vems speed sensor Hz

[a4kquattro]

Exactly why I ask

The help menu and vems documentation is a little confusing about how to set it up.

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:

http://www.vems.hu/wiki/index.php?page=InputTrigger%2FWheelSpeed

[amd is the best]

Yes. No idea if VEMS will be happy with that - be careful what you wire into which inputs as you can easily fry stuff if you do it wrong.

Exactly why I ask

The help menu and vems documentation is a little confusing about how to set it up.

[prj]

The speedometer signal I found in my 200 looks to be around 10v or so. Does this just get sent right into the ecu?

Yes. No idea if VEMS will be happy with that - be careful what you wire into which inputs as you can easily fry stuff if you do it wrong.

[amd is the best]

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?

[kotnelson]

Awesome info! How did you wire it?

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

[amd is the best]

Awesome info! How did you wire it?

[kotnelson]

This is what I used and with GPS was very close at 100 km/hrs








Calculate actual speed from Gear ratio / Tire Size / my tranny is AXM
Vehicle speed (KM/H) = n/iov*UA*0.06
n=Engine Speed (RPM)
iov=overall ratio (iG*iA)
iG=Gear ratio (Driven/Drive)
iA=Final (Axel) ratio (Driven/Drive)
UA=Dynamic rolling circumferences of tire 2*(22/7)*r








Road speed from the log was OK

[A80Avant]

I don't think so. Its hit and miss on our cars. At least that is what I have been told. Perhaps easier if you go to 60-2 trigger

[amd is the best]

Any updates on this? I'd love to add wheel speed to my 200 and have gear dependent boost control.

[KRIENG]

Can Urs4 use speed sensor ? (1.1.96)
when I take Log Wheel speed change a little

I try set First Speed = 50 Hz/100kph, divider = 1 is it correct ?

What is Second Speed Hz ? should be same as First Speed

[A80Avant]

as i mentioned. no solution at the moment. i have spoken to Marcell who says that the best numbers to use is 112 and then anything between 4-7ms but i have tried many values between and it doesnt work as expected. So nothing to do now but wait.

[th.b.w.]

Have set 220 Hz, rising and it is close to the tacho.

But when i accelerate it turns 10-20 km/h down and 5 up....

This is not stable and the gear shows sometimes from 3. to 4. and so.....

Any solutions ?

Thomas

[th.b.w.]

Hi,

Car is running since 10 day's, but only 150km of driving....
Some working with idle (1.1.64 to 1.1.81), but now stabile.

I have a quetsion:
Knows someone who can i connect the speessensor signal in the 3b engine ?

S2Central.net told me go to pin 6.
I wondered that there isn't an speedsensor input on pin 6.....
It is Inj. E ?!

In the wire diagramm (S2/3b/till sept.1991) it seems that the speedsensor input is only go to autocheck....


Thanks Thomas

[A80Avant]

Other users confirmed that the speed sensor is erratic. Marc is going to be testing it as well, but Marcel will hopefully try and update it on a later firmware. its a pity that it seems so difficult to correctly adjust this sensor, as it would give fantastic results if we are to use gear depended boost.

[A80Avant]

Right, here are the results of my tests today.

anything between 112-114hz works and it is pretty close to the GPS wheel speed.

Problem is that whenever the car accelerates (mostly) the gauge needle on the wheel speedometer jumps up then down before it settles to the proper speed. If speed is maintained for a few moments, then it is ok.

I tried different minimum period times as well as both and rising edge and didnt have any good effect. most of the times it was better with period time close to 400-1600us.