Speedometer question (Page 1/1) LongEZ RC FEB 13, 10:24 PM Trying to figure out why my speedometer doesn't work.1988 Fiero GT Getrag 5 speed. 4.9 Caddy carburated and single wire HEI distributor. for this to work does it need the origional ECU? It appears to be wired but I just got this car and it is kind of crude on the wiring in the engine compartment. Patrick FEB 13, 11:56 PM Is the Vehicle Speed Sensor connected on the transmission?