I have 91z28 with t56 and hooked up a dakota digital SGI 5 box last year. i was having ignition troubles the last few days and dissconnected the MSD box and coil. Wwll, now that i am running the stock coil, my speedo needle is nuts. at idle it reads between 40-70mph. it will drop to zero if I put a draw on the battery like truning the wipers or defrosters on then it will go back to its wired readings. what gives. i looked at the switches and they are right. BTW, the gauge reads a little low while driving. I am not concered about that since that can be fixed with switch adjustments. I just want it too read zero at idle. I must put 10 miles on my odemeter at a stop light

 

haha, mine did that too, turned out i had a bad connection for +12V. also check ur ground.. i just connected it to another power source (make sure its always hot, well mine has to be always hot anyways) and check the ground and try it again.. also make sure u are running ur source wires from the tranny away fromo anythng that might cause interference

 

What output are you using? I'm going to try output 1 to get it to read better because on output 3, the speedo onl read half of actual speed! The SGI-5 is a pain in the ****! Oh well, it's the only thing to get a speedo working, dont get the cyberdyne box, it's a pile of cr@p!

Mike (1bad91Z)

 

im using output 3. i think. what are ur settings on it? and what gears are u running?

 

Sounds like you are getting interference. I don't remember exactly what the instructions said to do to avoid interference, but it involved twisting the ground wire around another wire (input maybe?). Anyways....go back and see what the intructions said. That definitely sounds like interference. By the way, where did you run the wiring through/ where did you mount the box?

 

ok i just went out and looked at my box and i remembered a few things..

out 3 HAS to be used. u need 4000 pulses per mile with an AC output for the VSS.. which means switch #2 needs to be on (UP).
(don't use output 4 like they tell u to, they are wrong about that)

however i think i know what ur problem is. the zero's on the car mean the switch is ON (UP)!!!! not down like you would think it should be. which means ones are OFF(DOWN).

this is one thing that screwed me totaly for the first 2 days. i thought 1's were on values and 0's off. like u would except!! but it was the opposite, and when i figured that out things worked just fine..

so remember:
switch one DOWN,
switch two UP
ones mean DOWN, zeros mean UP


good luck! if u have any more questions then ask

 

Right now I am running out of OUT 4. my switches read as follows 1-3 are off and 4-10 are on.. . I have the directions in front of me and it says OUT3 is 8000ppm AC. OUT4 is 4000ppm oc (what does oc mean) and OUT5 is 2000ppm oc. the speedo reads real low while driving. i have 3.73's in the rear for whoever asked. I have my box mounted under the radio on the trans tunnel and the wires for the VSS run thru the trans tunnel to the tranny. the ground is on one corner of the mounting screw for the box and the 12V is run to an IGN in the fuse block. I will try OUT3 tomorrow and post my results

 

out 3 is definatley what u want.. i was looking it up on the tranny board and all the guys there use out 3. Out 3 is for A\C current which is what the t-56 speed sender uses and what our VSS buffer requires. Im not sure what OC stands for though..

i don't know about other people. but i had to run my 12v hot at all times. or else it would reset the box somehow, and i would have to disconnect it and reset all the numers to off and connet it back and reset the numbers to what i needed. i still dont' understand why it was doing that though..

 

breathment, thanks for the help. i will re wire it tomorrow in the right output spot.

 

OC is open collector. Instead of going to 0V when the pulse is "off", the circuit opens instead.

AC would be 12V - 0V - 12V - 0V
OC would be 12V - open circuit - 12V - open circuit.

The two wires you are supposed to wrap are the signal wires coming from the transmission mounted VSS. I did that on mine and it works great.

 

Ok, sorry to take so long to get back with my results. I am now running out of OUT 3 but when the car is stopped at idle, the speedo needle still shows about 60mph. Its beginning to **** me off now, I cant warm my car up in the morning anymore since I wil put almost 40 miles on the odometer. What gives here.

 

check ur ground, make sure all three wires are grounded well. and make sure ur source is always hot and gives u a good 12 volts at all times.. if its just a little low it can give u problems, u also might wanna make sure the two wires coming from the speed sender are wrapped around each other. and are seperate from the power wire and the wire going to the VSS..

 

I have the 12v wire plugged into IGN. on the fuse block. Is there a port in the fuse panel that is hot at all times. Why would it have to be hot at all times?

 

Mine did the same thing at idle and I ended up grounding the dakota box itself. I used one of the screws on the box and ran a wire to ground. Not sure if it was the reason things work now, or I fixed something else when I was doing it.

Mark

 

hey BOTTLEDZr28 i just went though the same thing ur going though now, i spent hours tring to figure it out and this is what worked for me. use application #2 in the instructions and hook it up as follows, power wire from fuse box in heater blower fuse to the power on the sgi,( not hot at all times which is what u want) ground wire from sgi to a good ground source then splice into one of the 2 vss wires and make sure sig in is speed input signal and then u will have to use out 1 for the output signal. out 3 reads half of what it should and u will not get it set right, trust me i tried lol, so use out 1 and i have 3.73`s too and my dips were set as follows n,f,n,n,f,f,n,f,f,f and thats right on the $$ for me, hope that helps

 

lol great another way to use this damn stupid box. Billy, Ill give it a try when I get a chance. Thanks for your input.

 

LOL, yeah, all this trouble for a little box to fix an incorrect speedometer. Makes me feel safer living next to a big ole complicated nuke plant!