7730 ecm 40 tooth tone ring

[1project2many]

Yes, that's A/C.

[misterpat]

Now I'm wondering. If this will work, but only be close, not right. Would I just be better off running a drac?

EDIT:

Can I even use a drac with the 7730 ecm? It outputs square wave, correct?

[RobertISaar]

you can feed a 7730 a square wave VSS signal, just need to move the VSS input wire to a different pin and change a flag. AFAIK, every mask run on the 7730 supports the "optical" VSS input.

[misterpat]

Sounds easy enough. Anyone know what pin is for the square wave input?

So I got this straight.

1. Repin the VSS input to ??
2. Re-jumper the drac for my proper multiplier.
3. Change my bin to use the square wave input "optical" at 4000ppm.

Correct?

Thanks!

[1project2many]

Yes. Pin C6. Set up the DRAC to produce 2000 pulse per mile. Clear the "magnetic VSS present" bit 6 @ 0x0018. The speed sensor pulse per mile divider will no longer be used.

[misterpat]

Awesome, Thanks! So once that "magnetic VSS present" is cleared, the "Road Speed Constant" at 0x15 is irrelevant? Or does it need to be set to 2000ppm as done here:

http://www.gearhead-efi.com/Fuel-Inj...-on-a-7730-ECM

[1project2many]

The RSS affects the signal sent from the ecm to the instrument cluster.