Author Topic: Speed sensor input  (Read 6458 times)

Offline AVP

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Speed sensor input
« on: November 17, 2011, 08:22:44 pm »
Is there any way to get a different signal from the speed sensor on the audi S2/RS2 to supply that to VEMS so that vems can read the actual speed?

I have spoken to Marcell about this and sent a trigger log and it seems that there is an issue with the speed sensor sensitivity on the audi which makes it near impossible to get an accurate reading so that gear depended boost can be used.

I know that the original ECU can 'see' the speed for 2 features of the car and on both occasions takes that signal from the dash speedometer.

1) for the cruise control
2) for the diff lock release.

My question therefore is : is there anyway that i can get a signal to vems somehow to be able to read the speed without it being erratic?

Offline GintsK

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Re: Speed sensor input
« Reply #1 on: November 17, 2011, 09:30:08 pm »
Did you tried?: one of latest firmwares has changes regarding speed input.
Otherwise I think some low-pass filter may help. Means one capacitor at CPU input pin.

Offline AVP

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Re: Speed sensor input
« Reply #2 on: November 17, 2011, 09:37:37 pm »
i have tried with 1.1.95 version.

can you explain a bit more in regards to the capasitor? does this mean that the ECU needs to be opened? or can it be done in addition outside the ECU?

Offline GintsK

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Re: Speed sensor input
« Reply #3 on: November 17, 2011, 09:59:59 pm »
Inside. Cap between ground and CPU speed input pin. As a guess 10...100nF.