Emerald ECU, wasted spark and timing light

[Lesliehedley]

I've been running my 400SE with an Emerald ECU and NGK BPR6EIX plugs tuned by Jules for a few years now using the distributor to deliver the spark.

I recently decide to try wasted spark with coil packs basically to see if it made the idle any smoother and also as an interesting project. Before I started, I checked where the timing was set using my timing light so that I could check after I had the coil packs working just to double check I hadn't changed anything.

I used coil packs and plug leads from the cerbera. I cut the leads to length and put new ends on them. Everything went well and once I had it running I tried to checked the timing. This is where things started to go wrong. I couldn't get the timing light to work on lead 1 so I tried lead 6 which is fired at the same time as lead 1. This gave a good solid light and I was able to check the timing which was correct.

I was puzzled by the fact the timing light wouldn't work on lead 1 and thinking perhaps I had made the lead incorrectly I decided to try the timing light on all cylinders. This is where it gets weird. All the odd cylinders gave no timing light or very sporadic light. All the even cylinders gave a good solid light. I tried swapping leads from one side to the other and also changing leads around on the coil packs in case I had a dodgy coil pack. I got the same result whatever I change. I even went back to the old lead from cylinder 1 used on the distributor, put a new connector on it and tried that. Still the same result.

I came to the conclusion that the only thing I hadn't checked was the plugs, so it must be them. Maybe the gaps weren't big enough on the odd cylinders. So I checked the plugs and gapped them at 29 thou. Most of the even cylinders were ok but some of the odd cylinders were a bit smaller than that. It made no difference. So I swapped the plugs in cylinders 1 and 2 expecting to find the light working on cylinder 1 and not 2. Much to my surprise I found both plugs gave a light. Then I realised I hadn't reconnected plug lead 1. When I reconnected it, I got no light on lead 1 but a good light on lead 2.

So there we are. I still have a timing light that works on the even cylinders but not on the odd cylinders, but I do get a light on the odd cylinders if I disconnect the lead from the plug. I know there are some very clever people on here that really understand the ignition systems etc. I just hope someone can help. Can anyone explain what is going on here? I'm bamboozled. Sorry it's so long but I wanted to explain everything I did in as much detail as possible to help the experts.

[rev-erend]

I have found the inductive type pickup on most timing lights sometimes struggle with the plug lead insulation. Sometimes you just have to fit an old poor quality lead.

Next to confirm all are getting a signal I use spark plug tell tales and even noid lights on the injectors.

The plug colour can also be checked.

Edited by rev-erend on Monday 25th September 13:47

[Lesliehedley]

Update:
The timing light I was using was very old. I have now bought a new timing light and I get a light on all eight cylinders. What is odd is that the rate of the light is twice as fast on the even bank as it is on the odd bank. So it would appear that the even bank is getting the double spark per cylinder ( actual spark and wasted spark) but the odd bank only gets the actual spark and the wasted must be a weak spark which doesn't trigger the light. The engine runs apparently on all eight cylinders but the weak spark on the odd bank makes no sense.