Results 1 to 9 of 9
  1. #1
    Join Date
    Feb 2007
    Location
    Billericay, Essex, England.
    Posts
    864

    Spiyda Fuel Gauge Wizard

    Hi all,

    I have a Spiyda fuel gauge wizard fitted to my car (fitted over a year ago - you know how long jobs can take sometimes!) and whilst the reading seems to be ok, the needle has slight movement in it. It's a kind of "shivering" motion. Just to the left and right a couple of mm. Also, every now and again it will drop a bit and go up again. It will do this weather the engine is running or not.

    Anyone else had this?

    I have eliminated dodgy earths etc by bench testing it all with the battery away from the car so I know it's not that.

    It's a Stewart warner gauge and a VDO tube sensor.

    Just wondered if anyone else had the same issue with one of these?

    It may be that I need a new wizard but thought I'd check if anyone else had experienced this first.

    Many thanks

    Sean
    Too many idiots, not enough villages!

  2. #2
    Sean,
    the later MK4s have 8 times the resolution, so much less in the shimmering department

    Chris
    Spiyda Ltd

  3. #3
    Join Date
    Nov 2007
    Location
    Chester
    Posts
    613
    I've got a mk4, a vdo sender and smiths gauges and it does the same. I have my dampening set at max, position 8, been meaning to drop it to 7 to try that position just in case the circuit is a little sensitive at higher range. Absolutely useless at mid position. All said though, a far better set up than just the float arm system.

  4. #4
    Quote Originally Posted by alunwill View Post
    I've got a mk4, a vdo sender and smiths gauges and it does the same. I have my dampening set at max, position 8, been meaning to drop it to 7 to try that position just in case the circuit is a little sensitive at higher range. Absolutely useless at mid position. All said though, a far better set up than just the float arm system.
    If one of you is down my way ( stourbridge , west mids) some time, happy to put a meter on it and see if we can get it smoother..
    I could just add another level of damping, but I'm not sure thats the problem in this case.. more likely to be fluctuations in the power supply...

    Chris
    Spiyda ltd

  5. #5
    Join Date
    Nov 2007
    Location
    Chester
    Posts
    613
    when I get a chance, I'll put a scope on it and see what noise is around on the supply. What's the minimum supply which these circuits are stable at?

  6. #6
    The wizard should be stable as it is internally regulated down to 5V which supplies the chip and the current to the sender. Apart from the 5V regulator, everything is digital. It will be intersting to see if any noise is getting through the regulator into the line to the sender, but my first guess is its the noise going into the gauge itself. Gauges are built for a 10V stabilised supply, (5V Ford) or straight off the nominal 12V.
    I've not seen the problems described before. Duplicating it on the bench will bne the real answer. Second guess is an error in my maths, the algorithm that does the damping isn't that complicated, but I did write it at the end of what turned out to be a long project.

    Chris

  7. #7
    Join Date
    Nov 2007
    Location
    Chester
    Posts
    613
    finally got round to checking the system noise today. Although there is some, it shouldn't be an issue. Checked it at idle and also at revs and whilst stationary needle movement was not an issue. It does look to be a damping problem because it's when there's physical movement of the sender that the gauge flicker occurs. Forgot to drop the damper setting to 7 rather than 8. I'll get that done some time this week and post the results.

    Al

  8. #8
    Quote Originally Posted by alunwill View Post
    finally got round to checking the system noise today. Although there is some, it shouldn't be an issue. Checked it at idle and also at revs and whilst stationary needle movement was not an issue. It does look to be a damping problem because it's when there's physical movement of the sender that the gauge flicker occurs. Forgot to drop the damper setting to 7 rather than 8. I'll get that done some time this week and post the results.
    If it still has the problem afterward, I'd be grateful for the loan of it back with your settings on it..
    That might help me track down the problem,
    I will certainly update it to the latest firmware too.

    The next version is identical electrically, but has a couple of refinements to the board to allow us to use plugs to program the chip rather than a horrible clip that clips over the legs of the microcontroller. The firmware does have a couple of tweaks to the maths though, so that might solve the problem.

    Chris

  9. #9
    Join Date
    Nov 2007
    Location
    Chester
    Posts
    613
    Yes I'm fine with that. If no joy once the setting is changed I'll drop it in the post.

Tags for this Thread

Bookmarks

Posting Permissions

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