wrong speed displaed on speedometer GTZ 1992

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ranausaurus
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wrong speed displaed on speedometer GTZ 1992

Postby ranausaurus » Thu Mar 01, 2018 5:25 am

Hi all, I bought a GTZ 1992 1 month ago and there is a huge difference between the real vehicle speed and the displayed.
when I made 120kph real by GPS it showed 135-140kph but the computer is the good one, the cluster gauge, tire size, transmission too.
can it be the VSS ?


thank you ;)



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themixer
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Re: wrong speed displaed on speedometer GTZ 1992

Postby themixer » Thu Mar 01, 2018 12:21 pm

more than likely the cluster itself, using a obd 1 scan tool you would be able to see the VSS speed



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ranausaurus
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Re: wrong speed displaed on speedometer GTZ 1992

Postby ranausaurus » Fri Mar 02, 2018 6:53 am

ah ok I will see it, thank you



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Re: wrong speed displaed on speedometer GTZ 1992

Postby Bapsu » Sat Mar 03, 2018 6:50 pm

20kph difference between wheels and gauge is quite normal... just get used to it. :)



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Re: wrong speed displaed on speedometer GTZ 1992

Postby woody90gtz » Sun Mar 04, 2018 11:38 am

You can adjust it in the tune if needed.


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ranausaurus
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Re: wrong speed displaed on speedometer GTZ 1992

Postby ranausaurus » Mon Mar 05, 2018 3:03 am

I'm planning to get parts from moates to adjust the road speed constant ;) but 13-15% of difference in stock, is quite high.



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Re: wrong speed displaed on speedometer GTZ 1992

Postby 3X00-Modified » Wed Apr 11, 2018 6:31 am

Is it a constant % off? If so then it could be just the needle has moved and isn't pointing to real zero.

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Rettax3
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Re: wrong speed displaed on speedometer GTZ 1992

Postby Rettax3 » Wed Apr 11, 2018 5:43 pm

3X00-Modified wrote:Is it a constant % off? If so then it could be just the needle has moved and isn't pointing to real zero.


???
If it is a constant %, that is a ratio problem -reluctor-ring tooth count, mismatched gauge, ECM, something like that. A constant kph off would be a misaligned needle...
Moates is likely the best route to go to fix it. Although a Dakota Digital SGI-5 (I think they are up to a -5E now, I've used the -5C models before) lets you reprogram the VSS ratio (and even signal types, like sine-wave to square or vice-versa) and is a reliable, quality part. Usually costs around $50 U.S.


1989 Super Charged 3800 Series II (First)Six-Speed Conversion GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26

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Re: wrong speed displaed on speedometer GTZ 1992

Postby 3X00-Modified » Thu Apr 12, 2018 11:06 am

That's what I meant, a constant amount, not %... I don't know why I put that in there.




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