Speedo Sensor / Wiring
Discussion
I ordered a set of gauges from Speedy Cables a while back to replace mine. After finally getting the car back on the road, I can't seem to get the right connections to the speedo.
My original speedo was the 'clicky' type (1994 Pre-Serp/T5 - sensor disc on prop). This ran through a TVR bodge box which sent a signal to the original speedo and to the ECU.
Sent everything to speedy cables and they returned it, stating I would no longer need the bodge box (also as I have ditched the original ECU and fitted Megasquirt).
Problem now is, removing the whale tale, I can see a cable running to the diff, which has Black/Grey cables in it. Black is GND, and Grey is connected to the speedo (signal?). Looking in the 'bible' the sensor in there shows a IGN supply (conencted to the reverse switch), so is this a different type of sensor on my car - any ideas on what kind and what kind of signal it should be outputing?
My original speedo was the 'clicky' type (1994 Pre-Serp/T5 - sensor disc on prop). This ran through a TVR bodge box which sent a signal to the original speedo and to the ECU.
Sent everything to speedy cables and they returned it, stating I would no longer need the bodge box (also as I have ditched the original ECU and fitted Megasquirt).
Problem now is, removing the whale tale, I can see a cable running to the diff, which has Black/Grey cables in it. Black is GND, and Grey is connected to the speedo (signal?). Looking in the 'bible' the sensor in there shows a IGN supply (conencted to the reverse switch), so is this a different type of sensor on my car - any ideas on what kind and what kind of signal it should be outputing?
Thank you for the pointer. Don't know why I put down Speedy Cables as the gauges are ETB - losing my mind!!!
Anyway, I had removed the 'blue wire' as it was connected to the original speedo. As it turns out, I was expecting a 'hall effect' sensor, with IGN +ve supplied via the reverse circuit.
However, it looks as if it is a VR sensor, and the grey wire is signal, with the black connected to GND. Bit confuisng as the original speedo had three connections. IGN, GND and signal.
The ETB gauges require 4 connections IGN, GND, and the wiring diagram shows the VR sensor connected to pins 7 & 8. So, simple jumper to pin 7 of GND and it all works!!
Happy days! Just need to calibrate it with a Satnav, then try and get my head round tuning this Megasquirt correctly!!
Anyway, I had removed the 'blue wire' as it was connected to the original speedo. As it turns out, I was expecting a 'hall effect' sensor, with IGN +ve supplied via the reverse circuit.
However, it looks as if it is a VR sensor, and the grey wire is signal, with the black connected to GND. Bit confuisng as the original speedo had three connections. IGN, GND and signal.
The ETB gauges require 4 connections IGN, GND, and the wiring diagram shows the VR sensor connected to pins 7 & 8. So, simple jumper to pin 7 of GND and it all works!!
Happy days! Just need to calibrate it with a Satnav, then try and get my head round tuning this Megasquirt correctly!!
Spoke too soon!!!
Ran it up and down the road (to about 30mph) before putting the whole dash back together, only to find once on the road - it won't go above 30mph - in fact the faster you go - the slower it reads!!
Might have to look at a different sensor? The one I have is mounted above the disc on the prop and looks like a real pain to get to!!
Damn!!! Any other (lazier) ideas welcome....
Ran it up and down the road (to about 30mph) before putting the whole dash back together, only to find once on the road - it won't go above 30mph - in fact the faster you go - the slower it reads!!
Might have to look at a different sensor? The one I have is mounted above the disc on the prop and looks like a real pain to get to!!
Damn!!! Any other (lazier) ideas welcome....
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