MickyPo

All working as it should. New ECU with the old coil pack. The new coil pack does not work on cyllinder 2 and has a big crack on it on coil no2. I don't know what caused it - either bad copy or my loom has an intermittent fault which I could not find. Of course time will tell but for now it's working.

I didn't do a test drive but as of now it is working well - it starts and runs on all cyllinders without fail where before I could not get the cyl2 to fire at all. I did check the wires as well as I could ie continuity and for short to both positive and negative whilst puling on them in within reason and they all look good. I will test the new coil (not working coil) on the bench tomorrow for confirmation..

Update: Got new ECU and had it cloned of the old one. I've installed it and to my surprise gave the same issue on cyl 2 - no spark. I took the old coil in the house and connected the plus and minus to a spare battery and that allowed me to give an impuls to generate spark. I could get a spark on all of them. I've installed the old coil connected to the new ECU and now it runs on all pistons.. what's surprising to me is that both the old ECU and brand new coil pack have issues on cyllinder 2 !? Once again, many thanks for your support, it's much appreciated !

Thank you for that, I've ordered a used one, hopefully by the end of next week I'll get it working. I'll keep you posted

If it will help anyone in the future I found this to be an easy way of removing the ECU :

Yes that is 3.4v with the cable connected on ECU side but not coil pack side. The connectors look dry and clean, I've opened the ECU also and it is clean, closely inspected solder joints and they all look good with reasonable confidence. I've traced the traces a fair bit back towards the processor and they have continuity as far as I can trace them

Thank you for that! So pin 3 (cyllinder 2 - the bad one ) being at 3.4V whils the other ones showing 0V indicates a ECU problem I guess.. I'll look for a test/repair shop for that, if anyone has any good suggestions it will be much appreciated Once again many thanks and I'll keep you posted on the progress

Please find attached a photo with the vin Also: The coil pack input has 6 wires 1 and 6 are thicker And 2-5 are thinner The thicker ones are positive and negative 12 v. Am I right in assuming that the thinner ones are for signal for each piston ? What I find courious is that pin 2,4and 5 have 0v on them with ignition on but the pin 3 which I assume corresponds to cilinder 2 signal has 3.4 v on it ?

Thank you for that The 5-8 characters are : e41u

If I understand correctly the engine code is the 8th digit on vin !? That would be U

Hi everybody ! I have an issue with cylinder 2 not getting spark I've changed the sparkplugs, leads and the ignition coil pack. For some years now I had intermittent no2 misfire, now it stopped altogether. I've put a spare lead and sparkplug "in the air" and on cyl 4 it gives spark and cyllinder 2 it doesn't. I've checked the wires going from ECU to the coil pack: -the four thinner ones measure (2-3 ohms) with no short to ground or positive. -of the two thick ones: one is 2-3 ohm but one is 30 ohm ... ( Short from battery terminal to coil input) and 30 ohm from battery terminal to ECU output and 30 ohm from coil input to ECU output. Question: 1 Is this supposed to be a straight wire from ECU to ignition coil? 2 Does anyone know where to find the detailed wiring diagram for the ignition system ? 3 anything that I might be able to check that will cause the ECU to not send signal to only one cyllinder other that faulty ECU ? ( I removed and opened the ECU and I haven't seen any signs of corrosion etc) Any help would be greatly appreciated !! Oh forgot to add it's a Octavia MK1 2003 estate