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Hi all,

Can anyone help me or give me advice??
My speedo was jumping up and down while i was driving and suddenly stopped working. (2001 model NB)
I am so scared, has anyone experienced this before?
Is it a cheap fix?

Any advice would be appreciated.
Thanks in Advance!!!

Could only really be 3 things. Speedo cluster, speedo cable or speedo drive.

Did it jump up and down, or down and then back?

Dann

NitroDann wrote:Could only really be 3 things. Speedo cluster, speedo cable or speedo drive.

Did it jump up and down, or down and then back?

Dann

Yea, for example if the reading is 60km it will suddenly drop to 0km for few seconds then jump back to 60km.
But 70% of the time it sits itself at 0km now while driving.

Any clue?
how much is repair?

I'm so scared!!!

either a stripped speedo drive or your speedo cable isnt secured in the guage properly... Im going 95% its the sppeedo drive gear. I couldnt imagine it should cost more than 150 at worst

Dann

If everything else on the dash is working then it's probably not a loose plug on the back of the dash cluster (but is pretty easy to check)

Dann's probably right about the speedo gear, which could be broken, coming loose from the gear box or a dodgy cable connection.

The speedo drive gear is connected to the gearbox and looks like this:


I'm sure forum sponsor MX5 Mania would be able to suss it out for you.

wow... Thanks so much for the info, I will book in a check up at Mx5 mania, as i assume they would have that part.

I noticed that the gearbox (gear stick) is constantly vibrating when driving, so maybe this caused it?
Is this normal?

MX5s tend to wear out the boot(s) around the gear stick every 60,000kms or so, that could also amplify any vibration from the box. If the speedo gear was seizing and grinding away perhaps that could also cause a vibration. Make sure you mention the vibration to Mania so they know it's something else to look at.

My NB speedo is electronic.

You could check the plug that connects the loom to the sender unit on the gearbox, but I doubt it would have come apart as it locks together.

If you're getting an unusual amount of vibration in / through the gearbox, perhaps the pulse generator in the sender unit has shat itself. The drive gear on the sender unit could be stripped, or the gear could also be spinning on the shaft. Best to get someone to pull it out and check.

That really surprises me, the electronic speedo that is..

I have both a 90 model 5 speed and a 2000+ se 6 speed, and both just bolt up and everything is the same, cable speedo included, and I was under the impression that every na/nb box was a straight swap into any na/nb.

maybe they all bolt up and run but the speedo wont?

Dann

The box is a straight swap, but you reuse the NA speedo drive. AFAIK NB is electronic yes.

eg: http://www.miataturbo.net/showthread.php?t=34919

Similar problem on another NB: viewtopic.php?f=29&t=42521

NitroDann wrote:That really surprises me, the electronic speedo that is..

I have both a 90 model 5 speed and a 2000+ se 6 speed, and both just bolt up and everything is the same, cable speedo included, and I was under the impression that every na/nb box was a straight swap into any na/nb.

maybe they all bolt up and run but the speedo wont?

viewtopic.php?f=29&t=46608

booked in for a service and check up at mania tomorrow, will get it all checked up.
Will update you guys when i find out.

Best of luck!

Let me know how it goes, I know someone with a surprisingly similar problem

^ That would be me unfortunately

01 NB8B same as yours.
At first it was dropping out for a few seconds when accelerating then it would come back, but it's now progressed to the point where it can be gone for hours.

Had it up on the hoist last week and gearbox fluid is leaking from the sender itself so I'm fairly certain that's the problem.
Just need to find the time to swap it out.

So whats in the place of the sender on an nb? Block off plate?

Dann