on the side of the hydraulic mech, located under the cover between the seats.)

    The seat position sensor for the passenger seat appeared to be working fine but the drivers seat gave bad readings, and basically didn't change as the seats were moved fore and aft.

    Figuring this could mean the computer was flakey, the connections were flakey, or the potentiometer was bad, I decided to take a look at the actual position sensor.

    There are two connections located on the underside front of each seat. One connection for the seat motor, the other for the position sensor. The position sensor is basically a ~5k potentiometer. The center pin is the wiper and the pins on either side are the ends of the resistor- as one would expect. I measured the resistance with a meter, and sure enough, the wiper appears to be open. I measured the passenger seat potentiometer the same way while moving the seat and it measured just fine.

    At this point, I don't know if the wiper of the pot is bad or the drive hole in the center is stripped out. I'll have to pull the seat before I will be able to tell.

    For a fix, I connected an external 5K pot to the computer side of the position sensor connection under the seat. I then adjusted the pot such that the computer thinks the seat is forward of the point where it thinks the top will hit the seat when it folds back.

    The cool thing about this fix is the top operates fine, and the passenger seat cycles fore and aft normally, but I control the drivers seat manually. I know that in my normal driving position the seat is clear of the top- and unlike most 355's, now I don't get run up against the steering wheel when the top cycles.

    I'll start the search for a new potentiometer tomorrow, but doubt I'll put it in soon!
     
  9. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    4,629
    Full Name:
    Dave Helms
    Common failure is the drive for the pot. Design was destined to fail early.
    Dave
     

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