the timing on vortec engines is automatically set by the computer. there is no magic wire that has to be disconnected as the 87-95 trucks have. you will most likely need a scanner to tell the computer what to do.
when ever removing a distributer cap I always use a paint marker or sharpie to mark where the rotor was pointing when I pulled it out. this ensures you will be rite on the money after dropping new one in. Also if you put a mark on the cap and the base of the distributor. your will be again at exact timing mark.
I need an answer on this question also. I marked the distributor but somehow they got screwed up in the process. The question is: How to re-install that distributor and set the timing on a 97 Suburban 5.7 vortec engine. The book says to disconnect the Electronic spark connector which I can't find. The Haynes manual is tooooo general and doesn't address my situation.
Out of Time in Pooler Georgia
The wire they are referring to is usually hidden up on the firewall (engine side) behind a removable cover. It will likely be sort of purple shade depending on year and the connector is a long thin snap-apart plastic piece about2 - 2 1/2 in in length. When you disconnect this, it prevents the computer from counteracting (electronically) the physical change in timing as you rotate the distributor. This allows you to use a timing light to set the base timing as per spec. After you are done, reconnect the wire and the computer overide is back in place. You will likely get a check engine light because you had the engine running in order to do timing set, while the wire was disconnected. Disconnect the battery for about 30 seconds, reconnect and let the computer go thru its "learn mode" to reset all the various internal values.
Regards, Vic M.
If you can't find the connector with the tan wire and black stripe...... It may not have one. Somewhere between 1996-1997 the timing was changed to be set through the computer. A scan tool is needed to read the timing. Stan
The tan and black wire should be connected to your distributor if its not there check your behind your glove compartment. Kory