Awesome info! How did you wire it?
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'15 S3
'91 200 20v
'91 200 20v Avant -
I bought VEMS V3 current version for AAN engine which is plug and pray.....
You can get the pinout from VEMS and compare to pinout of Motronic AAN
Actual speed calculation is very important,
after you have done the speed calculation and input, drive and adjust "speed sensor cal"
Sample
Once correct info input is done, gear position is correct
PS for those who has only 5 gear, it will show 1-2-3-4-6 without 5
Last edited by kotnelson; 19 September 2013, 12:23.Comment
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Lots more great info but still missing one thing. The speed input. The factory motronic ecu doesn't have wheel speed being sent to it (my 3b doesn't anyway).
Where do I tap into the car for a signal to send to the vems? Is that signal just ready to input directly into the ecu? Or does a special circuit need the be built?
The speedometer signal I found in my 200 looks to be around 10v or so. Does this just get sent right into the ecu?'15 S3
'91 200 20v
'91 200 20v AvantComment
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on the AAN pnp ecus there is a 5v zener that caps the output from the stock speed sensor (which is a VR sensor so voltage does go well over 5v). it gets sent to the wheelspeed input on the vems, EC18, pin 8. you dont want to send more than 5v into the input.
more details here:
Marc Swanson
Proprietor, EFI Express
95.5 //S6 Avant
90' Coupe Quattro V8 4.2L twin turbo
93' //S4
83' UrQ
97' F250 7.3 diesel
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I don't want to loose the factory speedo either and looking at that diagram it seems as though it's re-wiring the factory sensor. The factory sensor also only uses two of the three pins.
Have you successfully wired the speedo into VEMS Marc? I have no problem assembling that little circuit, just want to make sure that's what I need to do.
I tapped into the speedo signal at the rear diff controller just to see what it was pulled up to. Stationary vehicle it's 10v. I spun the wheel by hand and it changed but didn't go over 10v. Could I assemble a voltage divider and input that?'15 S3
'91 200 20v
'91 200 20v AvantComment
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Ok, I think you are confused here.
The signal goes from the box to the speedo, the speedo buffers it, and then it goes from the speedo to other modules, such as the climate control, radio, cruise control and so on.
So what you want is splice the speedo output, not the wire that comes from the gearbox.
And Marc has a point with the zener - you need to shunt the excess voltage so you do not damage the ADC on the processor.Comment
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Yep, I'm certainty lost.
Looking at this diagram:
I am assuming AVR is the speedo sensor located in the transmission. Correct? If so, I don't want to be changing any wiring there that would render my factory speedo useless/incorrect. Not to mention, the factory sensor is only two pins, not 3...
This isn't a big deal, if I can't get it to work I am not loosing sleep over it. It looks as though even when implemented it's only "close". It'd be cool to play with gear dependent boost control, but again, it's not a necessity.'15 S3
'91 200 20v
'91 200 20v AvantComment
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I have nothing to do with this vems stuff...
But AVR is also a popular label for the Microcontrollers from Atmel.
RegardsComment
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On a side note Marc, do you have any experience with the newer firmwares in regards to vems reading this signal clearer after 1.1.95? My problem is that although vems sees the wheelspeed sensor, if you remember it jumps around and its making vems very erratic. After sending files to vems.hu of trigger logs they said they cannot do anything. It seems that some Audi's the sensor reads clearly and in some it doesn't. (Even though in my car the flywheel pin is an excact replica of the dual mass flywheel now in size and width.)Comment
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My apologize. that was engine speed.
Let me look into my AAN pin and will post up.
Motronic pin 50
3B = n/a
ABY= Vehicle Speed Signal
AAN= Instrument cluster (G21), Road Speed signal
G21 generate pulse signal, send to dash for speedo and multi+trip computor
Use this wheel speed input to EC18/8,
in my data sheet written "4k7 4k7 and 5v1 Zener protection diode"Last edited by kotnelson; 20 September 2013, 07:04.Comment
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