At what point does the system go into closed loop? Reason I ask is because my system is not going into closed loop. The engine runs for about 5 minutes and stays in open loop. Normally when in closed loop, the A/F gauge jumps back and forth from rich to lean but ever since my TBI to TPI swap the gauge reads 14.7/1. Does the coolant temperature have to reach a certain point before closed loop operation? Thanks.

 

There are many variables in the chip that allow your car to enter closed loop. In my chip I have to wait 300s, coolant temp has to reach 75 degrees and the oxygen sensor has to heat up to a certain temp. When all of these conditions are met your car will enter closed loop.

If you have headers and have moved your 02 down the pipe it will take longer for it to warm up and also it will take a long time when your car is idling..

If you need more info just visit the DIY Prom board..