I've replaced the original auto tranny in my 1988 Fiero Formula with a 1990 Getrag 5-speed tranny from a Beretta. The speedometer reads way too high as connected so I purchased a Dakota Digital SGI5 C. The directions are not clear to me as to where the convertor is to be installed and where it interfaces to the vehicle computer and dashboard. Can you give me any assistance or diagrams?

I realize this has been previously discussed but I could not track down a clear point to point (pin) description of how to connect the SGI-5-C to the Fiero computer in the center console and to the speedometer connector in the dash gauge assembly. I sure would appreciate some help. Thanks in advance.

Welcome to the forum!

This archived thread has the info you need:
https://www.fiero.nl/forum/A...120111-2-091336.html

Another option is to run a $75 Dakota Digital signal inverter.
Cut the Yellow VSS wire in the center console before the 203.
Connect the YELLOW from the VSS sensor to the INPUT.
Connect the YELLOW going to the 203 to OUT 3.
Connect the POWER (Red)
Connect the GROUND (white)
Switches 1, 2, 3 & 4 are all positioned down.
Then drive the car at a known speed and use the UP/DOWN buttons to set the speedo to the actual road speed.

[This message has been edited by fieroguru (edited 02-05-2018).]

If the speedo is reading high, it is hooked up correctly, just not programmed correctly (via switches)

The Fiero transmission outputs a 4000 PPM signal. The later transmission outputs a 24,000 PPM signal. So it should be reading 6x high until the switches are set correctly.

Thanks for you reply but I haven't installed the SGI-5C yet. The original wiring when connected to the Beretta Getrag reads high. I'm waiting for a nice day to install it per your earlier suggestions. I'm still a little "fuzzy" about what pins I need to connect to from the vehicle computer but perhaps it will be more clear once I tear into things.

What specifically is the "203" you refer to? Connector? Pin? Thanks

Remove the center console to expose the ECM. At the base of the ecm is a 2 plug connector called the 203C. The yellow wire you want to splice into is pin G.

Isn't there a way to use the Fiero gear and speed sender on the Beretta Getrag?

quote Originally posted by pmbrunelle: Isn't there a way to use the Fiero gear and speed sender on the Beretta Getrag?

Yes. Split the case, knock off the reluctor wheel and install the VSS gear from a Fiero Getrag

Thanks for your help with the C203 pinouts and the SGI-5_c. Got it working today!