tacr2man Posted June 23, 2011 Share Posted June 23, 2011 I was planning to use TD5 speedo in 90 that I have just fitted 300tdi EDC Auto , as that powertrain has electronic speedo, but it would appear that transducers operate differently. The Vehicle Speed Sensor (X190) sends a signal to the speedometer in the form of voltage pulses. The pulses are filtered by a Vehicle Speed Sensor Buffer inside the speedometer. The voltage alternates between battery voltage and 0 volts 6 times per wheel revolution. The speed sensor signal is also sent to the Engine Control Module (Z132). I am not 100% certain what ECM uses the speed pulse for, but think its just a matter of pulse or no pulse rather than utilised as a true speed signal ? Fitting a TD5 speedo would be easy enough using the excellent info provided on this forum , but I would still need a compatible signal for ECM . Would it be possible to make an emulator to feed the required pulse to the ECM being switched on an off by the signal to the TD5 speedo , so that the ECM knows when vehicle is moving. Electronics is way outside my s.o.e. so any help will be gratefully recieved. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 23, 2011 Share Posted June 23, 2011 The TD5 speedo also outputs a pulse to connect to the ECM on a TD5, would that be suitable as your pulse to ECM on your build? You can see it labeled as pin 1 on this post http://forums.lr4x4.com/index.php?showtopic=14892&st=20&p=160740entry160740 Is that any use? Quote Link to comment Share on other sites More sharing options...
landroversforever Posted June 23, 2011 Share Posted June 23, 2011 Td5 transducer will fit in the 300tdi drivetrain as it has an LT230? unless you have fitted a BW transfer box? Quote Link to comment Share on other sites More sharing options...
tacr2man Posted June 23, 2011 Author Share Posted June 23, 2011 CW you could well be right , I know the ecu on efi discovery just needs a pulse , so used an RRC in cable unit and that workd oK . Quote Link to comment Share on other sites More sharing options...
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