converting 5.7 tbi to 5.7 tpi

[kremersauto]

hello i have a 1987 chevy r10 silverado with a 5.7 tbi in it and id like to put the 5.7 tpi in it i got out of an 88 formula firebird. i have the complete engine and transmission and computer and wiring harness. i have already installed the 700r4 from the firebird into the truck. i got a gauge cluster from a 91 suburban with the electronic speedo. im trying to figure out what to run the wires from the speed sensor on the tranny to the wires are yellow and purple. i also have the yellow buffer box from the firebird. im just starting on trying to get the speedo and gauges working correctly before i pull the motor to swap it. any help would be appriciated.

[Mickeymotormount]

Generally, the speed sensor wires go to the PCM(computer). The PCM processes that info and then sends a signal to the speedo on a separate wire. If the Firebird speedo is electrically operated, which I believe it would be since you have VSS wires from the trans, you have to use the wire that originally fed the speedo on the Bird to the new speedo. You will probably still need the buffer box to get the right signal to the new speedo.

A wiring diagram of the Firebird would be helpful since most of the stuff you have is from that car.

Try this site:
http://search.ebscohost.com/login.as...ile=autorefctr
User name: student
Password: watc

If you prefer, here's one on CD. Others are available but somewhat pricey.

http://www.ebay.com/itm/1988-Pontiac...661549&vxp=mtr

[MrHorsepowerLSx]

Generally, the speed sensor wires go to the PCM(computer). The PCM processes that info and then sends a signal to the speedo on a separate wire. If the Firebird speedo is electrically operated, which I believe it would be since you have VSS wires from the trans, you have to use the wire that originally fed the speedo on the Bird to the new speedo. You will probably still need the buffer box to get the right signal to the new speedo.

A wiring diagram of the Firebird would be helpful since most of the stuff you have is from that car.

Try this site:
http://search.ebscohost.com/login.as...ile=autorefctr
User name: student
Password: watc

If you prefer, here's one on CD. Others are available but somewhat pricey.

http://www.ebay.com/itm/1988-Pontiac...661549&vxp=mtr

Why don't you just swap over the PCM and TPI harness and leave your mechanical speedo in place