VSS signal vs Drac

[Nolan]

>Search for drac in the diy_efi archives ...
>
>I did and what I read leads me to believe that the DRAC is a frequency
>converter that is used to drive the speedometer.  Do you have the
>schematic?  If so just do what they did.  Just give the ECM the
>frequency it expects, and be aware that some count pulses and some count
>zero crossings.  YMMV
>
>- --steve
>
>Nolan wrote:
>> 
>> Hi I'm hoping some one can give me some info.I'm building a pulse generator
>> with a 555 to make aake VSS signal. I order to feed this signal to the ECM
>> do I have to go thru the DRAC (its a 7749 Syclone computer) or can I
feed it
>> directly to the ECM?
>> 
>> Thanks
>> 
>> Nolan

Hi Steve

Thanks for replying!!! How can I determine which mine is? It uses 2002
pulses per mile
which I think is a dc wave so it would only read pulses.But how can I find
out for sure?
I'll start looking thru the Archives.

Thanks Nolan