I have an 1986 Iroc-Z which had a cable driven VSS behind the instrumnet cluster. I installed a Dakota Digital Dash and the VSS which came with the dash.

This VSS went into the transmission a 700R4 and connects diredtly to the Dakota control box. The Dakota VSS is a 8000 ppm.

I have then connected the output cable from the Dakota control box to the brown wires behind the dash which go to the ECM and cruise control. This output is 2000 ppm.

The dash is set for km/hr. When I am driving and the vehicle hits 100 km/hr it cuts out until the speed is under 100 km/hr. Its like there is a speed limit on the car. The cruise control wont work either but did before the conversion.

Is the ECM getting false readings from the Dakota control box?
What did the old cable VSS send to the ECM? Was it pulses (2000ppm)?

Need help desperately.

 

Farmer, I thought the speedo was driven by 4000ppm and only cruise was 2000ppm.

 

AC, On the old setup the speedo was cable driven and a light sensor was on the rear of it and that fed into a VSS (a small yellow box on back of instrument cluster) and from there into 2 brown wire 1/ cruise control 2/ ECM.

 

What AC said, and the ECM gets 2000 ppm.

RBob.

 

RBob, The ECM and cruise are currently getting 2000 ppm from the Dakota control box. Could my problem be that the ECM expects the 2000 ppm for m/hr but its receiving 2000 ppm for km/hr (as the dash is set up for km/hr).

 

I'm going to buy a Vehicle Speed Sensor w/ Cable Drive from TPI which fits into the 700R4. I will connect the VSS wires to the Dakota control box (this will be 4000 ppm) and reconnect the cable to the original VSS which will feed the ECM and cruise (this will be 2000 ppm).

This will take me a couple of weeks as I have to import the part. I will post results.

 

im not certain, but the ECM in your car may well be speed limited which is normally around 100 MPH.
do you know if the Dakota box is ouputting the 2k signal in kph or mph? if it is kph that may be the problem with the motor shuting down at 100 kpm.
i think 100 kph is about 60~65 mph.
have you tried the cruise around 30~40 mph or 50~60 kph?
does the Dakota VSS use a gear to drive it?

 

It seems I may have fixed this problem by installing the Vehicle Speed Sensor w/ Cable Drive. The electronic wires with 4000 ppm to the Dakota control box and cable drive to original VSS with 2000 ppm to ECM. The problem obviously was one of reading km/hr as m/hr.

I'm now back to my serging and stalling whilst sitting at traffic lights.