Speedometer Off

[tjmaxx]

I have a 4.10 gear in my 96 gt, I have a speed calibrator to fix the speedometer being off but my question is can I just purchase a tuner and fix the speedometer? I think the answer is no?

 

[trinity_gt]

I have a 4.10 gear in my 96 gt, I have a speed calibrator to fix the speedometer being off but my question is can I just purchase a tuner and fix the speedometer? I think the answer is no?

You are correct.

 

[tjmaxx]

That sucks lol

 

[Rusty67]

If you remove the speed cal and use a tuner you should be able to set the gear ratio in the tune. You just need a tuner capable of changing the gear ratio.

If your speedo's calibration is off a tuner can't fix that but if it is just a gear ratio issue then you should be fine.

 

[m0squ1t0]

what about from a gauge swap (160mph svt cluster in gt) how to calibrate for that

 

[Deleted member 38176]

That sucks lol

Remove whatever "speed calibrator" you have and a tuner will correct it.

 

[wmburns]

I can see from the wiring diagrams that for the 98 and older Mustangs, the VSS sensor output goes to BOTH the PCM and the cluster.

For the 99+ MY, the OSS sensor output goes to the PCM only. The PCM sends a speed command to the cluster.

To me, that implies for the 98 and older Mustangs that a tuner can not be used to correct for axle changes. Because the tuner would correct the PCM speed but the cluster would still display the wrong speed.

The turner works for the 99+ because once the PCM has the correct speed, the cluster has to be correct.

Regarding the question about the cluster swap, the answer is different depending upon the MY.

 

[Rusty67]

I didn't realize the earlier SN95 fed the dash directly from the VSS, looks like trinity was right on with that and wmburns strikes again with the mad knowledge.

What year cluster are you going to swap in ?