Help with speed calibration showed in VCM scanner

[Mysta Joe]

I have researched but cant find a similar issue to mine.

Here's the situation, C5 corvette LS1 with PCM and DBW in a RX7, T56 from the corvette converted into Fbody type, with a T56 Electronic Speed Sensor for a 93-2002 Camaro / Firebird. The car starts fine, drives fine, etc.

After market speedometer gauge from Speedhut, calibrated using a phone GPS app. When logging in VCM scanner the speed in the scanner is about double the actual speed I am going. Any thoughts on how to get the PCM to read the correct speed and show it in the scanner? Will the speed being off in the PCM/scanner affect when I am trying to tune?

I see most peoples problems are where the gauge is reading wrong, but scanner is correct.

Appreciate any help/advise anyone has.

[wilecoy398]

Did you find a solution for this? I have a '90 Corvette that is doing the same thing.

[dermotw]

post tune...! Otherwise not easy to say.

[wilecoy398]

This is the tune. Rusty42217.hpt

[mrpaul55]

did you figure it out

[wilecoy398]

Not yet.

[sshamu]

I have researched but cant find a similar issue to mine.

Here's the situation, C5 corvette LS1 with PCM and DBW in a RX7, T56 from the corvette converted into Fbody type, with a T56 Electronic Speed Sensor for a 93-2002 Camaro / Firebird. The car starts fine, drives fine, etc.

After market speedometer gauge from Speedhut, calibrated using a phone GPS app. When logging in VCM scanner the speed in the scanner is about double the actual speed I am going. Any thoughts on how to get the PCM to read the correct speed and show it in the scanner? Will the speed being off in the PCM/scanner affect when I am trying to tune?

I see most peoples problems are where the gauge is reading wrong, but scanner is correct.

Appreciate any help/advise anyone has.

My issue is very similar. During a datalogging session it says i'm doing 158+ mph when my actual speedometer says 60 mph. The other issue I'm having is my transmission shifts EXTREMELY quickly all the way to 4th when i'm doing 20mph. I'm wondering if the incorrect speedometer signal is causing the quick shifting.

[blyne3]

go set the tire/gear wizard under Edit at the top, I'm guessing you have bigger than a 7.8 in tire