[Richard]

Does anyone know the cal number for a VDO electronic speedo on a Detroit 60 with Allison trans? 

Mine lost its mind, and I don’t have a good starting number. Mine will not do the autocal that the newer ones do.

[MrE]

VDO SPEEDO ISSUE
by Lorne Goldman at the eMog Pub (2001)

The later digital mileage VDO speedos can certainly develop anomalies. Most often a replacement is less frustrating and cheaper than attempted repairs. However, VDO will check it out for you for free if you indicate that you will be purchasing another if it turns out bad.  If they find nothing, then take the time to locate the little capacitor behind the speedometer. It is very small and hidden in a wire shroud. This capacitor can become defective and will have the speedo give bizarre readings. Replace it, it only costs a few dollars.

Calibrating a new VDO Odometer

VDOspeedoCalibration.pdf

[Richard]

Thanks Jon.

Like I said, mine lost its mind sort of. When I replaced my DDEC III with a DDEC IV, the MPH was suddenly 25% off. In my first attempt, not understanding how the cal process worked, I inadvertently blew away the pulse count calibration number in the speedometer. I was looking for a starting place if someone knew the number.

And I don’t know if there is something awry with mine, or it’s an early version, but the autocal method does not show up when I initiate the sequence. It only gives me the option of manually inputting the pulse number.

[Jack Houpe]

I bought a GPS speedo on Amazon for less than $100, use silverleaf to keep up with mileage.

[Richard]

Yeah, the silverleaf is what I use.

It’s one of those, it’s there, it’s supposed to work things………………..