thanks Steve for the pointer. i wonder if the 75 speedo have the same calibration feature as the gtv6 speedo.

anyway, just realized my cheapo multimeter is dead after using it for 3 mths or so only damn...have to get a better one.

after half a year of waiting around, i finally got the chance to try and resolve the intermittent speedo problem again. i pulled new ground wires both to the amplifier and speedometer, pulled a new signal wire from the amplifier to the speedometer, and the problem persists. finally, after a tip from a friend that electrolytic capacitors tend to dry out after prolonged use, i replaced the only electrolytic capacitor in the amplifier (3.3uF, 63V, +-20% tolerance) and for a brief moment i thought i got it solved once and for all. the speedo jumped to life, hovering around 20mph when moving very slowly, and start to register true speed when car speeded up. but i noticed each time i changed gear, the speedo needle will drop too much before picking up again...then...once it reached 100kph for just a short time, it suddenly died again. kaput totally...zilch...stopped, checked the amplifier circuits, and detected no problems. i even replaced the electrolytic capacitor with a another one, and still it wouldn't work.

i'm really tired and pissed. i just can't believe how a simple speedo device can be such a pain in the arse in the 75. i think i would have no choice now but to get the dakota SGI-5...sigh...unless the speedo unit now is blown (i hope not!).

I installed a Dakota box (According to "Steve R"s instructions) to my 75TS gearbox (3wire) and GTV6 speedometer (2wire), did not use the orig 75TS amplifier.

The instruction from "Steve R" was very good but on my car the 3 wires from the sender was different colours (Surprised!? ). My wires was:

Pink: 12v ...... Yellow: Signal ...... "No Cable Insulation": Ground
(It worked that way when I only used the orig.amplifier box anyway... the speedo read about x2 though..)


Now to the Problem:

As soon as the engine starts and the tachometer jumps up to around 1500rpm the speedo does the same and lays the needle at 40 km/h. If I rev the engine the speedo follows the tacho.

In the Dakota "Trouble shooting guide" they list 3 things that can cause my problem:

Speedometer will read when the vehicle is sitting still

Possible cause 1: Tach wire too close to speed signal wire
Solution: Route the speed signal and tachometer wires away fram eachother to aviod interference.
Done: Routed a new wire from the Dakota box to the speedo
Result: Nothing. Speedo still follows tacho

Possible cause 2: Signal IN and OUT routed to close
Solution: Route signal IN and OUT away from eachother to avoid feedback
Done: (Hard because the Input and OUT1 slot sits directly beside each other.) Tried using more shielded cables. Tested using OUT3 (Also AC as OUT1)
Result: Nothing. Speedo still follows tacho

Possible cause 3: Ground interference
Solution: Make sure the speed sensor and SGI-5 are grounded together.
Done: Checked grounding with multimeter, was ok.
Result: Nothing. Speedo still follows tacho



PLEASE HELP!! What can I do??

Now I have got the Dakota working.

It worked when I took power directly from the battery.

To keep the box from being ON all the time I installed a relay and used the 12v from speedo as "guiding power".

Don't know why but now it works anyway

some input here would be VERY helpfull

ive got my sgi5 in hand...but the 3 wire off the TS box is yellow brown and "unshielded"(obviously ground)

yellow is on 1 end with the brownish color in the middle....need to know what wire is what

if it helps ive got a jaeger box sitting here as well as a guide ...the unshielded stays unshielded all the way into the jaeger..the yellow wire switches into a red wire and the brown wire switches to a white wire..where the jaeger plugs into the sensor

the 2 wires of my speedo match everything else stated

anyone????

like to get this up and done...wanting to goto the beach this week and waiting on the speedo