MicroSquirt.com read only forum (Jan.15,2018)

Looking for help to identify Audi (VW) throttle body i bought ages ago. Diameter is ~70mm (2,75") and it has a something built-in. I'm guessing it's stepper motor for idle adjustment, but looking for confirmation of that and/or exact info of wiring.
It has following part numbers stamped:
078 133 063 AM
408.237/221/007 I 5 35 98



Petteri

That contraption looks a lot like the throttle body I purchased first, which was from a Catera. If you operate the butterfly manually, you may hear some gears turning. If you can take the large black cap off the end you may see gears as well as a board with some resistive traces and the associated wipers. In other words, I am not sure how you are going to use this TB, unfortunately. Mine is also on the shelf. Operating these has been discussed on this board, but the consensus I think has been that the control algorithms are really too complex, and more so than you would think. The motor and gearing on the one I have were for the full range of operation, not just idle.

On second look, it appears that your TB may have a way to connect a throttle cable. If so, you may need to disable the idle control (remove gearing if present) and go with an external bypass.

Quite a few VWs with Bosch injection used a DC motor run in a bridge arrangement so it could turn both ways . The motor is connected to the
throttle shaft in a mechanical fashion that allows the motor to finetune the idle opening angle , so as to control idle speed . At above idle manual opening of the throttle the circuit is deactivated by the ECU .
In the same contraption also a double TPS could be integrated that serves as load input to the CPU .

For BOSCH single injector set ups ( mono-Jetronic) the idle motor and TPS were separate units , for some more modern multipoint units it was all one box as in your picture .

I like the BOSCH DC motor idle control idea , but not sure if there are any HW and SW adaptions in MS or MSnS Extra to run it .

Heribert

I dont see a seperate actuator for cruise control. That stepper motor might control the cruise if it has full range. Though I dont know Audi that well.

I have a same kind of TB from a 2.0 VW Passat (Simos). I was planning to make the idle stabilizer work, but have other plans for my VW engine now.

In the other hand I have a Bosch Mono-motronic in my Suzuki SJ. As mentioned there is also a DC motor for idle. I did a test circuit with a PIC-controller using H-bridge to drive it. I'm planning to connect it to the MS fidle output. It reads the CLT and TPS and has a map of different temperatures and tb angles. The idea is that when MS signals idle the pic will move the tb plate to the right angle using the DC motor. When the idle signal goes off the motor resets to zero value.

At this point I'm not using the TPS in MS because there are two of them. So because the pic will need at least the lower one I decided to connect both and make a DAC output (r2r network) for the MS to use them as one linear TPS.

If this setup works i will post it somewhere for others to enjoy...