Speedometer signal

[Aloicious]

I am currently building a Volvo 242 with a procharged LS1 engine in it.
The transmission is a T56. The complete engine package comes from a Camaro SS 1999. Some pics can be found at http://www.hocky.se.

Got one problem with the speedometer. I have retrofitted one electric VDO speedometer from a newer Volvo car and is trying to get this to work.
Problem is that it wont move...not at all :(

Anyone done any similar?
What type of signal is generated from the ECU?
Is this the same type of signal that comes from the transmission?

Thanx!

I don't know what the VDO gauge requires as far as signal strength like you've been talking about. but the VSS signal reluctor wheel inside the T56 trans is a 17 tooth reluctor, many other trans' use a 40 tooth reluctor. when I swapped from a 4L60e to the T56 I ran it once before recalibrating the speedometer info and with the 40 tooth settings in there the speedometer would barely move, you might want to make sure your settings are correct for the 17 tooth reluctor.

[Ira]

As I recall the output on the 1999 only pulls down so to get a signal out of it you'll have to add a pull up resistor to 5 or 12V. This is one of those times when having access to an oscilloscope comes in real handy. The next year they had an internal pull-up.

Ira

[Hocky]

I did try with a 1k pullup with no result :(

I think the VDO speedometer is triggered by a hall sensor in the rear axle as standard om the Volvo where the speedometer is from.

ecu - signal converter - speedo
or
T56 sensor - pulse converter - speedo

?