here goes, i bought a 90 iroc 305 tpi 5 speed from a lien sale, it has aftermarket heads, rocker arms, big mouth intake, tpis throttle body, pretty lumpy cam. it starts and runs pretty rich, smoking some from unburnt gas. it sets a code 43 about 5 seconds after starting and you hav to play with the throttle to keep it running. it has msd 6a box that is unhooked in the fender well and a msd coil hooked up to the distributor running off the factory ignition now. replaced knock sensor, no change. don't know what cam is in it but it sounds pretty big. these parts are not new, you can tell it was run with these parts for awhile due to discoloration and such. if anyone can help i appreciate it. the car sounds mean when you rev it up, it just has to be fixed to pass smog and i want it to be right. thanks

 

one other thing, when i tried to check and set the timing, there is a red paint pen on the balancer, but i can't find a groove from the factory to set it by. when using the timing light the red mark is over at about the 11 oclock position instead of the roughly 2 oclock position of the poiter on timing cover. trying to turn the distributor brought it over to the 12 oclock position and it runs bettter than it did at first but won't get anywhere near the pointer. so now the timing is basically set by ear and where the car feels best cause i can't get it to read right, and i did unhook the wire on passenger side before checking and setinmg it thanks

 

Sometimes these after market cams don't do well with the stock speed density computer. Can you get an intake manifold vacuum reading? Sometimes a cam with too much overlap will give you too low intake vacuum at idle, sending your computer into a frenzy. Stock vacuum readings I think are somewhere between 17 and 22 in Hg.

 

Back in the day, ya could pull out the choke. make engine idle rich, with a nice lope. Wash the cylinders with gas, but it sounded cool.

A too rich idle, will be lopier, then a lean one.

Bigger cams can make for rich or poor idle. They mess with the o2 and vacuum. Headers can make for a cold o2, send you back into open loop.

Do a search in TGO, on "big cam" or "how to fix" include the quotes.