Electric wiring question

YING

YING

Pittsboro,NC
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On my electric speedometer wiring it states “if using dedicated ECU supply’,what does ECU mean.Excuse my ignorance on this but I sent my speedo out to have it repaired by a very competent shop and he told me that it is fine after thorough inspection. I reconnected everything and everything works except no needle movement. I have replaced the sensor cable with the new style twice and cannot figure out what I am doing wrong.
Thanks,
Mike
 
Engine Control Unit...the computer unit on modern machines....so basically it is referring to a dedicated power line to a modern controller. This should be powered on with few/no other devices that could introduce electrical noise or voltage drop.
 
Mike,
Happy New Year to you. Where did you purchase the E/ Speedometer? Maybe contact them for a troubleshooting response.
I think cNw sells these as well as A/N. Others have had issues with the Electronic Speedo's in the past. I think Matt Rambo has a step by step
mode of getting them to work. Do these units need a GPS module?
I just rebuilt my old smith unit and it is steady as a rock on the needle again. It use to swing or wobble about 10 mph before the rebuild.
I'm sticking with old tech. ;)
 
CanukNortonNut said:
Do these units need a GPS module?
Click to expand...
No, they just need a pulse with the right frequency relative to the wheel diameter and the right Volts. You can use a GPS module to save the bother of either buying a fake smiths gearbox that generates the pulse or a sensor and disc with rotating magnets but it needs to be configurable so the pulses are correct.

For another project where I used an Aprilia electronic speedo I used a similar kit to one of these instead of fabricating a sensor mount and disc.

 
YING said:
On my electric speedometer wiring it states “if using dedicated ECU supply’,what does ECU mean.Excuse my ignorance on this but I sent my speedo out to have it repaired by a very competent shop and he told me that it is fine after thorough inspection. I reconnected everything and everything works except no needle movement. I have replaced the sensor cable with the new style twice and cannot figure out what I am doing wrong.
Thanks,
Mike
Click to expand...
Check your sender arrangement. Something as simple as the gap between magnet and pick up being slightly too big will result in no signal. And no signal = no needle movement.
 
Tornado said:
Engine Control Unit...the computer unit on modern machines....so basically it is referring to a dedicated power line to a modern controller. This should be powered on with few/no other devices that could introduce electrical noise or voltage drop.
Click to expand...
Tornado,
After I started having this problem I went ahead and ran a dedicated wire to power this unit that is fused according to the factory recommendation.Everything including the electrical tach works properly other than the speedo needle. I am going to get back with AN to see what they say.
Thanks,Mike
 
kommando said:
No, they just need a pulse with the right frequency relative to the wheel diameter and the right Volts. You can use a GPS module to save the bother of either buying a fake smiths gearbox that generates the pulse or a sensor and disc with rotating magnets but it needs to be configurable so the pulses are correct.

For another project where I used an Aprilia electronic speedo I used a similar kit to one of these instead of fabricating a sensor mount and disc.

Click to expand...
Kommando,
I looked at the unit from Ali Express and I don’t understand how it works and could I use this on my Smiths(CAI) speedometer?
Thanks,Mike
 
YING said:
Kommando,
I looked at the unit from Ali Express and I don’t understand how it works and could I use this on my Smiths(CAI) speedometer?
Thanks,Mike
Click to expand...
That is not the seller I bought from but it matches the pics, so you need to do your own research, you can ask the seller but Aliexpress sellers may not know much about what they sell. You need to know the Voltage of the signal from the sensor, its normally 5V as that is the V that electronic works at including ECU's and no doubt what the Speedo is looking for. You supply 12V to the sensor and internally it drops it to 5V for the signal wire.

I bought it as an experiment plus I do deal with repairing modifying ECU's etc and know by testing the wires which is 12V and which is 5V. If that's not for you then leave it be but AN also use much the same box.

andover-norton.co.uk

Andover Norton - GPS MODULE FOR SMITHS ELECTRONIC SPEEDO - 06.7904/GPS

GPS MODULE FOR SMITHS ELECTRONIC SPEEDO
andover-norton.co.uk
 
Brain hurts again .
But I do like the idea of a dedicated power source not affected by power surges and major drops such as hitting the e- start button .
The reset button was getting a workout .
 
kommando said:
That is not the seller I bought from but it matches the pics, so you need to do your own research, you can ask the seller but Aliexpress sellers may not know much about what they sell. You need to know the Voltage of the signal from the sensor, its normally 5V as that is the V that electronic works at including ECU's and no doubt what the Speedo is looking for. You supply 12V to the sensor and internally it drops it to 5V for the signal wire.

I bought it as an experiment plus I do deal with repairing modifying ECU's etc and know by testing the wires which is 12V and which is 5V. If that's not for you then leave it be but AN also use much the same box.

andover-norton.co.uk

Andover Norton - GPS MODULE FOR SMITHS ELECTRONIC SPEEDO - 06.7904/GPS

GPS MODULE FOR SMITHS ELECTRONIC SPEEDO
andover-norton.co.uk
Click to expand...
Thanks. I appreciate your information.
Mike
 

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