Having problems with your 1994 Jaguar XJ6 ?
No spark, only 7.5v on coil +ve.Starts with ext.12v supply.
Measure battery voltage when cranking, if below about 10v then could be the problem. Not enough information for a full diagnosis, so presume the ext 12v supply was on the coil? Try this diagnosis procedure: Put voltmeter on battery + and on to coil + and measure volt drop when cranking. It should be small. Keep voltmeter on coil and keep probing all the way back through any points you can get to the coil wire until you get to the ignition relay, keep checking volt drop until you get to the ignition switch. You should be looking at a fraction of a volt all the way until there. If more, you have a dodgy connection or relay. Sometimes, easiest way is to rewire from where you know there is a low volt drop as finding a broken cable in a wiring loom is nigh impossible. I've had to do this a couple of times before on my classic cars.
Repair Help & Product Troubleshooting for 1994 Jaguar XJ6
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