E30ix + ABS + standalone ECU?

[Nisse Järnet]

I think i read somewhere that you had to do something with the ABS unit when going standalone ECU to still have the ABS functional?

Am i right? And what do i need to do? :)

[spdracrm3]

ABS is completely independent of ECU and therefore works on its own, but on the IX the ABS controller does generate a signal that is sent to the ECU to open the IAC motor to reduce engine braking on decel (this could cause all 4 wheels so lock if drastic enough on an AWD car ,not good), it uses the extra mercury switch that sits by the left shock tower to determine deceleration rate and if necessary tells ECU to open IAC to reduce engine braking as lockup could occur

so if you want to maintain this function on your standalone you need to use this input and program accordingly (Nando knows what the signal generated is ,its posted on here somewhere also), if you dont want to you can just leave that wire from ABS to ECU with no issue but at your own risk....

[Nisse Järnet]

Found some wiring diagrams last night so now i know pretty much how everything works :)

I dont care about the engine braking, just want the ABS to work normally.

[nando]

I've covered this several times. Ground pin 17 of the c101 with a 1k resistor.

The signal is just an on/off, it feeds directly into the ICV circuit of the dme. All it does is force it to open the icv.

[Nisse Järnet]

I've covered this several times. Ground pin 17 of the c101 with a 1k resistor.

Do you know why some people doesn't need to do that? Is it a early vs late model thing?

I already found pin 17 so its no big deal but I will leave it for now and see what happens :)

[nando]

Bmw sometimes did it as part of a recall

[Nisse Järnet]

With the adaptor harness?

[nando]

Yeah its an add on peice

[Nisse Järnet]

So it would be easy to spot if its there :)

Could have something to do with pin 20 as well maybe?

Pin#20 - - ABS power – In some late model cars the ABS system gets its turn on signal from the Main relay. This connects from the Main relay to c101 then to the ABS module. Without this hooked up you will have no ABS.

[nando]

No. That powers the abs relay, although you still need it hooked up.

[Nisse Järnet]

I read that it worked for some but not for others, so maybe some left pin 20 unconnected? I don't know, I'll just have to see if it works or not :)

[nando]

Pin 20 is only used on airbag cars

Early cars have an abs relay under the dash

[Nisse Järnet]

Oh, OK!

I have a abs relay on top of the abs ecu on both my E30s.

[nando]

Then leave pin 20 disconnected :)

[Nisse Järnet]

Yeah I just checked, pin 20 is empty :)