No speedo - Fixed!!!! | The Z Club of Great Britain
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No speedo - Fixed!!!!

Discussion in 'Z31 (300ZX) Electrical' started by Northerner, Jul 7, 2018.

  1. Northerner

    Northerner
    Z Club Member

    2D934AB9-508B-4C69-AD25-AB72C7CEE388.jpeg 1F3EBEEA-164A-4890-A649-0330C27C84BF.jpeg I may have a fix for the z31 speedo issue. Mine went dead ages ago so I’ve done the usual testing of the sensor in the gearbox as mine is a facelift which was fine. Even swooped over spare speedo I have which didn’t work. I’ve traced the wires to the speedo head which were all ok.
    I’ve been searching the web for ages and found a thread from a Japanese owner and spent ages using google translator.
    It seems there maybe an issue with the semi conductor which corrodes. Well I opened up my spare speedo after testing it to find the same corroded part. In fact it was green and it was loose. It even snapped off with light pressure.
    Anyways I opened up the one on my car to find exactly the same.
    I’ve ordered a few so watch this space.....
     
  2. Northerner

    Northerner
    Z Club Member

    Got my new resistor today and it was a little tricky to remove and solder in again but got it done. Went for a drive and hey presto fixed!
    For some reason Nissan uses a 9v resistor to obviously drop it from 12v to feed the speedo.
    Unfortunately it means taking out the clocks and totally disassembling the clocks inc taking off the needles but it’s well worth it when done.

    As you can see I used a bolt pressed against the side of the next resistor to help flexing or vibration. The cost was £2 and some patience
     

    Attached Files:

  3. Northerner

    Northerner
    Z Club Member

    Another update! After driving around I have noticed that the speedo is now 10mph out.
    However I noticed an adjustable resistor on the speedo board which was set at 4 dots from the right. So thinking this must be the adjuster I moved it to 2 dots from the left. This made the speedo even more out so I changed it back till 2 dots from the right and using my gps speedo app found it to be 1-2 mph out. Result.
    It meant that I’ve had the clocks in and out several times but it was worth it. See the attached picture to show the resistor.
     

    Attached Files:

    MaximG and Woody928 like this.
  4. mrM

    mrM Well-Known Forum User

    good info ,i hope i never have issues with mine but this is good to remember as a lot of parts are hard to find/expensive these days for our z31s,cheap fixes are cool with me! EXTRA;)
     
  5. scb1957

    scb1957
    Z Club Member

    Hi Northener, My speedo died about 4 years ago and been using GPS speedo, but when I get mine running again, I'll have a go at pulling the speedo out. I have had it out once before and it's a bit of a ballache. Need this power transistor to get mine running, before I can tackle the speedo.
     
  6. Northerner

    Northerner
    Z Club Member

    They are about £2 on flebay. Just make sure sure do a decent solder joint or if not competent take it to a tv repairs! Good luck
     
  7. scb1957

    scb1957
    Z Club Member

    Hi finally got round to sorting the Z31 out. Now have working headlamps and motors and have taken the speedo out to discover the exact same fault highlighted by you. Parts on order from E-bay, as per your photograph. Thanks for your input and info. Cheers Steve.
     
    moggy240 likes this.

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