OntarioTurbo

I just recently checked my speedo with my gps unit and it is consistantly 10 Km (Canada) high. I have used two different gps units and get the same results. The car is completely stock with stock rims and tire sizes. Speedo sensor is not loose and the speedo works smoothly, just always 10 Km high at any given speed.

Any ideas?

bigdeano

Could be out of calibration. What tire size are you running? Altho it would take a big change in diameter for it to be off by 10km but that could be adding to it a little bit.

fbgh2o

I would say that I have the same issue, but in the other direction. My car is a US car, but seems to be about 5 mph slow (at least compared to traffic around here).

Burma Shave

If the odometer gear has been replaced, it could be that the speedo needle was reinstalled slightly off.

JohnKoaWood

+1, open the gauges, move the needle the amount needed, re-verify with GPS..done...

bearone

be careful removing the needle or live with it like most folks do, me included.

87951
95sl320

OntarioTurbo

Sounds like that could be the problem because it doesn't matter what speed you are at it is still 10Km high. When I eventually take my guages apart, I will attempt to move the needle back. I'm glad it's showing high instead of low though. Helps keep me out of trouble.

bigdeano - The tires are stock 205/55/16 front and 225/50/16 rear. I am planning to increase the rears to 245/45/16 soon, but that is pretty much the same outside diameter.

bearone - Thanks for the tip.

bearone

your welcome.

this tire size calculator tells you if any difference from stock tires.

http://www.miata.net/garage/tirecalc.html

87951
95sl320 dd

bigdeano

That's identical to stock tire sizes so I'd say ur safe there, def listen to these guys and check the needle

RolexNJ

And if those don't work it can't hurt to use these guys, afterall our cars are very old. This company does superb work.



http://www.nhspeedometer.com

TurboTommy

Malfunction of the needle is one thing;
But, I've noticed that even when the speedo is working correctly it still reads 5 to 6 % too high. I'm on my third 951 and they were all out about that much.

JohnKoaWood

I have been into my gauges a little, and it really is easy to fix, with 2 fingers and a tender touch you just push the needle in the direction it needs to go.. If it is reading low, swing the needle all the way to teh right, and adjust it the distance it needs to go... I have had mine apart and back together a few times already, and have yet to bend a single needle stalk...on any of the gauges... and my speedo is GPS confirmed accurate to 110...

bearone

reads high??, most folks see it lower than gps.

87951
95sl320 dd

Burma Shave

It is this easy, and I haven't bent one either. No need to remove the needle. Matter of fact, if you do remove the needle to adjust, the chances of getting it right are very slim.

Mike_UCR

I have an 88 924S and my speedo shows high as well. But here's the twist. It is 10km high from 70 - 90kph, 20km high from 100-140 kph and 25-30 km too high above that. Keeps my math skills sharp!