disco111 Posted December 10, 2009 Share Posted December 10, 2009 Hallo everybody A year ago I replaced the harness to the injectors inside the cylinderhead because there was oil in the plugs and wires.I cleaned the plugs and made a barrier in de wires just before the red plug by soldering the seven wires.Each time I reach the speed of 100km/hr the engine starts to make a strange noise(I think there is still a problem with oil in the harness). Does anywone as an exact explanation whats happening in the plugs or wires,is there an electrical leak current between the wires or inside the plugs so that the injector exitation get disturbed??? A new harness between the cylinderhead and the ECU is very expensive (+400£).I can make a new harness myself but first of all I wish to know whats exactly happening inside the wires. Many greetings from Gent Belgium Martin. Quote Link to comment Share on other sites More sharing options...
Guest Posted December 10, 2009 Share Posted December 10, 2009 Hallo everybody A year ago I replaced the harness to the injectors inside the cylinderhead because there was oil in the plugs and wires.I cleaned the plugs and made a barrier in de wires just before the red plug by soldering the seven wires.Each time I reach the speed of 100km/hr the engine starts to make a strange noise(I think there is still a problem with oil in the harness). Does anywone as an exact explanation whats happening in the plugs or wires,is there an electrical leak current between the wires or inside the plugs so that the injector exitation get disturbed??? A new harness between the cylinderhead and the ECU is very expensive (+400£).I can make a new harness myself but first of all I wish to know whats exactly happening inside the wires. Many greetings from Gent Belgium Martin. Hi Martin, Would a problem at a certain speed indicate a problem within the drive train, not the engine, as surley your engine will rev through the same arc in each gear? and you should experience this problem at the top end of gear? I used to get a noise problem at around the same speed which was a front wheel bearing on it's way out. Just a thought Quote Link to comment Share on other sites More sharing options...
disco111 Posted December 10, 2009 Author Share Posted December 10, 2009 Hallo Jason It as certenly nothing to do with a mechanical problem in the drive train.At a speed of apprx. 100 km/hr the engine starts to produce misfires(aprox.2400 rpm).Normally I dont drive more then 100km/hr and each time I reach this speed the engine starts to misfire.This week however I was on the highway and passed 120 km/hr whitout the typical noise that I normally had.Then I realised that on that moment the engine was running 100% normally and that I have to look for the reason of the misfires.(oil in the wiringloom). I know the problems of the oil in the harness but nobody until now on this forum explaned whats realy going on in that harness and in the connection plugs. I have seen on my multiscoop that the signals to the injectors shows very sharp pieks so I think that there is a certain electrical leak current between the contacts of the plugs contaminated with oil wich in turn produces the misfires from a certain regime of the engine. As anyone done some research on this subject,anyway this week-end I am gone do some tests and measurments. Many thanks and greetings from Gent Belgium Martin. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted December 11, 2009 Share Posted December 11, 2009 Not wishing to be nasty but I wouldn't honestly try making a harness myself - it might work but what if it doesn't? I would try to find a good second hand harness for testing purposes to rule that out as the problem (or not) - the other thing that can produce a misfire under load is dodgy fuel pressure. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted December 11, 2009 Share Posted December 11, 2009 Have you tried cleaning any oil out of the ECU or the main harness? While replacing the injector harness stops more oil getting into the loom, the oil thats in there will continue to creep out the wires into the ECU. I think the problem is usually caused by the oil reaching the ECU itself, and messing with the electronics, rather than shorting out the wires directly. Quote Link to comment Share on other sites More sharing options...
mark1200 Posted December 11, 2009 Share Posted December 11, 2009 think about this logicaly oil gets into the injector wireing and by capilary action gets through the wires to the ecu plug, this is where the oil upsets the voltage to the ecu causing misfires. the soultion is to replace the injector harness and clean out the ecu plug of all oil, job sorted and it will run properly. BUT there is still oil in the main wireing loom and it can take many months for capilary action to suck all the remaining oil out of the loom. so its replace the main wireing loom or just keep cleaning out the ecu plug till the oil stops coming through the wires and this can take several thosands of miles depending on how long it was before you changed the injector loom. Quote Link to comment Share on other sites More sharing options...
disco111 Posted December 12, 2009 Author Share Posted December 12, 2009 Hallo L.R.lovers First of all thank you very much for your answers.A year ago I noticed OIL in the harness,plugs and ECU plug,I changed the harness inside the cylinderhead cleaned the plugs and prevented that oil could come in the ECU plug by cutting the 7 wires (2 earth connections and 5 signal lines from the injectors)I soldered the wires on both ends and placed a connector in between. It is now impossible for the remaining oil in the harness to reach the ECU plug.The only things that remains is the risk for problems in the plug on the cylinderhead and the insulation of the harness itself.(I think). As I promised, a hour ago I have done some measurement on the injectors,I placed my multiscope meter on each of the lines and noted at 740RPM a peak tension of 100 volts and when revving at 2000/3000 RPM more then twice that tension !!!! I can now understand that the oil between the contacts can lead to an electrical by-pass between the contacts of the connectors or even between the wires themselves. Now I am gone check al the connectors again cleaning them and inspect them before taking any action. See also my message:"TD5 INJECTION TIMING",on that subject there is also a lot to explain I think. Many greetings from Gent and thanks again,untill later. Martin. Quote Link to comment Share on other sites More sharing options...
disco111 Posted December 26, 2009 Author Share Posted December 26, 2009 Hallo everybody See message from robK007 on the Discovery forum please,problem solved by lowering the turbo pressure of 0.1bar from 1.1 to 1.0bar,the MAP sensor informed the ECU that the turbo pressure was to high so the ECU lowered the quantity of fuel injected.(the so called misfires !!!!) Many greetings and thanks to robK007 Martin Gent Belgium. Quote Link to comment Share on other sites More sharing options...
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