VSS problems

[Bruce Plecan]

-----Original Message-----
From: Tedscj at aol.com <Tedscj at aol.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, December 01, 1998 5:19 PM
Subject: VSS problems

Take a deep breath and start again.
What is the donor car/tranny
What is the recipent car/tranny.
Can you burn your own e-proms?.

Some 730's use a 4,000ppm A/C signal, and some use a 2,000 ppm D/C.
Bruce


>Hi,
>I just got and installed a VSS sensor on my car.  It is a four pulse sensor
>and also facilitates the attachment of a speedo cable for my cable driven
>speedo.
>The EFI system I'm using is a 7730  6cyl DIS system from an '89 corsair
with
>stock (but updated) EPROM.  The transmission is a 700r4 from an 88 Astro.
I
>am using the original cable drive gears in the trans.
>The problem is that my scan tool is only reporting about 10mph when I'm
>actually doing about 60mph, and about 5 when I'm going 30, etc.
>My speedo is still reading the proper speed, so I know the cable (and thus
the
>VSS) is spinning the correct speed.
>My manual states that the computer requires 4000 pulse per mile, so I know
I
>have the right sensor.
>Why is the sensor so far off?  Is there something I'm missing?  Are the
VSSs
>supposed to spin 6x faster than the cable driven speedos?  And if so, why
do
>they even bother making aftermarket VSSs like this if they won't even work
>with cable driven speedos?
>I also checked the harness and there is only .4 ohms in each wire from
where
>ii connects to the sensor to where it plugs into the ECM, so I don't think
>thats it.
>Does someone know of a way to test the sensor on the bench to see if its
>working properly?  I had to "modify" it to make
>it fit, so I can't return it (and it cost me $60!)
>
>Thanks for any ideas,
>Ted
>