The speedo on my newly acquired Libra over-reads somewhat, at 70mph on my GPS the needle is over 80 on the speedo. I've seen a few comments about calibrating the speedo but no information on determining the settings required. On the Koso in the Midas you measure the distance covered by a single rotation of the driven wheels in mm, is this something similar?

A simple walk-through would be much appreciated.

Rich

I would just change the 'pulse' number until the speedo reads the same as your GPS.
They were originally set to about 4100 when new. But it obviously depends on what wheels, tyres, gearbox, final drive ratio, etc you have fitted.
To get the pulse number up, press & hold the button on the speedo, then turn on the ignition. Keep holding the button & it will scroll between AUtOCL, PULSE & AdJUSt. Release the button when PULSE is showing. You can then change the number - one digit at a time.
Hope this helps, if you need more info i have the original calibration instructions somewhere!!

Thanks Sven,

I've no idea what it is currently set to, the car is running 205/45 tyre on 15" rims, no idea what the final drive is but it's low. I understand the drivetrain originally came from a ZT 160.

The current setting appears on the display when you follow Sven's instructions. Increasing the number will reduce the speedo readings. For example: If the current number is 4100 and your speedo reads 82 when your actual speed is 70, change the number to 4100 x 82 / 70 = 4803.

Instructions at http://www.caigauge.com/documents/pdfs/pil017-368.pdf Pre 2004.
or http://www.caigauge.com/documents//product-instructions/spedometers/speedometers/pil042-460-435.pdf Post 2004

From http://www.caigauge.com/product-instructions

I've not tried it as mines pretty close already but reading the instructions I found online (Sven must have the same ones!) I think it should show the current setting when you get to the pulse setting bit.

Mine came to me with a R65 box and 205/45/16's, when I changed to a PG1 (with the VVC final drive) the speedo read almost identically and checked against GPS was reading slightly high so ideal. From memory when the speedo says 70 the GPS says 66 so just on the right side for comfort.

I might have a play to see if I can get it to tell me the pulse rate.

Are you sure you are on 15" rims Rich? I think most libras came with 16"?

If your gearbox still has the part number sticker on it you can get the final drive from the code e.g. MGF's are C4B or C6B, the 4's have the lower final drive.

Yes, sorry they are 16". Fat fingers strike again.

I managed to get into the settings and have a play, thank you for the link to the instructions, I'm hoping they cover the shift lights too as the red is on by 5k revs.

You got shift lights? You must have the posh version! VVC is good for 7200. Sounds lovely between 6500 and the redline!

Yep, in the rev counter. The first two come on together at about 4250 and then the red is up at 5000, even though I know it is good for more it's a bit off-putting having the red screaming at you half way though an overtake.

Found this. Its for a racetech analogue tacho with shift lights but might be a similar set-up?

Each shift LED is independently adjustable within the limits of
the non-compressed scale. To alter the settings at any time
(engine running or not) press and release the menu/select
button once. The green LED will illuminate first and the
pointer will move to the current green LED threshold setting.
To raise the threshold, press the set/adjust toggle switch—
either hold down to increase at a constant rate, or press and
release to move in tiny steps. If the maximum is exceeded
then the setting will cycle back to the minimum.
To adjust the amber LED, press the menu/select button
again, this time the amber LED will illuminate and the pointer
will move to the ‘green’ set point. Using the toggle switch as
described above, move the pointer to the desired set point.
Note: in setting the ‘amber’ start point, you also set the
‘green ‘ off point. Press the menu/select button again and use
the toggle switch to adjust the red LED. Again, in setting the
‘red’ start point, you also set the ‘amber ‘ off point.
After setting each value, press the menu/select button once
to move to LED intensity setting or press twice to return to
normal operation.

These should be the the instructions for your tacho - works for mine. http://www.caigauge.com/documents/pdfs/m-sport-prosport-tacho036-353.pdf

Unless they are very well hidden I don't seem to have any buttons or switches to work with, I've emailed the company but not heard anything back yet.

Have you checked under the dash, around where the metro fuse/relay box is? That is where I fitted some of the buttons for my instruments, sure I got that idea from someone else!

Yep, just been under it again to double check with a torch.

These are the instruments fitted..

I have this type of rev counter the switches you are looking for will probably be behind gauges out sight of iva inspector you will have to take top of dash of to look for them

Thanks Mark, I knew the IVA was funny about balance bar adjusters and so on, but not set up switches too.