This is on a 2001 5JJ R1 engine.

I thought I'd sorted the issue of 2 cylinder running with new plugs and a coil (to replace the one that melted itself against the exhaust manifold), seems not!

The coils are fine, the feed to them is not. There are 4 wires to two coils:

- One red/black ignition wire spliced into two
- One grey wire (signal wire?) for cylinders 2 & 3
- One orange wire for cylinders 1 & 4

Weirdly the coil that had a slightly melted casing was the one controlling the two cylinders that currently work. Its the feed to the other coil which seems bad. Could it be a massive coincidence that just after the coil fell onto the exhaust that the problem with ignition happened immediately after?

Anyway, it seems I'm not getting a signal down the orange wire. This wire starts from the ignition control unit/ECU with the grey one, then to a connector just upstream of the coils.

I'll try a continuity test tomorrow, but it means stripping down some of the engine bay. I'm hoping I don't need to swap the ignition control unit for a new one.

In the meantime, has anyone had a similar problems, or any suggestions? I am annoyed having missed all this lovely weather!

James

An alternate theory, the CDI Unit or trigger unit went bad, which caused rough lumpy running, which caused the coil bracket to fracture....

Unless its a broken wire or a bad connection, I think you're into replacement trigger or CDI unit..

Sorted now. I replaced the ICU and I'm back to 4 cylinders. Initially I used the new (eBay) coils but turns out one spark plug cap was broken internally and then gaffer taped up. The one I melted worked!