Speedometer signal

[Hocky]

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!

[SS2win]

Sorry I can't help with your question but thanks for posting! That is a great project you have there and made my day start out 100% better! :rockon:

[doubledip]

have seen this done before...

instead of using the signal wire from the pcm, hook the speedo input of the speed sender TOShi wire...

basically the signal from the PCM is not strong enough

[Hocky]

Great info!

But if I connect to the transmission speed sender I can not adjust the number of signals to get the correct speed?!?
You can of cource reprogram the VDO gauge but that is over my head anyway.

Maybe you can amplify the signal from the ecu?

[doubledip]

that is correct .... but you can either buy signal amplifier boxes or digital ratio boxes to fix either of the problems... we sell both types

[Hocky]

Thats sweet!

Maybe for other members of this forum (I will send you a email anyway).
What would you recommend and why?

[doubledip]

with it being a vdo gauge have you calibrated it yet?

i.e. driven the distance that it requires...


a trap with the VDO gauges is that they wont register on the needle till the calibration stage has been completed. (it is known as the auto calibration stage)

[Hocky]

It is a used VDO speedo from a Volvo 242 from the 80s.
It has a good 265850km on it so it must be calibrated by now or?

[doubledip]

can try a 1k resistor between 12v and the signal wire into speedo (act as a pull)

[Hocky]

Thanx, I will try that!

Will post the results, if no success I will for shure make som purchases.

[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

?