Testing/Checking XJ550 Pickup coils

My Son ran my old XJ550 at the Male and cleaned it all up and put road tyres back on afterwards.

On the 2nd or 3rd ride afterwards it started struggling to rev (cutting with excess throttle) and then cut out. At this point the starter motor also decided to lunch itself.

He's had the starter motor rebuilt and it now cranks really well, however we have no spark.

He has swapped out the TCI unit, we have checked the resistance across both sides of the ignition coils and to the end of the spark plug wires which all check out.

However, when I try and test the resistance across the pickup coils at the plug that goes into the TCI unit I get no continuity between the Black/grey and Black/Orange wires where I believe I should be seeing 650ohms +/- 20%

Any ideas why this would be, please, as I believe it would be odd for both to go at the same time?

Any other tests I should try to get to the bottom of this?

Thanks!

 

Have you checked the black earth wire for insulation damage under the frame?

 

No, that's a good shout, will check tomorrow

 

@Franz you were correct! Unsheathed the part where the 2 earths are joined and tested that and showed 535ohms, which is well inside the 525 +/- 10%, so bypassed the wire from there to the TCI and hey presto!

Thanks!