Have an 86 IROC dropped an 89 tpi engine with LT1 cam less the tpi put a performer intake with a proffesionaly rebuilt quadrajet. Has a vaccum advance MSD carb on it can not get to open seconderies. Electric choke works fine no vaccum leaks sprayed starter fluid around it got no response. Guy guranteed it for 5 years, told me to take it back to him just dont want to be taking it off an on if I can fix the problem. Once again the problem is secondaries will not open. Pulled vaccum off the secondarie pull off still no secondaries locked the secondary lock tab (I think its that) and get a backfire. I need your help guys Thanks

 

have you tried adjusting the secondary spring tension?
http://www.hotrodders.com/forum/adju...jet-98917.html

 

If you're sitting in the driveway with the hood open and air cleaner off, blipping the throttle and expecting the secondary air valves to open, you're barking up the wrong tree. It ain't gonna happen.

Adjust them per the E4ME sticky in the top section of this forum, or the tech article linked from the thirdgen.org homepage.