I have a 90 rs with a full roller 355/T5 no ecm, my speedo does not work.
I read somewhere on here that you can fix this by connecting certain wires together to complete the circuit .

If anyone knows what I am talking about or has any info on this please chime in.

I do not wanna use the ecm, it has an MSD 6AL box in it. ECM isn't needed to run the car.

Thanks ahead for any info.

 

If the car was TPI then the speedo signal from the VSS went to the ECM 1st , then the speedo.

You most likely are going to need something like a Dakota SGI-5 to drive the stock speedo

http://www.dakotadigital.com/index.c...rod/prd126.htm

See
https://www.thirdgen.org/forums/post...298-post3.html
https://www.thirdgen.org/forums/elec...l-sgi-5-a.html

 

Thanks, The car was equipped with a 3.1 liter 700r4.

 

Re: Dakota Digital SGI-5


With the V6 there is no buffer box, the V6 cars and TPI cars used the same chassis harness and wire routing.

The VSS input goes to the ECM, then the ecm OUTPUTS the signal to the cluster and cruise box.

The connections are :

Pin B9 of the C1 Black ECM connector: Purple VSS Ground
Pin B10 of C1 Black ECM connector: Yellow VSS Signal Input
Pin B11 of C1 Black ECM connector: Gray Vehicle Speed Output 4000 PPM
Pin C1 of of the C2 Black ECM connector: Red Vehicle speed output 2000 PPM

The purple and yellow wires run from the vss inside the harness through the passenger fender, and then into the car at the kick panel, then into the ECM.

The ECM then outputs the 4000 PPM signal for the speedometer through the gray wire which connects to the chassis side of things at the C207 under dash connector terminal "D"

The ECM also outputs the 2000 PPM signal for the cruise control through the red wire and connects to the chassis at the C207 terminal "P"


If you are just trying to correct a gearing issue, then you need to cut the Yellow VSS wire before it hits the ECM and connect the vss side to the SGI5 Input, then the other side of it to the SGI5 Output.

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Thanks for the info, I reposted it so I wont lose it