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Setting Base Ignition Timing on 4.3L V6

11-26-2003, 09:36 PM
I recently purchased a 2WD 1991 S10 with a "Z" code 4.3L V6 TBI engine & a 4 speed automatic transmission. I am trying to set the base ignition timing on this engine but the emission tag that contains the timing setting & the procedure on how to set it has deteriorated with age & is unreadable. Currently I have set the timing to 12 degrees BTC with the engine warmed up to operating temperature & idling with the transmission out of gear. I was unable to verify the engine's idling speed due to the fact that I do not know where to connect a tachometer in the ignition circuit. Any info someone could provide about the emission tag would be greatly appreciated as none of the local chevy dealers could shed any light on the situation. This vehicle is federal emissions standards not California.

11-26-2003, 10:46 PM
I believe the correct base timing for your 4.3 is 0 with timing wire disconnected. wire is located under pass.side dash. you may have to put the carpet back a little to find it. i want to say its tan in color.

11-30-2003, 09:00 AM
Based on my 93 4.3 "W" engine, the above info is correct. The color of the wire is Tan with a black tracer. It is under the carpet under your left big toe on the pass side. Sounds like you could have too much advanced dialed in!

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