Vss on 165 ecm help!

[rr]

I'll go out on a limb here, this is something that you can try. The output
of the optical unit needs a pullup to 12volts. Then use a capacitor in series
to the ecm input. This will AC couple the digital signal. There was something
about this a while ago, should be in the archives.

IE: Use a 4.7 Kohm at the digital out to 12 volts. Then use a 0.1uf disk
capacitor
to couple that to the ecm vss input (in series).

BobR.

Mike Rolica wrote:

> I have one last thing to solve on my tpi s10 project.  I have a mech
> operated speedo and the prom is for 89 firebird 350 tpi   (apyu)  It has one
> wire -Brown for the vss.
> With the ign on I have 13v nothing connected.  I've tried the optical type
> but most I find are bunt out and I believe they are only dc pulse.  What do
> I need to send to the ecm?  What is it looking for in detail.  I have and
> inline gen. used on my 84 jeep grand wagoneer.  On my fluke meter it reads
> 4v ac.  how can I make this work?   And I am sure I will shoot someone if
> they start telling me to modify the code of go buy something from JTR. ;-)
>
> thanks, Mike R