I just bought a 1990 xjs with v12. Many issues but trying to get it running first.
I installed a new battery and it did start but only the passenger side was running. I had already installed a new rotor, the old one wasn't damaged. Cap looked good as well. I'm guessing the next thing is the coil pack mounted right above the distributor?? Which side is A and which is B. Thanks

 

Might also be one of the control modules above the radiator. Not sure how to test them.

But if you have a DVOM you can test the coils.

"A" bank is the RH side, as viewed from sitting in the car looking forward

Cheers
DD

 

thanks I'll check those two things out. Also when I put the battery in today and had the key on I only had power to the dash no window or top ???

 

To diagnose to coil or ignitor.

Swap input to both coils and the HT leads at the distributor, if the problem stays on the same bank the coil and HT leads are good.

Put everything back to original.

If the problem moves to the other bank swap the HT leads at the distributor and coil. If the problem moves then the HT lead is bad.

Put everything back to original.

If the problem does not move its either the ignitor or wiring. Swap the plugs on the ignitors these are on the radiator top support.

If the problem stays on the same bank then the wiring is the problem. If the problem moves then you have a bad ignitor.

Put everything back to original.

 

I read this quote like a murder mystery! Professor Plum in the Dizzy with a HT lead!!!

Excellent diagnosis process!