Hey guys, got a question that I'm hoping someone here can answer before I go to asking Dakota Digital about.

I bought their SGI-5 box and the sensor for the T-5 swap that I put in my car along with the 350. Everything is hooked up like I think it's supposed to be, however I'm getting some erronious readings through the speedometer. Sometimes while sitting still the speedo starts to read anywhere from 10-40mph sometimes as high as 50, but once I start driving though it works fine. It's not a really big problem, just getting to be a real nusaince.

thanks for any help or ideas.
mos

 

It happens to my speedo as well.

My current speedo is an aftermarket digital unit. It was installed before I had a need for the DD Box and the readout was always perfect. I needed to add a DD box to re-calibrate the speedo signal after a T56 swap. I basicaly removed the factory buffer and installed the SGI-5 in it's place. Now it will show that I'm doing 40MPH at a stand still from time to time. It's not a steady speed, but it jumps around while the cars warming up. Start rolling and at about 4-5 miles per hour it corrects itself and is fine while in use.

I was never sure if it was something I did while installing stuff, If it was the tranny sensor, the SGI box, my original cluster, or the Aftermarket speedo that was causing the problem. ) It never really bothered me enough to track it down !

I do seem to recall something about the box picking up some "interference" or something like that. I wonder if I still have the SGI paperwork ??

 

I'm wondering if it has something to do with the AC signal used from the sensor. With it using AC instead of DC it'll tend to be more sensitive to localized interference. I might be able to get rid of it with a small bit of parts to act as a buffer, resistors or capacitors. The only other idea I have is to change it from the AC to the DC and hope that it still works afterwards.

 

I just found this on the web<



Speedometer will read when the vehicle is sitting still.

Tach wire too close to speed signal wire. Route the speed signal and tachometer wires away from each other to avoid interference.

Or

Signal In and OUT wires routed too close. Ground interference. Route the input and output wires away from each other to avoid feedback. Make sure the speed sensor and SGI-5 are grounded together.

Or

Sensitivity set incorrectly Turn switch #2 ON

 

I'll double check on the first idea, but I don't think that's the issue. The other two are good ideas that I'll check for sure since I can't remember how I routed those wires down there in the console or if I did anything with that #2 switch.

 

I tried the switch #2 and it completely shuts off the speedo until you get higher than 40 mph. I have to get some work done to try to get my heater working again tonight, if I can I'll try to look at the wiring and see if I can work on the routing or just change the AC to the DC.