speedometer reads 140mph when im going 70mph?
 

exactly what the topic says. I already searched and found different answers on this problem i am having. someone said its the magnet in the speedometer and others say to just buy a new cable. does anyone have a real answer on this issue, i cant be the only one who had this mechanical problem. So, ya like no matter what my speed is, its like the speedometer is x2 the speed that i know i am going. someone please help me, this is driving f**king crazy!!!:vash:

Is the odometer affected too?

what year car?

its a 1990 i just bought a few days ago. odometer doesn't appear to be affected from what i can observe because i calculated how far i drove last night and it seemed fairly accurate.

speedo is mechanical cable. but unless the digital conversion in your cluster is fubared...

its definitely the old crappy mechanical setup from the factory. what do u think it could be braineack? because i'm guessing it the problem lies in one of three areas: 1.cable, 2.speed driven gear, and 3.gauge cluster

Car is seriously fast. You should make some youtube videos for us, showing the speedo.

lol not funny, but ya it would be funny video

1. Take video of 0-140 (indicated) mph run.
2. Post video on CR.net.
3. Sell car on CR.net.
4. Profit!

In for the 60mph on 1st gear.

tell everyone its LS1 swapped:giggle:

lol omg you guys are serious huh? well that still doesn't solve my problem with a half broke speedo. maybe on my way to work tuesday i will make a video.

its not a common problem. I don't think anyone even knows how to help you short of telling you to get a new speedo cable and cluster

D**n! I didn't wanna hear that. guess I will be buying both to make sure I fix the problem. Might as well buy the European kilometer style LHD face gauge cluster while I am at it, just so I feel satisfied that I will be installing something different then just plain jane replacement part.

Well seeing the odo is not broken then i don't see a reason why it would be the speedo cable.

okay so this is what i discovered. I also have a airbag diagnostic module that needs replaced because the airbag light flashes 10 times...so I crawled under the dash and found the larger of the two baby blue modules, lol it says Ford real big on it of course, then i decided to locate my speedo cable and once i did i gave it a very light tug and the darn thing came right out from the cluster as if it was never connected all the way. I looked inside the plastic coupler and all i see is a plastic rectangular peg, is there something else that is suppose to be there? I mean come on a little plastic peg turns the speedo?

took some pics

https://www.miataturbo.net/attachmen...ine=1343024303
https://www.miataturbo.net/attachmen...ine=1343024303
https://www.miataturbo.net/attachmen...ine=1343024303

yep, the speedo gear in the trans spins that.

does your speedo bounce/shake at all?

it guess it's possible you have the wrong gear installed in the trans, i dont see how the cluster would double the speed, i think it's still mechanically linked, but I know the signal is converted digitally IIRC.

Whats more screwed up is that he says the odometer reads correctly. Isnt the odo mechanically linked to the speedo as well?

My 2c is the speedo it self is fucked.

yeah, which is why my speedo bounces, because the cable is fubared. but I was able to smooth out the routing of it and got it to at least not make any noise.