I wolly expect there to be no response, but one may dream!
In preparation of me shoving a Speeduino ECU into my SLK I’d really like to know if anyone knows how this valve works and is controlled.
While overviewing my plans on how I was going to put the Speeduino into the Benz, I was thinking of letting the OEM ECU control the bypass valve. However, then I remembered from previous episodes that literally any tampering with the crank VR signal at all causes the ECU to go into limp mode.
That means I’ll have to be control (I’m the captain now!).
I’ve been studying wiring diagrams and found some voltages ranges but those were mentioned to be for testing whether the flap works.
I am assuming that the valve itself is a stepper motor. Is that correct? Does it take a voltage signal from the ECU, or some sort of a control signal (PWM, direct stepper control)? I did find that pin 38 and 52 apply a 1.0 to 2.5v “motor signal” from the ECU. Would that mean that this voltage dictates the valve’s position?
I’m hoping that anyone actually knows how the valve works exactly, otherwise I’ll be taking my spare unit to the bench to reverse-engineer it. Possibly take it apart to wire a stepper motor controller directly to the stepper motor.
Another thing of note, the diagnostics manual did state that a voltage of 1 to 2.5v is applied when coolant temperature is above 70 degrees. I’ve always noticed that the car sounds much different when I first start it, till like 30 seconds of driving.
The supercharger whine is SUPER LOUD, until it spontaneously quiets down. I guess the valve is in the fully open position for a short while till engine is above 70c?
In preparation of me shoving a Speeduino ECU into my SLK I’d really like to know if anyone knows how this valve works and is controlled.
While overviewing my plans on how I was going to put the Speeduino into the Benz, I was thinking of letting the OEM ECU control the bypass valve. However, then I remembered from previous episodes that literally any tampering with the crank VR signal at all causes the ECU to go into limp mode.
That means I’ll have to be control (I’m the captain now!).
I’ve been studying wiring diagrams and found some voltages ranges but those were mentioned to be for testing whether the flap works.
I am assuming that the valve itself is a stepper motor. Is that correct? Does it take a voltage signal from the ECU, or some sort of a control signal (PWM, direct stepper control)? I did find that pin 38 and 52 apply a 1.0 to 2.5v “motor signal” from the ECU. Would that mean that this voltage dictates the valve’s position?
I’m hoping that anyone actually knows how the valve works exactly, otherwise I’ll be taking my spare unit to the bench to reverse-engineer it. Possibly take it apart to wire a stepper motor controller directly to the stepper motor.
Another thing of note, the diagnostics manual did state that a voltage of 1 to 2.5v is applied when coolant temperature is above 70 degrees. I’ve always noticed that the car sounds much different when I first start it, till like 30 seconds of driving.
The supercharger whine is SUPER LOUD, until it spontaneously quiets down. I guess the valve is in the fully open position for a short while till engine is above 70c?
