What happens when the idle valve is open on an ECU?
In this condition, the idle valve is held all the way open to make the engine easier to start. So the idle effort will be 100% in this condition. Next, let’s consider what happens when the engine fires. After this happens, the ECU is in the running (as opposed to cranking) mode.
Why do idle RPMs go up and down?
The higher idle allows the engine to run while the air fuel mixture and timing are less than optimal. On the car with the idle that was going up and down, the ECU was likely trying to calibrate the inputs and output to get the idle where it needs to be.
How long does it take for an engine to idle from a cold start?
It controls the idle no matter what state the engine is in, hot or cold. Second, when the engine is cold, the computer is in open loop and goes to closed loop once the engine has met all of its presets. Can take up to two minutes on most modern fuel injected vehicles.
How to set up idle control on modular ECUs?
Copy the final idle effort into the table at each temperature cell as it is reached. Next, you should set up the idle-up for loads.
In this condition, the idle valve is held all the way open to make the engine easier to start. So the idle effort will be 100% in this condition. Next, let’s consider what happens when the engine fires. After this happens, the ECU is in the running (as opposed to cranking) mode.
Copy the final idle effort into the table at each temperature cell as it is reached. Next, you should set up the idle-up for loads.
Why is the idle valve open when the engine is on boost?
So if the idle valve remains open when the engine is on boost, air leaks back through the idle valve to the air filter and creates a boost leak. If you enable this setting, the idle valve will be closed when the engine is on boost (by closed we mean set to the minimum duty cycle). In a separate article, we’ll talk about closed loop idle control.
Why does my car idle when the engine is cold?
This only happens when the engine is absolutely cold (early mornings mostly when I haven’t been driving for at least 6-8 hours). There are no problems when the car is warm and I cannot tell any difference while driving (maybe less low end power but I might be imagining things).