E30 obd2 vss

[alndks]

I gave signal from the Brown/red speed input in the cluster.
Then I gave signal from green plug behind cluster where the cruise control get speed signal.
Then I gave signal from the pin 14 in c101.
The result from all is the same.
They all give very low speed to dme
And according to this manual :

http://wedophones.com/Manuals/BMW/1996%20BMW%20318is-c%20-%20320i%20-%20325i-c%20-%20328i-c%20%20Electrical%20Troubleshooting%20Manual.pdf

The speed signal is dme pin 15 speed signal right rear to abs/asc control module not instrument cluster
This is us manual. Not euro

[nando]

Yes, but as I said, it goes through the ABS computer first where it gets processed down. the ABS sensor doesn't go straight to the DME, it's just that the ABS VSS output is based on that particular wheel sensor.

[328ijunkie]

After investigating/testing on my OBD2 car here.. Youre right. For 0-60mph (wheel speed) i get 0-~126hz at pin 14. This means the ECU is seeing:
126hz for a 9tooth wheel spinning 60mph
vs the ~671 its looking for.

Ive never had a car code on me though or I possibly would have noticed this... hrm. How to remedy? I shall investigate.

[evandael]

so could this be remedied by running an additional abs sensor and inputting that to the DME?

[nando]

No, the ABS sensor outputs a sine wave, you need a square wave.

[evandael]

hrmmm. i haven't the slightest of electrical knowledge.

another different sensor? what about a hall-effect run off the 48-tooth ABS ring (would it not be the right application of that type of sensor?)

[alndks]

Yes, but as I said, it goes through the ABS computer first where it gets processed down. the ABS sensor doesn't go straight to the DME, it's just that the ABS VSS output is based on that particular wheel sensor.

On e36 goes directly tfrom abs/dsc module to dme.
Never said it goes directly from abs sensor on e36.
I try on e30 abs sensor to see the result and no signal because its a sine wave
But on e36 the signal is between abs/dsc to dme asccording to manual, the cluster has nothing to do with the vss signal to dme.

[alndks]

After investigating/testing on my OBD2 car here.. Youre right. For 0-60mph (wheel speed) i get 0-~126hz at pin 14. This means the ECU is seeing:
126hz for a 9tooth wheel spinning 60mph
vs the ~671 its looking for.

Ive never had a car code on me though or I possibly would have noticed this... hrm. How to remedy? I shall investigate.

If you go too slow for a while (under 4-3km/h like traffic) the dme gets 0 speed signal and it will have a code. Maybe not cel but if you check with obd diagnostic you will the the vss code stored
Yes the dme looking signal ~671 and getting 126hz
671hz/126hz=5.325.
We need to boost the signal 5.333 time up to be correctly.

[luckysnafu]

I confirmed on my way home last night that boosting the OBD speed signal in Torque by 5.33333 will give you the correct speed.

So now I'm confused. Is the e36 ECU getting the correct speed signal from the e30? And if it's not, does this have any negative affects on anything?

[alndks]

The e36 ECU does not get the correct speed from the e30 cluster.
I do not now how effect the perfomance of the motor.
If the dme sees the speed signal for the vanus timing and the fuel cons. then it is not working correctly.
When you go 100km/h the dme reads ~19km/h and in 200km/h reads ~38km/h.
I think this effect the performace of the motor at high rpm

[328ijunkie]

It has no effect on the ECU short of top speed limiter and a soft rev limit at 5500 if it doesnt see a signal (related to the top speed limiter) according to multiple tuners ive spoken to. And ive never had it code (i have diag software, i dont just go by the CEL) personally.

[alndks]

If you let the car roll slow (2-3km/h) for a while (10-20 minutes like in traffic) it will shio the code and the rev limit 5500 appears. Then if you drive normal the rev limit is back at normal and the cel will never on.
Every obd2 car has correct speed in the dme even the e36 stock m52.
I think we must have the correct speed signal to be everything ok.

[328ijunkie]

like i said if the code does show up then it will do the stupid rev limit thing. Ive sat in traffic plenty of times in my car for over an hour stop and go and never had it code on me?
Well either way it would require a frequency multiplier
input ~0-420 (200mph) output ~0-~2300hz.

[alndks]

I have rev limit when i am in traffic and after in higher speed revs ok.
How can i connect a frequency multiplier?

[nando]

the simplest way would be to modify the software in the DME. Find where the "K factor" is, and divide the value by 5.33.

the other way would be to take the ABS wheel sensor input and convert it to a square wave.

the third way would be to modify the "A" output on the E30's cluster to output a 48 pulse signal rather than a 9 pulse signal. this only works if you aren't using the E30's CC or OBC.