New to EDIS 4 , don't quite get the wiring

[sammy]

Sorry for the dumb question, but what’s the OBC?

Anyhow ....a friend of mine is an electronics engineer.
I got hold of a spare Alfa Tacho the other day and I got him to reverse engineer the circuit, so now we have a good idea of how it works.
I just rigged up an EDIS test harness using a spare trigger wheel, sensors etc...
I’m giving him the harness tomorrow, As he has an Oscilloscope, he will try and capture the signal coming from pin2 (Tacho).

Hopefully it’s just a matter of comparing the two and putting together a circuit to convert one signal to the other.

It’s funny but I haven’t been able to find a image of the signal for pin2 anywhere on the net.
Another thing I haven’t been able to find in a circuit diagram for the EDIS 4 internals that would have been handy too.

I see if I can get anything worthwhile from him and post it for others.

Sam

[trakkies]

OBC - on board computer. Gives MPG - distance before fuel needed, etc.

The EDIS IDM signal is IIRC positive going pulses of approx 9v p to p. But this was just looking on a tiny hand held scope so I could be wrong. Again.

[sammy]

I still havn't got the tacho sorted, but now I have the EDIS and MSII v3 connected.
I havn't got it running fuel yet, I was hoping to get MS to look after the Ignition through EDIS first, then when it's all bedded down and running for a little while, I'll dump ther carbs and convert to EFI.

So far I've only got the TPS and the EDS SAW & PiP wired through the relay board.

So the problem I have is that in Megatune the Revs are only showing about 50% of what they should be. i.e. at idle I reckon the car is really doing about 900 revs, but Megatune is showing about 450 revs

anyone have any ideas?
I thought the EDIS would automatically provide the tach signal through PIP?

Sam.