4r70w swap speedo issue

[03TTMO]

I've recently swapped a 4r70w into my 03 cobra. Everything is working great other than my speedometer does not read the correct speed. Not sure what needs to be done to correct this. Any help would be greatly appreciated!! TIA

 

[Four Door SVT]

It's on the tuner to address that

 

[Soap]

It's on the tuner to address that

Correct but that is only if the OP wired everything in correctly. OP....did you wire in the speedo sensor and hook it up to the 4R?

--Joe

 

[VA-Mach1]

You need a speed sensor from a car that came with the same factory gear ratio as yours. E.g.. if yours came with a 3:55 get a sensor for a Mach 1 Auto then use your tuner as normal if you run a different ratio than stock.

 

[Soap]

You will need to adjust your "revolutions per mile" in your tune. But again that assume the OP wired in the speedo sensor correctly so that the ECU is actually getting a signal.

--Joe

 

[03TTMO]

I wired the speed sensor from the 4r70w harness to the corresponding pins on the t56 main plug. I tried to follow wiring harness diagram, but my car has BS3 and twin turbos, most plugs on the wiring harness were not used. It was a little overwhelming I must admit.

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[Soap]

I wired the speed sensor from the 4r70w harness to the corresponding pins on the t56 main plug. I tried to follow wiring harness diagram, but my car has BS3 and twin turbos, most plugs on the wiring harness were not used. It was a little overwhelming I must admit.

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So are you getting a signal at all? If you speedo is just off then it's a simple fix in the tune. If you are getting no signal (speedo does nothing) then you have a wiring issue.

--Joe

 

[03TTMO]

yes I get signal, it just seems to read about half the speed that I am actually going.

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[Soap]

You might be able to fake it in the tune based on revolutions per mile, but if you are half.......you might be beyond the range of correction. Do you know how many pulses the 4R70 reluctor ring is?

--Joe

 

[03TTMO]

That I do not know.

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[Soap]

Quick Google search says it might be 6 pulses........which would explain why your speedo is reading half. Not sure what year 4R70 you have though.

Stock T-56 reluctor is 12 pulses. The number of holes can be adjusted in the tune.

http://www.modularfords.com/threads/148739-04-4r70w-in-an-01-gt

--Joe

 

[03TTMO]

I have got with my tuner and they said they should be able to get it taken care of. Thanks to everyone!

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