First I would like to thank members of this forum for their knowledge. It has helped me on many issues including A-drum repair. Today's problem. my '98 xj8 is not charging the battery. With the car running I,m getting 11.3 volts at the battery. I also checked the ground to the body and the protection module and get 11.3 volts at all terminals. At the generator i,m getting 14.4 volts. At the starter i,m getting 14.4 volts at the terminal and at the cable going to the battery at the starter connection. Is there anything between the starter and the protection module that would give me different voltages. When the battery has a full charge the car will start so I believe the cable would have to be good. Any ideas would be appreciated.

 

So, you have a 3.1 volt voltage loss. It should be easy enough to find. But before i got out the meter, I would have a look at the "false bulkhead" connections mounted on the boxes near the firewall where a cable connects on each side. And you mentioned the ground to the body. There are two ground straps, one from body to chassis and one from engine to chassis. Look for corrosion and tightness.

To test with a meter, you will look for voltage loss. If any of the path's voltage is greater than about .4 volts, you found it! First read the case of the alternator to the chassis. Then the chassis to the battery - terminal. Then the battery + to the output of the protection module. Then the protection module to the false bulkheads. Then false bulkhead to the alternator positive terminal. If you have not found it by then, you have disproved Kirchoff's voltage law!

 

Thank You sparkenzap. It was the false bulkhead. The connection was loose. The plastic was partially melted. I took the bulkhead off another jag I have. I'm getting a full charge at the battery. Problem solved. Thanks again.