viper Posted August 23, 2013 Share Posted August 23, 2013 At 8am tomorrow morning I am expected to be at scuterneering for the open sport nationals but 2 days ago the car developed a misfire and is running in 5. Iv checked all I can. Voltage going to spark, Coils, Injectors Compression was checked at Thor 2 weeks ago and all was good, since then all I have done is drive to the falcon for the midlands meet. I will recheck compression today. All I can do is go over it all over again. Can anyone tell me what voltage I should see across injectors and coils? Any assistance would be greatly appreciated given the urgent circumstances Quote Link to comment Share on other sites More sharing options...
mellonman Posted August 23, 2013 Share Posted August 23, 2013 wiring to the coild packs can be damaged took me along time to get pinpointed and sorted , its normally coil clips, change your plugs regardless of age i have had a dodgy plug before http://www.mkiv.co.uk/vbb/showthread.php?289482-cold-misfire-*updated*-HELP Quote Link to comment Share on other sites More sharing options...
Scott Posted August 23, 2013 Share Posted August 23, 2013 Give the offending plug tip a clean with some fine emery paper. As above, change the coilpack clip of the offending cylinder, those always cause misfires, very common fault. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 23, 2013 Share Posted August 23, 2013 (edited) Confirm which is the dud cylinder. Do another compression check on it to be 100% sure it's OK. Swap the 2 coils covering the dud cylinder and its neighbour with those of another pair of cylinders. Is the dud cylinder now OK and another one dead? Dead coil! Same with plugs, swap plug from dud cylinder with the one from a running one. No change yet? Suspect injector or injector wiring. If Racelogic is fitted consider this could be an issue. Swap injectors from known good cylinder to dud. No change? Check 12 volts is to one side of dud cylinder's injector with ignition ON. The other side should be grounded by the ecu on each firing stroke for that cylinder. A noid light or scope will confirm. No ground being pulsed? Wiring issue back to ecu or resistor pack if fitted. Resistor pack issue if fitted. Wiring from resistor pack back to ecu issue. ECU conector plug issue. Ecu issue. Simples! Edited August 23, 2013 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
viper Posted August 27, 2013 Author Share Posted August 27, 2013 Hi chris, yep we traced it back to the ECU putting out 6volts to injector 6, but even after changing the ecu it now runs terrible. iv knocked it o nthe head and will be rebuilding everythign anyway for daywalker so i will replace the coils just to be sure anyway Quote Link to comment Share on other sites More sharing options...
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