[Supra Bob]

This is gonna sound like a smart ass question, but I am being serious. I know I tend to miss some of the seemingly inconsiquential details when I become so involved in the major ones that over look simple stuff...

Does the check engine light work?

I once spent $700 trying to fix my charging system... over a broken 35 cent fuse....

 

[Supra Bob]

Open loop and closed loop refer to fuel delivery maps.

In closed loop mode, the ecu monitors all the sensors(o2 sensor, tps, AFM, engine temp and a couple of other), and adjusts the amount of fuel delivered to the intake according to the real time readings of these sensors.

Open loop is a condition that the motor basically ignores all these sensors and relies only on a pre-programed map. Usually, open loop is only used at Wide Open Throttle (reffered to as WOT), and is activated when the Throttle Position Sensor (TPS) senses that you have pushed the gas pedal to or passed the point that it requires to activate it.

For more info, I recommend you pick up a book called "Bosch Fuel Injection" by Charles Probst SAE. Great book that contains more info on fuel injection than the average person could ever need to know