Z32 Speedo flipped to opposite side

Discussion in 'Technical' started by mtopxsecret6, Jan 12, 2021.

  1. mtopxsecret6

    mtopxsecret6 Member

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    Hi everyone, I searched the tech articles, and google, and didn't really find a possible answer to my problem. There was another thread with something similar and I responded to it with no reply.
    I took my car for a drive yesterday, and noticed my speedo was on zero, then when I hit 70klms(I have an apexi multi checker which shows speed reading), the needle flipped over to roughly 140klms, it stayed around that figure irrespective of speed over 70klms. Once the car went under 70klms, the needle just drops, as per the photo. When I go over 70klms, the needle jumps back to the 140ishklms mark, and drops when under 70klms etc etc.
    Should I remove the cluster and resolder and clean all the joints etc on the speedo? Im getting a speed signal at the ecu for the multichecker to get a reading, should I visually check the speed sender anyway?
    [​IMG]
    [​IMG]
    there was another post a year ago, though no response to wether he fixed his issue or not.
    Thanks
     
  2. MintZ32

    MintZ32 Active Member

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    Have you recently changed the battery or done anything that could have somehow exposed the cluster to a voltage spike?

    I had this issue when importing a bunch of parts from overseas and two clusters arrived this way. If it is not damaged and has simply received a rogue voltage spike it will need to be reset by seeing a voltage equivalent to approx 140km/h. (the same goes for the tach which is simply reset by revving to around 4.5k-5krpm) Obviously you can do that by driving up to that speed or you could remove the speed sensor and with the vehicles ignition in the on position connect a drill to it similar to as shown in this video @ 4m 50s to mimic the speed.

    Hopefully this resets it to the 0km/h position. If not, you probably have a broken cluster and you may be up for some solder work. good luck.
     
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  3. mtopxsecret6

    mtopxsecret6 Member

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    Thanks for the reply, I did discount the battery terminals and gave the battery a reconditioning charge before this issue arose. I'm not having any heavy steering issues etc etc, just what you see in the photo. Maybe I need to take the car for another drive and see if that fixes my problem?
     
  4. MintZ32

    MintZ32 Active Member

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    The battery thing could very well be the cause of all this.

    You'd only see the heavy steering issue if the problem was caused by the speed sensor sending the ECU a dodgy signal. In this case as your APEX'i display rules that out you can be quite confident the issue lies in the cluster itself. Safely make that cluster read 140km/h somehow and you should have it reset back to normal.
     
  5. mtopxsecret6

    mtopxsecret6 Member

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    Ok, so making the cluster see 140klm + 3 times didnt change anything, still the same. Also I noticed the rpm's are out by 200ish rpm's aswell. The odometer is working, reading other cluster problems I made sure to check that aswell. Ill remove the battery terminal and do a foot brake reset, and see if that changes anything, otherwise I'll remove the cluster and inspect fit.
    On a side note, I think the battery is failing, it struggled to start just now even after giving it a reconditioning charge.
     
  6. MintZ32

    MintZ32 Active Member

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    Hmmm the speedo board may have bigger issues. Perhaps source a spare and try swapping it in. May be easier than attempting the re-solder.
     
  7. rob260

    rob260 Moderator Staff Member

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    The speed signal will pass through the cluster before the ECU, so if you are getting an accurate speed signal at the ECU this suggests that the problem is with the gauge. Suggest opening it up and re solder the circuit board. If you're not confident doing this yourself try taking it somewhere that repairs TVs (if such a place even exists...) or consider contacting Gary from twinturbo.net
    techno@comcast.dot.net and shipping it to him in the states he is a wizard with this stuff.
     
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  8. geron

    geron National Petroleum Equipm

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    Any TV technician can resolder cold solder joints. Easy as and cheap as, do a search on the internet for your nearest TV repair shop.

    Also a good idea to do this on the 30yr old ECUs, there will be cold solder joints for sure by now.
     
  9. mtopxsecret6

    mtopxsecret6 Member

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    Pulled the cluster out, cleaned all the dials rear plastic pcb contact points etc. The speedo looked much newer than the other dials. Anyway, ive ended up with the same results, nothings changed. Time to get a spare cluster to see if its the car or the speedo at this point.
    Photos of the cluster and speedo.
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
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  10. IB

    IB ?????

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    There are a few pads on that circuit board that could do with resoldering.
     
  11. beaver

    beaver southern zeds

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    Y 1-2 X 1-2 look they went over temp, they look burnt to me.
     
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  12. mtopxsecret6

    mtopxsecret6 Member

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    Ive got to pull the cluster back out again anyway, so I might re-inspect the board again.
     
  13. AndyZ32

    AndyZ32 Member

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  14. MickW

    MickW Carntry member...

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    Yes. I spied that with my little eye as well - 2 electrolytic capacitors have been running hot, hence their plastic sheaths peeling back from the tops of their metal cans. Beaver I don't know these circuits as well as you do but could the voltage regulator on the speedo board be suspect? The 1000 MFD cap has to be part of the voltage reg/smoothing.
     
  15. MickW

    MickW Carntry member...

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    Great pics mate! I know what a bitch it is to take pics of circuit boards up close, it's a depth of field nightmare :)
     
  16. MickW

    MickW Carntry member...

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    Sorry, having a quiet giggle as I imagine you being pulled over for speeding.
    "But officer, your radar gun is clearly out of calibration. You and I are both doing over 200 KPH as we speak."
    ( just remember to hide the Apexi module though )
     
  17. MickW

    MickW Carntry member...

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    Thanks Rob, that's handy to know. I assumed the opposite but never really looked into it.
     
  18. beaver

    beaver southern zeds

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    If you can see any damage on electrolytic caps there shot, it usually means some of there charge storing layer (a liquid) has dried out leaked out, and from what I've read 90's vintage electrolytic caps used a defective electrolyte formula, they worked but were always going to fail, unlike ceramic or plastic caps which rarely go bad. Heat, voltage, age, and especially reverse polarity current will kill a E/cap quick smart, causing all sorts of issues, like trashing coupled components.
     
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  19. MickW

    MickW Carntry member...

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    Amen. Bulging tops or plastic sheaths shrinking back from the top edges, and a greasy stain under the cap if it's vertical to the ground, are the signs to look for.
    Not many electronic components give us a visual clue that they're failing but bad electrolytic caps are easier to spot. Still, they can look good but still be bad.
     
  20. mtopxsecret6

    mtopxsecret6 Member

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    I bought a spare cluster, and swaped the speedo over into my original cluster. The speedo is working like it should. Though its still reading 10% out. How do I tell what diff I have? As my rear end has been changed to remove the hicas stuff. Would a different diff or speed sender with the wrong gear spur give me a 10% difference? The speedo is reading 10% more than I am actually physically driving. Guess I'll never get any speeding tickets I spose.
     
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