just curious, what is the purpose for the coolant lines on the bac valve on the side of th upper intake manifold.

 

the BAC controls idle. The coolant goes from the block to the cold start valve to the bac then returns to the t stat neck by the temp sendor. The BAC is not worth removing IMO, but the cold start is what tends to flood the motor if it is cold and started, then turned off BEFORE the car is up to operating temps. The BAC compensates for acc. load such as AC and PS. As the Acc puts a load on the motor the BAC will bump up the idle so the motor will not die.

 

The coolant lines regulate the BAC temperature. They both cool the coil and warm the solenoid when cold.