You don't/cant change the IAC. The IAC is a physical device that moves to to adjust airflow into the engine based on the base running airflow table and trim boundaries to try and meet the desired idle rpm. PCM uses 3 ways to achieve the rpm; spark timing, airflow (iac), and fuel ratio. Spark is the fastest, followed by airflow, and fuel.

 

So if that is the case, shouldn't the IAC be adjusting properly? When we told it to open slightly more with the verus, the truck started and ran perfectly. When we matched the desired idle speed with the setting on the IAC, it also started and ran perfectly, but at the lower RPM. also while doing both of those tests, we noticed the lack of raw fuel smell from the exhaust. The way its tuned now, it will make your eyes burn at idle, when it will idle.

I am taking it to another guy that has HP tuners, and he is going to see if he can pull the file for me, and email it to me. If he can do that, Ill post it here so you guys can take a look and tell me what needs to be changed. In a few weeks, I will be buying me own HP tuners setup. I hate relying on others to get this stuff done locally, when I know full well, with some research, and patience, I can do this myself.

 

Doesn't your truck have a cable throttlebody? Does it have a idle air adjustment screw?

 

It is a drive by cable, is that adjusting screw used to set idle? Or blade position? I don't want to adjust the blade and have it idle higher just to get it to start easier.

 

The blade sets the lowest possible position. Its the job of the IAC valve to provide additional airflow at idle based on what the computer is requesting to maintain the requested idle speed. The ONLY time you should adjust the set screw is if the IAC valve, when fully open, is not able to provide adequate airflow. If you adjust the set screw, you will need to retune the idle airflow tables as they will be different now.

 

More or less what I was thinking. I dont want to mess with it. Mostly because this engine started and ran perfect before the swap. I really need to get some one on it with HP tuners that knows what the hell they are doing.

I appreciate the help in here!