94 Camaro

[David R Johnson]

On May 29,  2:47pm, Fahad Khoory wrote:
> Subject: 94 Camaro
> Hello,
>
> I am having a problem with my 94 Camaro. Any help would be greatly
> appreciated.
>
> I have swapped a T-56 in my Camaro that had 4L60E originaly. I have a
> problem with the speedometer. It reads too low. How can I correct  the
> reading? Everything else works fine. I've even reprogrammed the PCM. I
> also tried the Cyberdine(sp?) calibrater with no use.
>
> Fahad
>-- End of excerpt from Fahad Khoory


What year Camaro did the gearbox come from?  The 93 box actually uses a
different speedo connection from the 94 up (non electronic I think), so if your
speedo reads at all that is probably not the problem.  The 93 can be changed by
putting in a different size of plastic drive gear.

For the electronic speedo type, reprogramming the PCM is the way to go.  This
can be done by a shop appropriately equipped (sounds like you went with this
option), or using a Hypertech Power Programmer, which plugs into your PCM
diagnostic port.  In either case, it is important to know the correct rear axle
ratio for your application.  If the car was originally an auto, the rear axle
is usually 2.73:1 or 3.23:1.  Most sticks get the 3.42:1, but the options
available depend on the year.  You can find out what you have be reading the
glovebox build option codes.

I'm guessing that you still have the 3.23 gears that came with the auto, but
have a PCM program set up for 3.42's.  This would cause the RPM's to be lower
than expected at a given speed, resulting in a low speedo reading.  To fix it,
get the shop you had your PCM program done at to verify that the ratio in the
PCM matches the gears on the car.  It is possible that there are other
differences between the manual and auto PCMs that could cause this, but I'm not
aware of any.

For a lot of good info on Camaros, including details of the axle options and
codes, try the url:  www.f-body.org.  The FAQ there is great, and you might
want to join one of the excellent mailing lists for Camaros supported by that
server if you have further Camaro questions.

Hope this helps.  I will be on vacation for the next few days, but feel free to
e-mail me when I return (Wednesday).

Dave J.
94 Camaro Z28, supercharged.