I am trying to rewire my lt1/t56 pcm to use my speedo in my 92.

I can't find out were to tap into the wires on the thirdgen

what wires coming from the pcm I need to use?

I have the 32 pin pinout diagrams.

 

There should be either a tan/white or green wire that goes to the instrument cluster. That's where you connect to the speedo.

 

ok, so theres one green/white (according to pinouts) wire thats it? and i just hook it to the bulkhead vss wire?

thanks

 

ok i was looking over the thirdgen wiring and theres 2 wires that run to the dash of my thirdgen for the speedo. theres a wire in the bulkhead connector and theres a grey wire under the passengerside kick panel thet used to go to the old ecm that goes to the dash as well.

One is called VSS output 4000pmi to instrument cluster for speedometer.

The other says its vss vehicle speed sensor and its in the bulkhead connector and its purple.

which one do i hook to my lt1 pcm?

 

You want green/white one that is the 4000PPM output to the instrument cluster (will either been green/white or tan). That's the one you connect the drk green/white from the C220 connector (the white one) up to for the speedo.

 

ok, so the one that used to go to my old 730 ecm under the kickpanel needs to ge to the green/white c220.

Anyone know what the bulk head connector vss wire does?

 

No, the wire coming from the C220 connector needs to go to the wire marked 4000PPM output (I don't think that one goes to the old ECM, it usually went from the VSS buffer box to the speedo)

 

It would have gone to the E.C.M. or a VSS buffer depending on which engine was origanlly in the car. Since he said 7730 I am assumming it was TPI and it would of went to the computer. The purple wire in the bulkhead was one of the wires from the speed sensor. There is also a yellow wire in the bulkhead.

 

yea, the 730 ecm vss was built in. so, i guess i need the 4000ppm that went to the old cpu.

Thanks guys!