Which is the Timing Wire???
 

1992 K1500 Blazer 350 TBI

To set base timing I thought I was supposed to disconnect a tan wire somewhere. I open the hood and see a big wire loom coming up from the firewall from under the master cylinder and going over the back of the drivers side valve cover to the back of the intake manifold where wires branch out to the TBI, DIST, MAP, ETC. On the outside of this loom is a black wire coming from the fire wall under the master cylinder to a disconnect and from the other side of the disconnect is a purple wire going to the back of the manifold by the distributor. Is it the purprle wire that I am supposed to disconnect? On my last blazer there was a tan wire inder the carpet on the passenger side of my truck, i dont see that on this one.

look where the wires y out of the harness you should see a tan plug i know on third gens they are on the passanger side close to the heater box

On my 93 PU it was mounted to the plastic heater core cover towards the distributor.

yea it comes from the passside, its a tan plug that has a blck connector on that, usly ontop of the heater box, its the same as TPI witch i have.

than whats this purple wire for?

wheres the purple wire, is in the same place as the tan one should be, heres a simple test, start the car and listen to the way it runs, turn it off and then unplug that wire by the heaterbox, start the car back up and if its running diff and the RPMS are lower also that means you got it, and a camaro/firebird tbi is the same as the truck tpi and the harness i worked on both of best worlds.