Doug1

just got done racing the wife a little bit, she has a 2003 stock 350z, i beat her. any way, had some backfire through carb, i put in a new distributor last saturday and set the idle speed timing for 12. which direction should i experiment to eliminate the backfire. only on WOT did i have the issue. I got a 78 with a spartan 350 crate engine in it. edlebrock intake manifold, headers, rochester q-jet carb.

thanks

lars

The timing would have to be off by over 20 degrees before you'd get a backfire up through the carb. My papers outline timing setting in detail - just e-mail me for the timing papers. Setting initial to 12 doesn't mean much, and is no indication of what your total is.

The two common issues that will cause backfire up through the carb are lean mixture and valve train issues.

Lars
V8FastCars@msn.com

Doug1

hmmm... ok, i did mess with the two mixture screws also last weekend. i turned them in until it starting running bad, then turned out a half turn. i thought these only controlled mixture at idle? is that correct? thanks

Doug1

well i went ahead and fiddled with timing a tiny bit, set it closer to 14 and turned those two mixture screws out a half turn each. went for a spin, ran like a champ. thanks lars for responding and your advice.