Speedometer issues ... is this common? ---

[alwayscode390]

I was driving today and I noticed when I was doing about 40mph the speedo would die and go to ZERO for a couple seconds then jump back up. It did this the last time I drove the car too.

I have rear gears , not sure if that will do something ... and I am pretty sure I have the speedometer recalibrated for that, and the wheel/tire difference from stock.

Is this a common issue?

What should I keep an eye on to fix?

Ive just had the car for 2 weeks, so figures I am figuring out why the last owner wanted to sell it?! LOL

Its a 2001 GTS, thanks ---

 

[Mad Max]

Have the battery checked.

 

[SingleMalt]

Probably the battery, but if you can get under the car, check the plug going into your transmission towards the tail housing (reach up -- I *think* it's on the passenger side) -- anyway, the wiring may need some work or a loose connector or...

Good luck and enjoy the car!

 

[alwayscode390]

WOW, the battery? Why would that affect the speedo?

The volt gauge stays pretty strong, but I will do what you guys are suggesting and check out the battery.

Thanks ---

 

[Ray W]

Your aftermarket speedo calibration box may have a loose connection or is going bad. Most are located behind the driver's side front fender vent.

 

[alwayscode390]

Are they usually in cab or under the hood?

Can you calibrate the speedo with the SCT tuner by just plugging it into the OBD2 port under the dash ... requiring no "box"?

I'm not sure how the previous owner went about calibrating or tuning this car, but I bought a SCT tuner and plan on getting it re-dyno tuned soon.

Thanks ---

 

[Ray W]

On Gen I and II you need a box. Unitrax sells them custom to your rear gear and tire diameter. Most are mounted outside in front of the drivers door. You will need to remove a metal access cover to get to it.

 

[anaconda666]

If you have an AEM ecu you can calibrate through programming. Not sure on others.