I know there's a flag you can set to select a magnetic vs optical VSS. Now as I understand it, the 4000 and 2000 ppm outputs from the ECM are open collectors that get grounded for each pulse. Is there any flags you can set to turn those into 0-5V square waves?

 

I'm assuming you are refferring to B11, B12 and C1 outputs.
I thought thats what they are (Sq waves). I don't know for sure.
Why do you think they are something else?

 

Have a look at the schematics on ludis.

 

I think the outputs go through 3 state inverters. Unless my ECM is broken, I have never seen 5 volts on any of those outputs (as shown in the schematic - normal inverters). They are always ground switches.

So I'm guessing that means no way to change it via software.

 

What computer are you using, what kind of car?

 

7730. any.

 

If all you want to do is get a 0-5 volt swing, just grab the +5reference from the ECM, and stick a resistor from there to the signal output, say 4.7k or 10k. easy enough. If you want it to be 0-12v, wire it to +12v out of the ecm. (use these becuase they will be filtered nicely out of the ecm (or stick a capacitor or two at the voltage as well (.1uf, 1uf in parallel work great). No need for any software, you just need to complete the circuit.

this applies for any of the open collector outputs.

 

yeah, I was hoping I could do it via software. Oh well... Thanks guys