steve_d Posted October 7, 2011 Share Posted October 7, 2011 Hi I'm working on a car with Ford coil packs directly driven from an ECU. Paperwork that came with the vehicle talks of the possibility that the ECU may not be working. The sentence said "we think we may have fried the ECU". The engine barely starts and tests show we are indeed missing sparks. What I wanted to do was test the packs, leads, plugs etc on the bench in order to eliminate them from the equation. Sounds simple enough. Connect power to the centre pin and flash the outer pins to negative. Didn't work. Earthed the coil pack...nowt. What am I doing wrong? Thanks Steve PS Not an MS ECU but the coil packs are the same. Quote Link to comment Share on other sites More sharing options...
mikeyb13 Posted October 7, 2011 Share Posted October 7, 2011 Wouldn't it be safer to just check the primary and secondary resistance? Quote Link to comment Share on other sites More sharing options...
mikeyb13 Posted October 7, 2011 Share Posted October 7, 2011 Wouldn't it be safer just to test the primary and secondary resistance? Quote Link to comment Share on other sites More sharing options...
steve_d Posted October 7, 2011 Author Share Posted October 7, 2011 Wouldn't it be safer just to test the primary and secondary resistance? I have done that and all was OK but that does not test the leads & plugs. I just thought it would be easy to test the lot but have so far failed. Steve Quote Link to comment Share on other sites More sharing options...
mikeyb13 Posted October 7, 2011 Share Posted October 7, 2011 The leads can be checked with a resistance test aswell. Might be a stupid question but did you have the spark plug earthed aswell? Quote Link to comment Share on other sites More sharing options...
ThreeSheds Posted October 8, 2011 Share Posted October 8, 2011 Assuming your coilpacks are like the one in the photo below (which has now been copied so many times I don't know who took it - apologies if it's yours and please don't sue ) then... You don't actually need to earth the plug-ends - just tape them together since the return path is down it's paired lead, as can be seen in this much copied shot: WRT getting them to spark in the first place, I am pretty certain (although it's a few years ago) that connecting the central (supply) terminal to +ve and brushing the outer contacts in turn on the -ve made mine spark. The problem with testing the leads etc is that if you have a duff lead or cap then (due to the paired nature) it will stop TWO plugs from firing... Hope this helps Quote Link to comment Share on other sites More sharing options...
steve_d Posted October 8, 2011 Author Share Posted October 8, 2011 Assuming your coilpacks are like the one in the photo below. Yes same 4 post pack. WRT getting them to spark in the first place, I am pretty certain (although it's a few years ago) that connecting the central (supply) terminal to +ve and brushing the outer contacts in turn on the -ve made mine spark. This is what I was doing in the workshop. Just tried it again at home with another coil pack and still get nothing so still have to be doing something wrong. Steve Quote Link to comment Share on other sites More sharing options...
SORNagain Posted October 8, 2011 Share Posted October 8, 2011 I have tried testing these coil packs in this way before - it didn't work either. I was just dabbiing a wire on the terminals. The problem was that you can't break the flow of current cleanly enough this way - you get an arc when you break the connection, which gives a slowly decaying primary current and no spark! I found an old ignition module kit which had an output stage that was a IGBT paralelled with a 250v zener. Worked great using this. You could try putting a condenser off and old distributor across where you are breaking the connection. This will allow the arc to extinguish and hopefully solve your problem. At the time I couldn't believe that dabbing a wire on the terminals didn't give me any spark at all - after all the spark you get on the wire looks tiny - but using the proper driver completely this solved the problem for me. Hope it does for you. Quote Link to comment Share on other sites More sharing options...
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