The title pretty much says it all. The car is running super rich at idle and the car wants to die with electrical load. TPS has been tuned and the idle is at about 1200. Emission have been removed as well but the BAC valve is still in use. I keep fouling plugs every 300 miles (only roughly 700 on rebuild) The car runs great when not at idle with no hesitation at all and a consistent sweeping rpm. Check out my build thread for more details on the engine.

Occasionally I do get a mid 13:1 ratio at idle. I know larger streetported engines will run rich, but the fouling of the plugs has me concerned. Also the engine floods when warm started, but the fuel pump switch helps with that and the injectors have been rebuilt and flow tested.

 

I see nothing saying you've upgraded to an appropriate alternator, nor checked output voltage, specifically at load. The s4 alternator can barely run a stock car, let alone one with a decent fan.

 

That was my first thought and I'm in the process of sourcing one out. The fuel issue is my main concern at this point. The alternator will be upgraded within the next week or so. I already can tell the alternator has seen better days, when running the stereo before the rebuild I would have issues.

 

It has little to do with the alternator.

How are you controlling fuel?

12:1 AFRs are way too rich and will cause the idle to be very weak. Any sort of load will drop the idle as it drowns in fuel. At those rich AFRs, the BAC valve won't have very much effect on compensating for electrical loads.

You need to decrease the amount of fuel at idle. Should be in the 13s.