View Full Version : inconsistant 7562 (graphs included)

06-04-2007, 11:46 AM
I think it's in the PID tuning, but even when the boost is less than desired I'm getting PWM.
Here's one pass, and at the top of high gear it started to pull a little boost. I would call this GREAT control.

Here's another pass without making any significant changes to the box (no changes to any parameters) and the control was way off and the PWM didn't appear to have the same effect as the first graph.

Any thoughts?

06-28-2007, 01:51 PM

The PWM will always show some movement or operation no matter what the boost numbers show. The first picture posted the pwm has a steady swinging up and down and never bottoms out (top or bottom) indicating constant control. In your second picture if you notice the PWM flat lines a number of times at 40 which means the valves were closed trying to force the unit to build boost but for some reason the waste gate is not staying closed. Basically meaning that the unit is controlling as it should be but the waste gate is still opening for some reason. Something has changed to cause this issue.


MSD tech4