Audi 20vt TPS

smolly · Post by **smolly** » Thu Jan 18, 2007 1:10 pm

At the moment I am figuring out what OEM sensors I can re-use from Audi/VW.
And (sofar) the TPS seems to be the only mystery. It has 7 pins, too many combinations to try.
Who can tell me the pin description for this throttle body:

Thx,
Roger

smolly · Post by **smolly** » Sun Jan 21, 2007 3:34 am

I have done some measurements with the following outcome:
1. actuator + (idle) ?
2. actuator - (idle) ?
3. closed = pin 7 / open = ∞
4. GND ?
5. TPS ? (0,6V closed / 4,3V full)
6. not connected
7. +5V ?
8. ?

Can someone pls. confirm!

smolly · Post by **smolly** » Mon Jan 29, 2007 1:46 am

For the next one who wants to use this throttle body,
the pinout is correct and working fine after calibration in Megatune.

thx for the responses

16vboost · Post by **16vboost** » Tue Apr 03, 2007 8:21 pm

Thank you for providing this information. I am considring using a similar vw throttle body on my 16v Scirocco. How much does the throttle plate open when you apply 12v to pins 1 and 2? do you think that the opening is proportional to the current applied? AKA PWM Idle control? I'd like to do some poking around with one of these TB"s but the local junk yard want's $125 for one. I think I'll check ebay first. Thanks again for your contribution.

smolly · Post by **smolly** » Tue Apr 03, 2007 9:32 pm

It opens about 5-10 degrees, I haven't got the engine running yet, so I am also curious what it would mean in rpms.
I also had the same idea about PWM, but left it behind me. I do not see the real purpose for it on my car. However I think it will work, Audi/VW is using it like this I would say.

smolly · Post by **smolly** » Thu Nov 22, 2007 12:25 pm

Pin 1 & 2 are for the idle control, but how can MS control this?

smolly · Post by **smolly** » Fri Nov 23, 2007 11:27 am

I found this schema of the TB. Is this a stepper motor?

vinister · Post by **vinister** » Fri Nov 23, 2007 7:20 pm

Isn't that a drive-by-wire throttle body?

Looks similar to the one that came on my vw engine. I swapped it for an earlier cable type.

smolly · Post by **smolly** » Sat Nov 24, 2007 12:37 am

vinister wrote:Isn't that a drive-by-wire throttle body?

No, its a cable TB and there is no idle control anywhere else on the engine.
That's why I expect that audi/vw is using the "motor" in the TB. But how?

smolly · Post by **smolly** » Sun Nov 25, 2007 4:35 am

Thx

So pwm with a frequency between 20-30 kHz. MS1 does not get higher then 10kHz, but it is worth a try.

smolly · Post by **smolly** » Sun Dec 16, 2007 5:19 am

Unfortunately these high PWM frequencies are not possible (with MS1 at least, I don't know for MS2).
The exact frequency is also a bit unclear, the window states 10000/x and the help screen (F1) states 1000/x.
But I noticed that with these low frequencies it is very hard to control the valve.
33% idleDC = 10% TP = ~2200 rpm
32% idleDC = 5% TP = ~1450 rpm

If I understand correctly:
The higher the frequency the less steps remain for control of the DC. With a value of 100 for Idle valve frequency "x" there are only 10 DC steps, 50 only 5, etc.

Question:
Is it possible to set a fixed DC between 0 and 40 degrees, instead of a lineary decrease with an increase of the CLT? so that the idleDC is x% till 40 degrees and 0% when higher CLT temps are reached.

Post by **efahl** » Sun Dec 16, 2007 6:01 am

smolly wrote:If I understand correctly:
The higher the frequency the less steps remain for control of the DC. With a value of 100 for Idle valve frequency "x" there are only 10 DC steps, 50 only 5, etc.

That is exactly how it works. You have a fixed clock, and you break up the discrete ticks into groups to approximate duty cycle. Assume, for example, a clock with 1000 ticks per second. You could run a 10 Hz PWM that would then have 100 ticks per cycle and a single tick would get you 1%, which defines the resolution of the duty cycle (1 tick "on" means 1% duty cycle, 2 ticks is 2% and so forth).

Now if you use that same clock for 20 Hz, you only have 50 ticks per cycle and hence 1 tick is 2%, 2 ticks is 4% and your duty cycle resolution is thus 2%. Going to 40 Hz, you have 25 ticks per cycle and things get even worse...

smolly · Post by **smolly** » Thu Dec 27, 2007 12:03 pm

Thx sofar, however question remains:
Is it possible to set a fixed DC between 0 and 40 degrees, instead of a lineary decrease with an increase of the CLT? so that the idleDC is x% till 40 degrees and 0% when higher CLT temps are reached.

smolly · Post by **smolly** » Sun Jan 06, 2008 9:27 am

FIdle question continued in seperate topic:
viewtopic.php?p=187261#187261