Electronic Speedometer

[1STMP]

I've installed a new 5"
electronic speedometer
and a 2 wire sending unit.
(727 trans)
In calibration mode the
speedo runs thru it's
normal courses but does
not count the pulses from
the sender.
Does the sender need its
own (seperate) ground?
The ground wire (now)
runs from the sender to
the guage.

 

[kiwigtx]

Hall Effect?

They have dip switches, and the easiest way to calibrate is running another car with a GPS besides, or behind.
Manually done and very effective.

 

[kiwigtx]

Does the sender need its
own (seperate) ground?
The ground wire (now)
runs from the sender to
the guage.

Sorry....cable needs to be a twisted pair with a screen to avoid interference from outside sources like ignition or MSD units etc.

 

[1STMP]

Hall Effect?

They have dip switches, and the easiest way to calibrate is running another car with a GPS besides, or behind.
Manually done and very effective.

Thanks for the response,
@kiwigtx

In calibration mode the
sending unit sends pulse
signals to the speedometer
over a set 2 mile distance.
It is a two wire hall effect.
The pulses are not reaching
the speedometer.
The speedometer ground
and power connections
are working, as the needle
goes thru the proper motions
in set up mode.

 

[kiwigtx]

Thanks for the response,
@kiwigtx

In calibration mode the
sending unit sends pulse
signals to the speedometer
over a set 2 mile distance.
It is a two wire hall effect.
The pulses are not reaching
the speedometer.
The speedometer ground
and power connections
are working, as the needle
goes thru the proper motions
in set up mode.

Are the speedometer and hall effect unit a matched pair - or compatible with each other?

 

[kiwigtx]

Try connecting the ground or screen at one end only - probably speedometer end......otherwise you can create a ground loop which could affect the results.

Also check polarity of your connections.

 

[1STMP]

Are the speedometer and hall effect unit a matched pair - or compatible with each other?

Yes, the Autometer
speedometer is compatible
with either a two or three
wire sender.
I was thinking of installing
a T-splice and running a
second ground to
somewhere on the engine
block.

 

[pnora]

Yes, the Autometer
speedometer is compatible
with either a two or three
wire sender.
I was thinking of installing
a T-splice and running a
second ground to
somewhere on the engine
block.

I would not ground it unless told to do so. Does the speedometer work at all? Are you sure the gear in the transmission is turning the sensor?

 

[1STMP]

I would not ground it unless told to do so. Does the speedometer work at all? Are you sure the gear in the transmission is turning the sensor?

I have yet to pull the sensor
to bench test it.
Yes, the speedometer goes
thru the calibration motions.
Without the completed
calibration there are no
pulses to count in the
speedometer, itself. The
pulses (in calibration mode)
are not being transmitted
to the speedometer.

 

[kiwigtx]

Not sure which gauge you have, but this video is on Summit Racing under the product information...

AutoMeter 4490 AutoMeter Ultra-Lite Series Speedometers | Summit Racing

 

[kiwigtx]

Found this on ebay also....

 

[pnora]

I have yet to pull the sensor
to bench test it.
Yes, the speedometer goes
thru the calibration motions.
Without the completed
calibration there are no
pulses to count in the
speedometer, itself. The
pulses (in calibration mode)
are not being transmitted
to the speedometer.

Thats my point. You may not be turning the sensor. It will go through the set up sequence and pass because it is seeing the sensor. You also did not answer my question. Does it work at all? I suspect not because it is not turning.

 

[1STMP]

Thats my point. You may not be turning the sensor. It will go through the set up sequence and pass because it is seeing the sensor. You also did not answer my question. Does it work at all? I suspect not because it is not turning.

If you mean by "work at all"
as it not reading any mph,
no it doesn't. But it does
work to the point of going
into calibration mode.
It won't read mph until the
number of pulses are
counted during calibration.
I understand that the sensor
may not be turning.

 

[Project66]

I installed an AutoMeter electronic speedo a few years ago. I had to use a sender, like the one pictured, to make it work with my car's original A904. Did you make sure to install the little square rod? If you left that out, you can do everything else right, and it still won't work.

BTW - I really like the gauge. It's dead accurate and easy to recalibrate if you change gear ratio or tire size. It's also compatible with the factory Tremec sender. When I did my TKX upgrade, it was plug-and-play.

 

[Project66]

The rod for my kit looked more like this.