Ignition Timing Help.

[quote:8f05789ce0="Turbo101"]I have a 1987 Toyota Celica ST,with 156,xxx miles.its a 2.0L 4-cylinder FE engine.

My problem is that i set my ignition timing to 15 degrees and using 87 octane fuel.im wandering if i advanced it to much?Should i adjust it back to 10 degrees or leave it at 15 because im getting better mileage?Will it pass smog on 15 or set it to 10 then get it smog,then adjust back to 15?

Comments will be appreciatable.THANKS.

Turbo101.[/quote:8f05789ce0]

Good idea reset it before smog testing-too much advance can cause detonation and raising the oxides of nitrogen and EGR being blame for something its not doing.

so should i leave it at 15 or adjust to 10 or 13?Which will be better?

Is 15 degrees putting detonation on my pistons??