I solved my problem with my SGI-5 on my T56 swap. I thought this info might be useful to someone else. I have a '89 Firebird TPI so it came factory with the electronic speedo.

My problem was when the car was idling, the speedo would pick up interference and read anywhere from 20 - 125 mph!!!!! I tired twisting the signal wires from the transmission like the instructions said, but that didn't fix a thing. After a couple of phone calls to Dakota Dig. and some testing, I realized that my interference was being picked up on the 12 volt power wire that goes to the SGI-5. I was getting my power source from my radio harness. I don't have a radio in the car. When I ran a wire directly from the battery to the SGI-5 all the interference went away. Don't ask me why this fixed the problem, cause I don't know. It may have something to to with my Accell coil.


Good luck,

 

Good info, I'm in the process and hope not to run into much trouble with the speedo stuff....

Can I ask what gears you are running and how you set your switches and what 'outs' you used?

Maybe an electrolitic capacitor on the power wire to ground would help get rid of any interference. Just a thought...

 

I used power from a thick brown wire by the vent/AC controls...no problems there. My box is located under my console.

 

I'm using 3.42 gears. I also used Out 3. Out 4 did not work. Switches 1 & 2 need to be off. Offhand I don't know how 3 - 10 are set. Just drive next to someone, note the difference in speed and use the calculation in the instructions.

I'm not sure how the capacitor would work. I don't have that specific of knowledge in that area.

james_85Z28, do you have a stock ignition coil?????










Tom

 

right now I'm running off the stock HEI setup. My MSD is disconnected for the time being.