DBW TPS location

Hi,

I have a 4 cyl BMW motor with ITBs and want to add a DBW actuator. Now I understand that the Efi technologies unit is a re-cased BOSCH DBW throttle body which has inbuilt 2 TPS sensors. I already have a TPS sensor on the throttle shaft of the ITBs. Can I use this TPS and just one of the integral TPS sensors in the bosch unit?

I was thinking it might be nice to know that when the actuator moves it also moves the actual shaft of the ITBs?

This sounds like a perfect opportunity to actually have a redundant DBW system with some inbuilt fault identification, provided you can actually do the logic in the ecu.

You may find the ecu wants to see the two opposing signals from the DBW driver as they track together, opposed, depending on how flexible the setup is.

Hi, I would highly recommend against doing this. The Throttle Servo Position sensors are used for error checking of the movement of the actuator, and if they vary from each other, the DBW system will go into fault. (in a properly configured system) Having one sensor on the motor, and another on the shaft causes all sorts of issues in operation, with the shaft signal usually not tracking 1:1 with the motor, as well as being noisy in most cases that i have seen this. You will also have stiction and flex in the linkages that will add a further delay to the movement of the sensor on the shaft.

The ECU is controlling the motor, what happens after that is not considered, you could log the position of the shaft using another input, but do not use it as part of the control strategy.

Thanks for your help... I see why now this would be a bad idea given how close the dbw inbuilt tps sensors need to be to follow each other so closely.

What I thought would be a good idea was that if the dbw tps sensors said the throttle was closed and the one on the itb shaft read as open it would activate cuts to prevent the chance of WOT runaway...