[rfmaster]

Originally Posted by glock35ipsc

Jamie, rfmaster, or anyone else......

I am in the middle of a 5.3L Vortec install in my 85, which prior to this had been converted to TBI with parts from a donor 87.

I am trying to find the wire that runs from the firewall to the pumps, the wire that actually powers the fuel pumps. Is it the tan/white wire that comes from the relay that powers the pumps? What about power for the tank selector switch, is it from the same wire?

I have a signal wire that comes from the 5.3's PCM that will turn on a relay. I just need to find the wire that goes to run the pumps now.

If TBI conversion followed factory layout look for BOSCH style fuel pump relay on the firewall. The tan-white or sometimes gray wire is a switched side of the FP relay. That wire should be 12 or 10 AWG - large diameter wire since any voltage drop results in reduced FP fuel pressure.

The tank switch should be a completely different circuit - I do not have this information handy at this time

//RF