sargejnr Posted November 16, 2009 Share Posted November 16, 2009 can anybody shed some light on what the perpose of the wire on number 4 injector on a 300 tdi auto? Quote Link to comment Share on other sites More sharing options...
BogMonster Posted November 16, 2009 Share Posted November 16, 2009 Needle lift sensor I think, tells the ECU when the injector is opening so it can see the injection timing Quote Link to comment Share on other sites More sharing options...
cipx2 Posted November 16, 2009 Share Posted November 16, 2009 That's correct. The long version: - the wire goes to a coil around the moving part inside the injector connected to the needle - when the injector pump injects the fuel, the needle lifts up and this make the coil generate an electric impulse - the impulse is used by the ECU as a feedback to check the result of what it ordered the injection pump to do in terms of the timing advance; i.e ECU sets the timing at the injection pump level and then checks the result comparing the impulse from the 4th injector with the one from the cranckshaft sensor. Quote Link to comment Share on other sites More sharing options...
sargejnr Posted November 16, 2009 Author Share Posted November 16, 2009 what would happen if the wire was to break or lose contact somehow? Quote Link to comment Share on other sites More sharing options...
cipx2 Posted November 16, 2009 Share Posted November 16, 2009 ECU declares a fault and I believe it then uses a back-up strategy with a different fuel map and reduced engine performance. Quote Link to comment Share on other sites More sharing options...
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