Ignition coil sparking

XJ40
21

I think you misunderstand

Th point at witch the ECU decides to generate the spark is transferred to the plug lead from the rotor and depending where that rotor is in relation to the pick-up, if the gap is too large the spark will not always jump that gap so rotating the distributor slightly may reduce the gap and allow the spark to get to the plug

1 Like
22

I rotated the dizzy a few degrees counterclockwise and started the car. It warmed up for maybe 15 minutes and all was good. I took her for a drive (maybe 10 minutes) and still good. Left it running and checked it in the driveway - still good. Took it for another drive (maybe 15 minutes) and no issues. Back in the driveway now running smoothly. Itā€™s been up to around 50mph at this point and gone farther than it has since the repair without issueā€¦

Iā€™m going to take it out again shortly and push it a little to see what she does. Keeping my fingers crossedā€¦

23

Just got back from another road trip. Drove it like I stole it and it didnā€™t miss at all. I wonā€™t have a chance to get it on the highway until tomorrow but I think it may be all set.

Many thanks Bryan and to everyone else who responded!

1 Like
24

William ā€¦

One thing I learned a long time ago is to NEVER argue with success :grinning:

But unless you changed the position of the distributor I still donā€™t understand how that could have been the cause. So fingers crossed and happy motoring.

25

Groove - look back a couple of posts - the dizzy was moved:

26

Mike ā€¦

I said in my post ā€¦ ā€œunless you changed the position of the distributor I still donā€™t understand how that could have been the CAUSE.ā€

I believe William said he moved the distributor AFTER the problem occurred as a means of troubleshooting.

So Iā€™m still scratching my head figuring out how the car ran fine with the distributor in the position it originally was and once the problem occurred moving the distributor cured it. Those distributors (especially when theyā€™ve never been touched) donā€™t vibrate and move around by themselves. Additionally, the fact that the car would run fine for a time and then act up doesnā€™t sound like a misaligned distributor but more like a coil or plug wire problem.

1 Like
27

Maybe the plug on the coil was tighter and therefore gave better insulation on the old coil.