140mph speedo problems

[Dan P.]

Well I got the speedos swapped out and went for a drive. The speedo is off, it reads too fast. It also tends to jump a little while slowing. I need to know what needs to be done in order to fix this. I have the stock 15" rims, 3.73s and a auto trans.
Thanks
Dan

 

[Mustang5L5]

You sure it's a 140MPH speedo and not a 85MPH speedo with a 140 face?

If you direct swap a 140 in for an 85 there is no need to calibrate anything. The calibration exists in the mechanism itself

 

[Dan P.]

You sure it's a 140MPH speedo and not a 85MPH speedo with a 140 face?

If you direct swap a 140 in for an 85 there is no need to calibrate anything. The calibration exists in the mechanism itself

I am sure its a 140mph

 

[Mustang5L5]

Yes it is. But it still should be a direct swap. It should not read faster at all.

 

[Dan P.]

Yes it is. But it still should be a direct swap. It should not read faster at all.

I may have put the cable in there wrong I will have to check in the morning. Thanks for the info.

 

[rgosulliv]

my 140 reads 2-3 mph faster when i checked it against the police radar display on the road... doesnt bother me though

 

[mightypoof]

you could take it to a speedo shop and pay like $75-100 to get it calibrated if it really bothers you.

 

[Bearded Forever]

I may have to recalibrate mine.