I have a 1983 US-specification XJ6, which was retrofitted by the original owner with a contemporary Jaguar XJ6 manual transmission. When that later failed, a shop replaced with a Tremec 5-speed for me, and adjusted the speedometer drive ratio with a mechanical ratio adjuster between the transmission and the speed sender. When the drive gear in the transmission failed, my current repair shop proposed replacing the sender with a magnetic induction sender on the drive shaft, and an electronic ratio adjuster from Dakota Digital. This works fine for the speedometer/odometer and the cruise control, but the trip computer is only counting about 25% of the pulses.
The wiring diagram indicates that the signal goes to all three loads, plus the (now disconnected) service interval counter. (Unplugging the service interval counter, for which I no longer have the lamp in any case, made no difference.) Unplugging the speedometer and cruise control made no difference, so it is probably not a question of too many loads on the Dakota Digital output.
We tried several trip computers, and all behave the same.
The shop and I each tried spinning the stock sensor (both the one which was working, and a brand new one), with +12 VDC applied to the input wire and the case grounded, but did not see a signal, so we could not establish what the signal should look like, to compare to the Dakota Digital output.
- What is the expected waveform? If a square wave, what is the voltage and duty cycle?
- Is there a way to bench-test the stock sender, with an oscilloscope on the output? Does it require a particular load resistance? How must it be grounded? (Grounding the case does not seem to work.)